Ieee Guide For Onsite Acceptance Tests Of Electrical Equipment A

IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

IEEE-SA Board of Governors and IEEE Power and Energy Society Sponsored by the Corporate Advisory Group IEEE Substations Committee IEEE Switchgear Committee IEEE Transformers Committee

IEEE 3 Park Avenue New York, NY 10016-5997 USA

IEEE Std 1861™-2014

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861™-2014

IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above Sponsor

Corporate Advisory Group of the

IEEE Board of Governors and IEEE Substations Committee IEEE Switchgear Committee IEEE Transformers Committee of the IEEE Power and Energy Society Approved 12 June 2014

IEEE-SA Standards Board

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

Abstract: On-site acceptance tests of ultra-high-voltage power equipment are subject to this guide. Criteria and requirements for test items, conditions, methods, and results are established. The stated specifications and requirements, both technical and for testing, are universally needed for acceptance tests on-site and commissioning of ultra-high-voltage power equipment, including power transformers, reactors, capacitive voltage transformers, bushing-type current transformers, gas-insulated switchgear, air insulated grounding switches, air insulated disconnecting switches, bushings, metal-oxide surge arresters, suspension insulators, post insulators, and insulating oil, etc. It will be sufficient for most installations. Keywords: air-insulated disconnecting switch, air-insulated grounding switch, bushing, bushingtype current transformer, capacitive voltage transformer, factory test, gas-insulated switchgear, IEEE 1861™, insulating oil, system commissioning, metal-oxide surge arrester, on-site acceptance test, post insulator, power transformer, reactor, suspension insulator, ultra-high voltage. •

The Institute of Electrical and Electronics Engineers, Inc. 3 Park Avenue, New York, NY 10016-5997, USA Copyright © 2014 by The Institute of Electrical and Electronics Engineers, Inc. All rights reserved. Published 1 August 2014. Printed in the United States of America. IEEE is a registered trademark in the U.S. Patent & Trademark Office, owned by The Institute of Electrical and Electronics Engineers, Incorporated. PDF: Print:

ISBN 978-0-7381-9196-6 ISBN 978-0-7381-9197-3

STD98707 STDPD98707

IEEE prohibits discrimination, harassment, and bullying. For more information, visit http://www.ieee.org/web/aboutus/whatis/policies/p9-26.html. No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without the prior written permission of the publisher.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

Important Notices and Disclaimers Concerning IEEE Standards Documents IEEE documents are made available for use subject to important notices and legal disclaimers. These notices and disclaimers, or a reference to this page, appear in all standards and may be found under the heading “Important Notice” or “Important Notices and Disclaimers Concerning IEEE Standards Documents.”

Notice and Disclaimer of Liability Concerning the Use of IEEE Standards Documents IEEE Standards documents (standards, recommended practices, and guides), both full-use and trial-use, are developed within IEEE Societies and the Standards Coordinating Committees of the IEEE Standards Association (“IEEE-SA”) Standards Board. IEEE (“the Institute”) develops its standards through a consensus development process, approved by the American National Standards Institute (“ANSI”), which brings together volunteers representing varied viewpoints and interests to achieve the final product. Volunteers are not necessarily members of the Institute and participate without compensation from IEEE. While IEEE administers the process and establishes rules to promote fairness in the consensus development process, IEEE does not independently evaluate, test, or verify the accuracy of any of the information or the soundness of any judgments contained in its standards. IEEE does not warrant or represent the accuracy or content of the material contained in its standards, and expressly disclaims all warranties (express, implied and statutory) not included in this or any other document relating to the standard, including, but not limited to, the warranties of: merchantability; fitness for a particular purpose; non-infringement; and quality, accuracy, effectiveness, currency, or completeness of material. In addition, IEEE disclaims any and all conditions relating to: results; and workmanlike effort. IEEE standards documents are supplied “AS IS” and “WITH ALL FAULTS.” Use of an IEEE standard is wholly voluntary. The existence of an IEEE standard does not imply that there are no other ways to produce, test, measure, purchase, market, or provide other goods and services related to the scope of the IEEE standard. Furthermore, the viewpoint expressed at the time a standard is approved and issued is subject to change brought about through developments in the state of the art and comments received from users of the standard. In publishing and making its standards available, IEEE is not suggesting or rendering professional or other services for, or on behalf of, any person or entity nor is IEEE undertaking to perform any duty owed by any other person or entity to another. Any person utilizing any IEEE Standards document, should rely upon his or her own independent judgment in the exercise of reasonable care in any given circumstances or, as appropriate, seek the advice of a competent professional in determining the appropriateness of a given IEEE standard. IN NO EVENT SHALL IEEE BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO: PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE PUBLICATION, USE OF, OR RELIANCE UPON ANY STANDARD, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE AND REGARDLESS OF WHETHER SUCH DAMAGE WAS FORESEEABLE.

Translations The IEEE consensus development process involves the review of documents in English only. In the event that an IEEE standard is translated, only the English version published by IEEE should be considered the approved IEEE standard.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

Official statements A statement, written or oral, that is not processed in accordance with the IEEE-SA Standards Board Operations Manual shall not be considered or inferred to be the official position of IEEE or any of its committees and shall not be considered to be, or be relied upon as, a formal position of IEEE. At lectures, symposia, seminars, or educational courses, an individual presenting information on IEEE standards shall make it clear that his or her views should be considered the personal views of that individual rather than the formal position of IEEE.

Comments on standards Comments for revision of IEEE Standards documents are welcome from any interested party, regardless of membership affiliation with IEEE. However, IEEE does not provide consulting information or advice pertaining to IEEE Standards documents. Suggestions for changes in documents should be in the form of a proposed change of text, together with appropriate supporting comments. Since IEEE standards represent a consensus of concerned interests, it is important that any responses to comments and questions also receive the concurrence of a balance of interests. For this reason, IEEE and the members of its societies and Standards Coordinating Committees are not able to provide an instant response to comments or questions except in those cases where the matter has previously been addressed. For the same reason, IEEE does not respond to interpretation requests. Any person who would like to participate in revisions to an IEEE standard is welcome to join the relevant IEEE working group. Comments on standards should be submitted to the following address: Secretary, IEEE-SA Standards Board 445 Hoes Lane Piscataway, NJ 08854 USA

Laws and regulations Users of IEEE Standards documents should consult all applicable laws and regulations. Compliance with the provisions of any IEEE Standards document does not imply compliance to any applicable regulatory requirements. Implementers of the standard are responsible for observing or referring to the applicable regulatory requirements. IEEE does not, by the publication of its standards, intend to urge action that is not in compliance with applicable laws, and these documents may not be construed as doing so.

Copyrights IEEE draft and approved standards are copyrighted by IEEE under U.S. and international copyright laws. They are made available by IEEE and are adopted for a wide variety of both public and private uses. These include both use, by reference, in laws and regulations, and use in private self-regulation, standardization, and the promotion of engineering practices and methods. By making these documents available for use and adoption by public authorities and private users, IEEE does not waive any rights in copyright to the documents.

Photocopies Subject to payment of the appropriate fee, IEEE will grant users a limited, non-exclusive license to photocopy portions of any individual standard for company or organizational internal use or individual, non-commercial use only. To arrange for payment of licensing fees, please contact Copyright Clearance Center, Customer Service, 222 Rosewood Drive, Danvers, MA 01923 USA; +1 978 750 8400. Permission to photocopy portions of any individual standard for educational classroom use can also be obtained through the Copyright Clearance Center.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

Updating of IEEE Standards documents Users of IEEE Standards documents should be aware that these documents may be superseded at any time by the issuance of new editions or may be amended from time to time through the issuance of amendments, corrigenda, or errata. An official IEEE document at any point in time consists of the current edition of the document together with any amendments, corrigenda, or errata then in effect. Every IEEE standard is subjected to review at least every ten years. When a document is more than ten years old and has not undergone a revision process, it is reasonable to conclude that its contents, although still of some value, do not wholly reflect the present state of the art. Users are cautioned to check to determine that they have the latest edition of any IEEE standard. In order to determine whether a given document is the current edition and whether it has been amended through the issuance of amendments, corrigenda, or errata, visit the IEEE-SA Website at http://ieeexplore.ieee.org/xpl/standards.jsp or contact IEEE at the address listed previously. For more information about the IEEE SA or IEEE’s standards development process, visit the IEEE-SA Website at http://standards.ieee.org.

Errata Errata, if any, for all IEEE standards can be accessed on the IEEE-SA Website at the following URL: http://standards.ieee.org/findstds/errata/index.html. Users are encouraged to check this URL for errata periodically.

Patents Attention is called to the possibility that implementation of this standard may require use of subject matter covered by patent rights. By publication of this standard, no position is taken by the IEEE with respect to the existence or validity of any patent rights in connection therewith. If a patent holder or patent applicant has filed a statement of assurance via an Accepted Letter of Assurance, then the statement is listed on the IEEE-SA Website at http://standards.ieee.org/about/sasb/patcom/patents.html. Letters of Assurance may indicate whether the Submitter is willing or unwilling to grant licenses under patent rights without compensation or under reasonable rates, with reasonable terms and conditions that are demonstrably free of any unfair discrimination to applicants desiring to obtain such licenses. Essential Patent Claims may exist for which a Letter of Assurance has not been received. The IEEE is not responsible for identifying Essential Patent Claims for which a license may be required, for conducting inquiries into the legal validity or scope of Patents Claims, or determining whether any licensing terms or conditions provided in connection with submission of a Letter of Assurance, if any, or in any licensing agreements are reasonable or non-discriminatory. Users of this standard are expressly advised that determination of the validity of any patent rights, and the risk of infringement of such rights, is entirely their own responsibility. Further information may be obtained from the IEEE Standards Association.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

Participants At the time this IEEE guide was completed, the P1861 sub-working group of Ultra-High-Voltage AC Standards Working Group had the following membership:

Bo Li, Chair Hui Chao, Co-Chair Jiangbo Chen, Secretary Ying Li, Secretary Raj Ahuja Liangeng Ban Weijiang Chen Denis Dufournet Ken Edwards Jianbin Fan Francois Gallon Jian Guo Hiroyuki Hama Jing Han

Fengjun He Yan He Hiroki Ito Hermann Koch Guangfan Li Liuling Li Makoto Miyashita Masatomo Ono Yukiyasu Shirasaka

Kyoichi Uehara Xiaogang Wang Xiaoning Wang Yang Xiao Yonghua Yin Yu Yin Bin Zheng Jian Zhang Cuixia Zhang Shuqi Zhang

The Working Group gratefully acknowledges the contributions of the following entities and participants. Without their assistance and dedication, this standard would not have been completed. The following entities submitted technical contributions or commented of the draft standard at various stages of the project development. Alstom Grid Bonneville Power Administration Hitachi, Ltd.

InterNational Electrical Testing Association (NETA) Japan AE Power Systems Corporation Mitsubishi Electric Corporation Quanta Technology LLC

Siemens Corporation State Grid Corporation of China (SGCC) Toshiba Corporation Waukesha Electric Systems, Inc.

The following members of the entity balloting committee voted on this guide. Balloters may have voted for approval, disapproval, or abstention. Alstom Beijing Jiaotong University Beijing Sifang Automation Co., Ltd BII Group Holdings Ltd. China Datang Corporation

Hitachi, Ltd. InterNational Electrical Testing Association (NETA) Marvell Semiconductor, Inc. Mitsubishi Electric Corporation Quanta Technology LLC

Siemens Corporation Southwest Jiaotong University State Grid Corporation of China (SGCC) Toshiba Corporation Waukesha Electric Systems, Inc.

vi

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

When the IEEE-SA Standards Board approved this guide on 12 June 2014, it had the following membership: John Kulick, Chair Jon Walter Rosdahl, Vice Chair Richard H. Hulett, Past Chair Konstantinos Karachalios, Secretary Peter Balma Farooq Bari Ted Burse Clint Chaplin Stephen Dukes Jean-Philippe Faure Gary Hoffman

Michael Janezic Jeffrey Katz Joseph L. Koepfinger* David J. Law Hung Ling Oleg Logvinov Ted Olsen Glenn Parsons

Ron Petersen Adrian Stephens Peter Sutherland Yatin Trivedi Phil Winston Don Wright Yu Yuan

*Member Emeritus

Also included are the following nonvoting IEEE-SA Standards Board liaisons: Richard DeBlasio, DOE Representative Michael Janezic, NIST Representative

Patrick Gibbons IEEE-SA Content Publishing Soo Kim IEEE-SA Standards Technical Community

vii

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

Introduction This introduction is not part of IEEE Std 1861™-2014, IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above.

With the increase in voltage levels, the reliability and safety of high-voltage electric equipment is facing new challenges. There is a need to have consensus on a series of technical criteria and requirements for onsite acceptance tests for ultra-high-voltage (UHV) electric equipment to detect the damages or abnormal conditions that may occur during the transportation and installation processes and to determine whether equipment can be put into operation reliably and safely for power systems. AC transmission systems of 1000 kV or greater have been established and operated with full-voltage in China and are also currently in various stages of development in other countries. However, there is a lack of suitable UHV transmission system commissioning procedures and technical information. Therefore, it is necessary to formulate a series of consensus technical requirements and criteria so as to facilitate the development of UHV systems and help ensure their successful commissioning. This guide proposes on-site acceptance tests, relevant test items, test methods, and evaluation criteria for power transformers, reactors, capacitive voltage transformers (CVTs), bushing-type current transformers (CTs), gas-insulated switchgear, air-insulated grounding switches, air-insulated disconnecting switches, bushings, metal-oxide surge arresters (MOSAs), suspension insulators, post insulators, and insulating oil. System commissioning consists of two parts. The first part is the preparation work before commissioning, including simulation and making commissioning schemes, testing schemes, and implementation schedules. The second part is the commissioning of projects with detailed explanation of conditions and contents.

viii

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

Contents 1. Overview .................................................................................................................................................... 1 1.1 Scope ................................................................................................................................................... 1 1.2 Purpose ................................................................................................................................................ 1 2. Normative references.................................................................................................................................. 2 3. Definitions, acronyms, and abbreviations .................................................................................................. 3 3.1 Definitions ........................................................................................................................................... 3 3.2 Acronyms and abbreviations ............................................................................................................... 3 4. On-site acceptance tests .............................................................................................................................. 4 4.1 General ................................................................................................................................................ 4 4.2 Power transformers .............................................................................................................................. 4 4.3 Reactors ............................................................................................................................................... 7 4.4 Capacitive voltage transformers (CVTs) ............................................................................................. 9 4.5 Bushing-type CTs ...............................................................................................................................12 4.6 Gas-insulated switchgear ....................................................................................................................13 4.7 Air-insulated grounding switches .......................................................................................................15 4.8 Air-insulated disconnecting switches .................................................................................................16 4.9 Bushings .............................................................................................................................................17 4.10 MOSAs .............................................................................................................................................18 4.11 Suspension insulators and post insulators .........................................................................................19 4.12 Insulating oil .....................................................................................................................................19 5. System commissioning ..............................................................................................................................20 5.1 General ...............................................................................................................................................20 5.2 System commissioning items .............................................................................................................20 Annex A (informative) On-site acceptance tests for UHV transformers—Practical examples based on the experiences in China......................................................................................................................................33 A.1 Applied voltage test ...........................................................................................................................35 A.2 Induced voltage test with partial discharge measurement (IVPD) .....................................................36 Annex B (informative) On-site tests for gas-insulated switchgear—Practical examples based on the experiences in China......................................................................................................................................39 B.1 Tests for gas-insulated switchgear .....................................................................................................39 B.2 Dielectric test on the main circuit ......................................................................................................39 Annex C (informative) Simulation study for system commissioning............................................................42 C.1 Background ........................................................................................................................................42 C.2 Electromagnetic transient analysis for system commissioning ..........................................................42 C.3 Power flow and stability analysis contents for commissioning system..............................................44 Annex D (informative) Typical measurement items of system commissioning ............................................47 D.1 Artificial single phase-to-ground fault test ........................................................................................47 D.2 Switching on/off test of on-load UHV transformers ..........................................................................52 D.3 Switching on/off test of tertiary connected capacitors .......................................................................53 D.4 Audible-noise measurement of substation and transmission lines .....................................................54 Annex E (informative) Bibliography .............................................................................................................55

ix

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above IMPORTANT NOTICE: IEEE Standards documents are not intended to ensure safety, security, health, or environmental protection, or ensure against interference with or from other devices or networks. Implementers of IEEE Standards documents are responsible for determining and complying with all appropriate safety, security, environmental, health, and interference protection practices and all applicable laws and regulations. This IEEE document is made available for use subject to important notices and legal disclaimers. These notices and disclaimers appear in all publications containing this document and may be found under the heading “Important Notice” or “Important Notices and Disclaimers Concerning IEEE Documents.” They can also be obtained on request from IEEE or viewed at http://standards.ieee.org/IPR/disclaimers.html.

1. Overview 1.1 Scope This guide applies to on-site acceptance tests of electrical equipment and system commissioning of 1000-kV ac and above. It identifies criteria and recommendations for test items, conditions, methods, and results. The stated recommendations, both technical and for testing, are universally needed for on-site acceptance tests and commissioning of 1000 kV ac and above ultra-high-voltage (UHV) power equipment, including power transformers, reactors, capacitive voltage transformers (CVTs), bushing-type current transformers (CTs), gas-insulated switchgear, air insulated grounding switches, air insulated disconnecting switches, bushings, metal-oxide surge arresters (MOSAs), suspension insulators, post insulators, and insulating oil.

1.2 Purpose The intent of this guide is to identify on-site acceptance tests of 1000-kV ac and above electrical equipment. This guide also promotes the application and development of on-site acceptance test methodology.

1

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

This guide also provides uniform technology specification recommendations for commissioning of 1000-kV ac and above transmission systems. It also provides the recommendations of testing, acceptance criteria, and safety specifications. This guide also provides sufficient technical support for widespread and long-distance UHV ac transmission and promotes system operating safety and reliability.

2. Normative references The following referenced documents are indispensable for the application of this document (i.e., they must be understood and used, so each referenced document is cited in text and its relationship to this document is explained). For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments or corrigenda) applies. IEC 60044-5:2004, Instrument transformers—Part 5: Capacitor voltage transformers. 1 IEC 60076-1: 2011, Power transformers—Part 1: General. IEC 60076-3:2000, Power transformers—Part 3: Insulation levels, dielectric tests and external clearances in air. IEC 60076-18:2012, Power transformers—Part 18: Measurement of frequency response. IEC 60137:2009, Insulated bushings for alternating voltages above 1000 V. IEC 60383-1:1993, Insulators for overhead lines with a nominal voltage above 1000 V—Part 1: Ceramic or glass insulator units for a.c. systems—Definitions, test methods and acceptance criteria. IEC 60599:2007, Mineral oil-impregnated electrical equipment in service—Guide to the interpretation of dissolved and free gases analysis. IEC 60694:2002, Common specifications for high-voltage switchgear and controlgear standards. IEC 62271-1:2011, High-voltage switchgear and controlgear—Part 1: Common specifications. IEC 62271-102:2001, High-voltage switchgear and controlgear—Part 102: Alternating current disconnectors and earthing switches. IEC 62271-203:2003, High-voltage switchgear and controlgear—Part 203: Gas-insulated metal-enclosed switchgear for rated voltages above 52 kV. IEEE Std C37.100.1™-2007, IEEE Standard of Common Requirements for High Voltage Power Switchgear Rated Above 1000 V. 2,3 IEEE Std C37.122™-2010, Standard for High Voltage Gas-Insulated Substations Rated Above 52 kV.

1

IEC publications are available from the Sales Department of the International Electrotechnical Commission, 3 rue de Varembé, PO Box 131, CH-1211, Geneva 20, Switzerland (http://www.iec.ch/). IEC publications are also available in the United States from the Sales Department, American National Standards Institute, 25 West 43rd Street, 4th Floor, New York, NY 10036, USA (http://www.ansi.org). 2 The IEEE standards or products referred to in this clause are trademarks of The Institute of Electrical and Electronics Engineers, Inc. 3 IEEE publications are available from The Institute of Electrical and Electronics Engineers, 445 Hoes Lane, Piscataway, NJ 08854, USA (http://standards.ieee.org/).

2

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

IEEE Std C57.12.00™-2010, IEEE Standard for General Requirements for Liquid-Immersed Distribution, Power, and Regulating Transformers. IEEE Std C57.12.90™-2010, IEEE Standard Test Code for Liquid-Immersed Distribution Power and Regulating Transformers. IEEE Std C57.13™-2008, IEEE Standard Requirements for Instrument Transformers. IEEE Std C57.13.1™-2006, IEEE Guide for Field Testing of Relaying Current Transformers. IEEE Std C57.13.5™-2009, IEEE Standard of Performance and Test Requirements for Instrument Transformers of a Nominal System voltage of 115 kV and Above. IEEE Std C57.19.00™-2004, IEEE Standard General Requirements and Test Procedure for Power Apparatus Bushings. IEEE Std C57.93™-2007, IEEE Guide for Installation and Maintenance of Liquid-Immersed Power Transformers. IEEE Std C62.11™-2005, IEEE Standard for Metal-Oxide Surge Arresters for AC Power Circuits (> 1 kV).

3. Definitions, acronyms, and abbreviations 3.1 Definitions For the purposes of this document, the following terms and definitions apply. The IEEE Standards Dictionary Online should be consulted for terms not defined in this clause. 4 on-site acceptance tests: Inspections and tests are performed (or checked) on the correct operation and dielectric integrity of the equipment after shipping and site assembly, verifying the results of the factory tests. The on-site acceptance test does not include power grid tests. system commissioning: A series of tests carried out after an on-site acceptance test to confirm the integrity of the equipment and system in a power grid before putting it into service. NOTE—Some countries have regulations such as the Electricity Business Act, Technical Regulations on Electrical Equipment, Standard on Power Plants and Substations (Non-governmental), and Standards on Electrical Equipment (Non-governmental). 5

3.2 Acronyms and abbreviations ac

alternating current

CT

current transformer

CVT

capacitive voltage transformer

4 IEEE Standards Dictionary Online subscription is available at: http://www.ieee.org/portal/innovate/products/standard/standards_dictionary.html. 5 Notes in text, tables, and figures of a standard are given for information only and do not contain requirements needed to implement this standard.

3

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

dc

direct current

DGA

dissolved gas analysis

FRA

frequency-response analysis

IVPD

induced voltage test with partial discharge measurement

MOSA

metal-oxide surge arrester

UHV

ultra-high voltage

VT

voltage transformer

4. On-site acceptance tests 4.1 General On-site acceptance tests for newly installed electrical equipment are an important approach to judge whether equipment is normal or abnormal after transportation and installation. On-site acceptance test results must be analyzed and compared carefully with those from the factory test. The influence of different test conditions, such as humidity and the ambient temperature, should be taken into consideration when making comparisons.

4.2 Power transformers 4.2.1 On-site acceptance tests for UHV transformers For the procedure followed for field tests, the test method should refer to the same kind of tests described in relevant publications for factory tests, such as IEEE Std C57.12.00-2010, IEEE Std C57.12.90-2010, IEEE Std C57.93-2007, IEC 60599:2007, and the IEC 60076 series. The test methods and their descriptions listed below are applicable for UHV transformers. 6 UHV transformers should be subjected to on-site acceptance tests as specified below. The details/ procedures of on-site tests for a UHV transformer based on experiences in China are given in Annex A. Common tests include the following:

6



Leak testing with pressure (tightness test)



Winding resistance measurement



Ratio tests



Polarity check

Information on references can be found in Clause 2.

4

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above



Insulation resistance test on each winding to ground and between windings including bushings



Dissipation factor (tanδ) and capacitance measurement on each winding to ground and between windings



Core and frame insulation check



Tests on bushings



Insulating oil tests



Dissolved gas analysis (DGA) test



Excitation current measurements at reduced voltage



Frequency response analysis (FRA)



Short-circuit impedance measurement at reduced current

Optional tests based on the requirements of the user include the following: 

Applied voltage tests



Induced voltage test with partial discharge measurement (IVPD)

4.2.2 Leak testing with pressure (tightness test) Refer to 11.8 of IEC 60076-1:2011 for leak testing with pressure (tightness test). 4.2.3 Winding resistance measurement Winding resistance measurement tests should include the following: a)

Measurement should be performed for all windings at all tap positions (if any).

b)

Measured values should be compared with the factory test results.

c)

Measured values should be compared with the average value of three phase windings.

4.2.4 Ratio tests Ratio tests should include the following: a)

The voltage ratio should be measured on each tap.

b)

Voltage ratio should correspond to the value on nameplate and the factory test result.

5

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

4.2.5 Polarity check The polarity of single-phase transformers should be checked. The polarity must be the same as that identified on the nameplate. 4.2.6 Insulation resistance test between each winding to ground and between windings including bushings Refer to 10.11 of IEEE Std C57.12.90-2010 for insulation resistance tests between each winding to ground and between windings including bushings. 4.2.7 Dissipation factor (tanδ) and capacitance measurement on each winding to ground and between windings Dissipation factor (tanδ) and capacitance measurement on each winding to ground and between windings should include the following: a)

Terminals to be tested should be connected to the test instrument and the terminals not being tested short-circuited and connected to ground.

b)

Tanδ should be compared with the factory test result considering the temperature difference, and the capacitance value should have no obvious difference with factory test result with certain deviation based on the experience of users.

4.2.8 Core and frame insulation check Refer to 11.2.3 of IEC 60076-1:2011 for the core and frame insulation check. 4.2.9 Tests on bushings Refer to 4.9 of this guide for tests on bushings. 4.2.10 Insulating oil tests Refer to 4.12 of this guide for insulating oil tests. 4.2.11 DGA test The DGA test should be carried out after the completion of oil treatment. If a dielectric test is required, the DGA test should be carried out after the dielectric test. 4.2.12 Excitation current measurements at reduced voltage Excitation current measurements at reduced voltage should include the following: a)

The excitation current should be measured at the same reduced test voltage as the factory test. The test should be carried out before the winding resistance measurement to avoid the influence of residual flux in the core. 6

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

b)

The value of excitation current at reduced test voltage should be compared with the factory test results.

4.2.13 Frequency-response analysis (FRA) Refer to IEC 60076-18:2012 for frequency-response analysis (FRA). 4.2.14 Short-circuit impedance measurement at reduced current Short-circuit impedance measurement at reduced current should include the following: a)

The short-circuit impedance should be measured at the same reduced current as in the factory test.

b)

The value of short-circuit impedance at reduced current should be compared with the factory test results.

4.2.15 Applied voltage tests (optional test) Refer to Annex A for an example of the test method. 4.2.16 Induced voltage test with partial discharge measurement (IVPD) (optional test) Refer to Annex A for an example of the test method.

4.3 Reactors 4.3.1 On-site acceptance tests for reactors For the procedure followed for field tests, the test method should refer to the same kind of tests described in relevant publications for factory tests, such as IEEE Std C57.12.00-2010, IEEE Std C57.12.90-2010, IEEE Std C57.93-2007, IEC 60599:2007, and the IEC 60076 series. The test methods and their descriptions listed below are applicable for UHV reactors. Shunt reactors and neutral-earthing reactors (if any) should be subjected to on-site acceptance tests as specified below. Common tests include the following: a)

Leak testing with pressure (tightness test)

b)

Winding resistance measurement

c)

Insulation resistance tests including bushings

d)

Dissipation factor (tanδ) and capacitance measurement on each winding to ground and between windings

e)

Core and frame insulation check

f)

Tests on bushings 7

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

g)

Insulation oil tests

h)

DGA test

Applied voltage tests are optional based on the user requirements. 4.3.2 Leak testing with pressure (tightness test) Refer to 11.8 of IEC 60076-1:2011 for leak testing with pressure (tightness test). 4.3.3 Winding resistance measurement Refer to 4.2.3 b) and c) of this guide for winding resistance measurement. 4.3.4 Insulation resistance tests including bushings Refer to 10.11 of IEEE Std C57.12.90-2010 for insulation resistance tests including bushings. 4.3.5 Dissipation factor (tanδ) and capacitances measurement on each winding to ground and between windings Refer to 4.2.7 of this guide for dissipation factor (tanδ) and capacitances measurement on each winding to ground and between windings. 4.3.6 Core and frame insulation check Refer to 11.2.3 of IEC 60076-1:2011 for the core and frame insulation check. 4.3.7 Tests on bushings Refer to 4.9 of this guide for tests on bushings. 4.3.8 Insulating oil tests Refer to 4.12 of this guide for insulating oil tests. 4.3.9 DGA test The DGA test should be carried out after the completion of oil treatment. If a dielectric test is required, the DGA test should be carried out after the dielectric test. 4.3.10 Applied voltage tests (optional test) Refer to Annex A for an example of the test method.

8

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

4.4 Capacitive voltage transformers (CVTs) 4.4.1 On-site acceptance tests for CVTs For the procedure followed for field tests, the test method should refer to same kind of tests described in relevant publications, such as IEEE Std C57.13.5-2009, IEEE Std C57.13-2008, and IEC 60044-5:2004. The test methods and their descriptions listed below are applicable for UHV CVTs. Common tests include the following: a)

Insulation resistance measurement of capacitor voltage dividers’ low-voltage terminal to earth terminal

b)

Capacitance and dissipation factor (tanδ) measurement of capacitor voltage dividers

c)

Tightness of the liquid-filled capacitor voltage dividers

d)

Winding resistance measurement of electromagnetic units

e)

Insulation resistance measurement of each component of electromagnetic units

f)

Connection check between components of electromagnetic units

g)

Tightness of electromagnetic units

h)

Accuracy checks (determination of error)

i)

Damper check

A low-frequency withstand test on capacitor voltage dividers is optional based on user requirements. 4.4.2 Insulation resistance measurement of capacitor voltage dividers’ low-voltage terminal to earth terminal Insulation resistance measurement of capacitor voltage dividers’ low-voltage terminal to earth terminal should include the following: a)

The insulation resistance should be tested at 2500 V.

b)

The tested value of insulation resistance should be greater than 1000 MΩ.

4.4.3 Capacitance and dissipation factor (tanδ) measurement of capacitor voltage dividers Capacitance and dissipation factor (tanδ) measurement of capacitor voltage dividers should include the following: a)

Measurement of capacitance and tanδ of each capacitor voltage divider unit should be performed at 10 kV. Measurement of capacitance and tanδ of the intermediate voltage capacitor should be performed at rated voltage. The value of tanδ should not be greater than 0.2%.

b)

The deviation of the capacitance of each capacitor unit and intermediate voltage capacitor unit should be between −5% ~ +10% of rated value. 9

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

c)

If the value of tanδ measured at 10 kV doesn’t meet the requirement, it should be measured at rated voltage instead. When the value of tanδ measured at rated voltage meets the requirement, the capacitor voltage dividers can be considered to be acceptable.

4.4.4 Tightness of the liquid-filled capacitor voltage dividers Tightness of the liquid-filled capacitor voltage dividers should meet the following requirements: a)

No surface defects that could affect the satisfactory performance in serve should be tolerated.

b)

The capacitor voltage divider should be replaced if there is any evidence of leakage.

4.4.5 Winding resistance measurement of electromagnetic units Winding resistance measurement of electromagnetic units should include the following: a)

Measurement should be performed for all windings of intermediate transformers, compensation reactors and dampers. The resistance of the primary winding of intermediate transformers and compensation reactor windings can be measured together when possible.

b)

For the resistance of intermediate transformers and compensation reactor windings, relevant deviation should be within ±10% of the factory test value at the same temperature. For dampers, the relevant deviation should be within ±15% of the factory test value.

4.4.6 Insulation resistance measurement of each component of electromagnetic units Insulation resistance between terminals of intermediate transformer secondary windings and earth, insulation resistance of intermediate transformer primary windings to earth, insulation resistance of compensation reactor windings to earth, as well as insulation resistance of damper to earth should be tested and meet the requirements of manufacturer and user. NOTE—Different manufacturers and users may give different suggested values of test voltage and insulation resistance. In the Chinese case, the test voltage is 2500 V, and insulation resistance should not be lower than 1000 MΩ.

4.4.7 Connection check between components of electromagnetic units Connection between components of electromagnetic units should be checked and should conform to the nameplate. 4.4.8 Tightness of electromagnetic units No surface defects that could affect the satisfactory performance in service should be tolerated.

10

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

4.4.9 Accuracy checks (determination of error) Accuracy checks should include the following: a)

The tests should be performed on all gate metering voltage transformers.

b)

Error measurement should not be replaced by voltage ratio measurement methods with a voltage ratio tester.

c)

A polarity check should be performed simultaneously with error measurement, and the labeling of each connecting terminal should be checked.

d)

Both difference methods and voltage coefficient measurement methods can be applied to accuracy tests.

e)

Tests should be performed on each secondary winding separately except for residual windings. The access load of tested windings should be between 25% ~ 100% of rated load, and for other windings the load should be between 0% ~ 100% of rated load. The power factor of the secondary load should be considered as 1 if there is not any other special requirement given by the user.

f)

Tests for the metering winding and the measuring winding (0.2 level and 0.5 accuracy level) should be performed at 80%, 100%, and 120% of rated voltage or as agreed upon between the manufacturer and user.

g)

Error characteristic measurement of protection windings should be performed at 2%, 5%, and 100% of rated voltage.

h)

During measurement, the layout of a high-voltage lead should be as close as possible to actual operation condition.

NOTE—This test was performed at 80%, 100%, and 105% of rated voltage in the Chinese example.

4.4.10 Damper check The damper check should include the following: a)

Excitation characteristics and test methods of dampers should follow the requirements of the manufacturers.

b)

Check whether the damper has been connected with the specified secondary winding terminal correctly.

4.4.11 Low-frequency withstand voltage test on capacitor voltage dividers (optional test) If needed, the low-frequency withstand voltage test on capacitor voltage dividers should include the following: a)

80% of the factory test voltage value should be applied on capacitor voltage dividers and maintained for 1 min.

b)

The capacitance and tanδ should be measured before and after the low-frequency withstand voltage test. There should be no significant changes.

11

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

4.5 Bushing-type CTs 4.5.1 On-site acceptance tests for bushing-type CTs On-site acceptance tests for bushing-type CTs include the following: a)

Insulation resistance tests

b)

Resistance measurements

c)

An applied voltage test on secondary windings

d)

Determination of error and polarity check

e)

An excitation test

4.5.2 Insulation resistance tests Insulation resistance between each secondary winding and earth and on secondary windings should be tested and should meet the requirements of the manufacturer and user. NOTE—Different manufacturers and users give different suggested values of test voltage and insulation resistance. In the Chinese example, the test voltage is 2500 V and the insulation resistance should not be lower than 1000 MΩ.

4.5.3 Resistance measurements Refer to 8.5 of IEEE Std C57.13-2008 for resistance measurements, with the following addition: a)

Compare the dc resistance of secondary winding with the factory test result when converted to the same temperature. The difference should not exceed 10%.

b)

For CTs with the same batch, model, and specification, the difference of their tested value of the secondary winding dc resistance should not exceed 10%.

4.5.4 Applied voltage tests on secondary windings Refer to 7.3 of IEEE Std C57.13.5-2009 for applied voltage tests on secondary windings. 4.5.5 Determination of error and polarity check The determination of error and polarity should include the following: a)

The CT used for gate measurement should perform the determination of error test.

b)

The polarity check should be performed simultaneously with determination of error, or dc method should be adopted. The terminal markings should be checked.

c)

For multi-transformation ratio windings, measure only the full range error of one transformation ratio and verify the error at 20% Ir point of the other voltage ratios. The transformation ratio of all windings should conform to the value given on the nameplate.

12

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

d)

For determination of error, the direct method (difference value method) should apply. If the applied current cannot reach the specified value, the indirect method can be adopted with the precondition that the error at 20% Ir point has been measured by direct method.

4.5.6 Excitation tests Refer to Clause 9 of IEEE Std C57.13.1-2006 for excitation tests, with the following additions: a)

The test should be carried out when the CT excitation characteristic is required by the relay protection.

b)

If the CT is multi-tap type, the measurement can be taken at the tap in use or the tap with the minimum transformation ratio. The result should meet the requirement specified by manufacturer and user.

c)

If the test voltage applied is greater than the winding allowable value (4.5-kV peak), the frequency of the test power supply should be reduced.

4.6 Gas-insulated switchgear The following subclauses based on IEEE Std C37.122-2010 establish the requirements for testing the gasinsulated switchgear after installation, assembly, and wiring in the field and before placing it into commercial service. For details, refer to Annex B of CIGRE WG B3.29 technical brochure [B1] as a practical example based on the experiences in China, and this standard’s bibliography (Annex E) for standards and publications that may be useful in implementing this IEEE guide. 4.6.1 Mechanical tests: leakage Refer to 9.1 of IEEE Std C37.122-2010 for mechanical leakage tests, with the addition that the leakage rate should conform to following value depending on the agreement between manufacturer and user (see IEC 62271-1:2011 and [B28]): leakage rate < 0.5%/year. 4.6.2 Mechanical tests: gas quality (moisture, purity, and density) Refer to 9.2 of IEEE Std C37.122-2010 for mechanical gas quality (moisture, purity, and density) tests, with the following additions: The moisture content should be determined according to IEEE Std C37.122-2010, IEEE Std C37.100.12007, IEC 62271-203: 2003, and IEC 62271-1: 2011. Users applying equipment 1000 kV and above should refer to CIGRE WG B3.29 [B1]: the following more strict moisture value criteria is recommended, since the moisture value corresponds to 876 µL/L at 0.5 MPa and 568 µL/L at 0.7 MPa. The moisture value is as follows: 

< 150 µL/L

for apparatus with current-interrupting duties



< 500 µL/L

for apparatus without current-interrupting duties 13

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

CIGRE WG B3.29 [B1] indicates the variation of the criteria between 250 µL/L, 300 µL/L, and 500 µL/L for apparatus without current-interrupting duties [B30]. The value of 500 µL/L is recommended as a minimum requirement [B28] and as a reliable criterion that has been verified via the field experiences over 30 years in Japan [B30]. The density of the gas should be measured and verified to be in accordance with the manufacturer’s nominal rated filling requirements. 4.6.3 Electrical tests: continuity, conductivity, and resistivity Refer to 9.3 of IEEE Std C37.122-2010 for electrical continuity, conductivity, and resistivity tests, with the following addition: for UHV equipment and system, the resistance should be measured by the dc voltage application and evaluated as follows [B2], [B28]: a)

Current I during measurement: from 300 A to rated normal current.

b)

The measured resistance value should be 1.2 × Ru or lower, where Ru is defined as resistance measured in the factory test or before the temperature-rise test in the factory.

4.6.4 Electrical tests: low-frequency ac voltage withstand (Annex B.2) Refer to 9.4 of IEEE Std C37.122-2010 for electrical low-frequency ac voltage withstand tests, with the following additions. The example of voltage levels and durations of conditioning voltage application is introduced in Figure B.1 of Annex B. The conditioning voltage application and the 1-min low-frequency voltage withstand test should be performed after the gas-insulated switchgear has been completely installed and the gas compartments have been filled to the manufacturer’s recommended nominal rated fill density. A conditioning test before “ac voltage test followed by PD test” is effective to suppress breakdowns due to the presence of metallic particles, if any. Any additional tests may be performed subject to the user-manufacturer agreement. For UHV equipment and systems, the main circuits may be tested as follows (see IEC 62271-1:2011, [B1], [B2], and [B3]: a)

AC voltage test followed by PD test

b)

Three impulses at test voltage of 80% of LIWV (each polarity)

As an another option, elimination of the on-site voltage test is possible under the agreement between the manufacturer and user if a special care is taken in the equipment design and in the quality control during transportation and on-site assembly in order to keep the same dielectric integrity checked by the test in the factory. In this case, the test voltage and procedure are as follows [B1] and [B3]: c)

AC voltage test (1 pu-1 h) with PD test (1 pu: operating voltage and commissioning test voltage)

14

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

4.6.5 Electrical tests: low-frequency ac voltage withstand requirements and conditions (Annex B.2) Refer to 9.5 of IEEE Std C37.122-2010 electrical low-frequency ac voltage withstand requirements and condition tests. 4.6.6 Electrical tests: low frequency ac voltage withstand configurations and applications (Annex B.2) Refer to 9.6 of IEEE Std C37.122-2010 for electrical low-frequency ac voltage withstand configuration and application tests. 4.6.7 Electrical tests: assessment of the ac voltage withstand test (Annex B.2) Refer to 9.8 of IEEE Std C37.122-2010 for assessment of the ac voltage withstand. 4.6.8 Electrical tests: tests on auxiliary circuits Refer to 9.9 of IEEE Std C37.122-2010 for tests on auxiliary circuits, with the following addition: the circuits should be checked by withstand voltage test or by insulation resistance measurement as follows (see IEC 62271-1:2011, [B2], and [B29]): a)

Withstand test voltage 2 kV (1 min)

b)

Insulation resistance of the circuits > 2 MΩ

4.6.9 Mechanical and electrical functional tests: checks and verifications Refer to 9.10 of IEEE Std C37.122-2010 for mechanical and electrical functional checks and verifications. 4.6.10 Mechanical and electrical tests: documentation Refer to 9.11 of IEEE Std C37.122-2010 for mechanical and electrical test documentation.

4.7 Air-insulated grounding switches 4.7.1 On-site acceptance tests for air-insulated grounding switches On-site acceptance tests for air-insulated grounding switches include the following: a)

Appearance check

b)

Dielectric tests on control and auxiliary circuits

c)

Mechanical test

15

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

4.7.2 Appearance check Refer to 7.5 of IEC 60694:2002 for appearance check requirements. 4.7.3 Dielectric tests on control and auxiliary circuits Refer to 7.2 of IEC 60694: 2002 for dielectric tests on control and auxiliary circuits with the following additions: a)

Insulation resistance, measured before applying the voltage withstand test, should be greater than 2 MΩ.

b)

Control and auxiliary circuits should withstand power frequency voltage at 2 kV for 1 min. The value of insulation resistance should not significantly drop after the voltage withstand test.

4.7.4 Mechanical test Refer to 7.6 of IEC 62271-102: 2001 for the mechanical test.

4.8 Air-insulated disconnecting switches 4.8.1 On-site acceptance tests for disconnecting switches On-site acceptance tests for disconnecting switches should include the following: a)

A dielectric test on auxiliary and control circuits

b)

Measurement of the resistance of the main circuit

c)

Design and visual inspection

d)

A mechanical test

4.8.2 Dielectric tests on control and auxiliary circuits Refer to 7.2 of IEC 60694:2002 for dielectric tests on control and auxiliary circuits, with the following additions: a)

Insulation resistance, measured before applying the voltage withstand test, should be greater than 2 MΩ.

b)

Control and auxiliary circuits should withstand power frequency voltage at 2 kV for 1 min. The value of insulation resistance should not significantly drop after the voltage withstand test.

4.8.3 Measurement of the resistance of the main circuit Refer to 6.4.1 of IEC 60694: 2002 for measurement of the resistance of the main circuit specifications.

16

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

4.8.4 Design and visual inspection Refer to 7.5 of IEC 60694: 2002 for design and visual inspection specifications. 4.8.5 Mechanical test Refer to 7.6 of IEC 62271-102: 2001 for mechanical test specifications.

4.9 Bushings 4.9.1 On-site acceptance tests for UHV bushings (oil-impregnated paper-insulated bushings) On-site acceptance tests for UHV bushings should include the following: a)

Visual inspection

b)

Tanδ and capacitance measurement

c)

Tap withstand voltage

4.9.2 Visual inspection Refer to 9.10 of IEC 60137:2009 for visual inspection specifications. 4.9.3 Tanδ and capacitance measurement Refer to 9.1 of IEC 60137: 2009 for tanδ and capacitance measurement specifications, with the following additions: a)

After installation of the transformer and reactor bushings, tanδ and capacitance of the insulation should be measured at 10 kV while voltage tap (if any) should be short-circuited with the test tap.

b)

The deviation between measured capacitance value and nameplate value should be lower than ±5%, and the value of tanδ should have no obvious difference from the factory test results.

4.9.4 Tap withstand voltage Refer to 7.2.4 of IEEE Std C57.19.00-2004 for tap withstand voltage specifications. NOTE—For voltage tap, different manufacturers may give different suggested values of test voltage. It is advised to refer to the product specification or consult the manufacturer before testing.

17

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

4.10 MOSAs 4.10.1 On-site acceptance tests for MOSAs For the procedure followed for field tests, the test method should refer to same kind of tests described in relevant publications, such as IEEE Std C62.11-2005. The test methods and their descriptions listed below are applicable for MOSAs. a)

Insulation resistance test of MOSAs

b)

Insulation resistance test of the bottom of the MOSAs

c)

Leakage current test

d)

Check of appearance

e)

Check of monitoring devices

4.10.2 Insulation resistance test of MOSAs The insulation resistance should be tested at 5000 V and the tested insulation resistance value should not be lower than 2500 MΩ. 4.10.3 Insulation resistance test of the bottom of the MOSAs The insulation resistance should be tested at 2500 V and the tested insulation resistance value should not be lower than 2000 MΩ. 4.10.4 Leakage current test Total leakage current and resistive leakage current should be measured under operation voltage. The measured values should meet the requirements of the manufacturer and user. 4.10.5 Check of appearance The appearance of MOSA units should show no visible damage. The MOSAs appearance after installation, such as the piling order of MOSA units and the shield ring, etc., should be according to the drawing and instruction manual of the manufacturer. 4.10.6 Check of monitoring devices There should be no damage of the appearance or the script clear and the gauge needle should not be pointing to zero. The initial number of the counter should be recorded. The lowest current of MOSAs under the operating voltage should be confirmed by the graduation of the current monitoring device.

18

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

4.11 Suspension insulators and post insulators For field tests, the test method should refer to same kind of tests described in relevant publications, such as IEC 60383-1:1993. The test methods and their descriptions listed below are applicable for suspension insulators and post insulators. 4.11.1 On-site acceptance tests of suspension insulators On-site acceptance tests of suspension insulators should include the following: a)

The insulation resistance should be tested at 5000 V. The tested value of insulation resistance of each piece of suspension insulator should not be lower than 5000 MΩ before installation.

b)

For the ac voltage withstand test, the test voltage for the suspension insulator is 60 kV. For the test method, refer to 14.1 of IEC 60383-1:1993.

4.11.2 On-site acceptance tests of post insulators The insulation resistance measurement should be performed on a transportation unit with 5000 V before installation. The value of the measured insulation resistance should not be lower than 5000 MΩ. NOTE—There is no detailed requirement about insulation resistance and ac voltage withstand tests in IEEE or IEC standards for UHV on-site acceptance tests. The value provided here is based on the experiences in China.

4.12 Insulating oil Test requirements of insulating oil filling into electrical equipment should be as per Table 1. Table 1 —Requirements of insulating oil No.

Items

Requirements

1

Visual examination

Transparent, inclusion-free, no suspended matter

2

Granularity in oil

Granularity (5 µm ~ 100 µm) ≤ 1000/100 mL Granularity (> 100 µm) None

3

Dielectric strength, kV

≥70（2.5 mm gap, spherical electrode）

4

Dissipation factor, 90 ℃, %

Before filling into equipment ≤ 0.5 After filling into equipment ≤ 0.7

5

Water content, 50 ℃,mg/kg

≤ 10

6

Total dissolved gas, %

≤ 0.5

7

DGA

Refer to relevant subclauses of this guide

NOTE—The maximum value of dissipation factor is 0.05% (25 ℃) and 0.3% (100 ℃) in IEEE Std C57.106™-2006 [B28]. Because of the large quantity of oil in UHV transformers and shunt reactors, it may be difficult to conduct on-site treatment. According to the Chinese experience, dissipation factor values less than 0.5% (at 90 ℃) after filling oil into the equipment should meet the insulation requirements.

19

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

5. System commissioning 5.1 General System commissioning is a necessary characteristic inspection of the new system before it is put into operation. The commissioning test in this clause is based on engineering experience which was performed to help ensure the stable and safe operation of the newly constructed UHV system. The system commissioning test specifies the test items, requirements, and evaluation criteria for the commissioning of UHV ac transmission systems. To help ensure the safety of the system and equipment during commissioning, simulation and analysis should be carried out before the actual commissioning test, including power flow and stability calculation and electromagnetic transient simulation. The system commissioning scheme formulations should take simulation results into account. It should include test items, objectives, contents, procedures, the operation mode of the power system, and safety measures. The measurement scheme should be formulated based on simulation results and the commissioning scheme. It should include the objectives, contents, conditions, instruments, methods, and safety measures. The system commissioning schedule should be formulated by the dispatching department according to the system commissioning scheme. It should include the operating authorization, incident management principle, and protection operation including temporary relay settings.

5.2 System commissioning items Items of system commissioning are listed in Table 2. Relevant measurement items are conducted during the process of system commissioning.

20

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

Table 2 —System commissioning items No. 1 2 3 4 5 6 7 8 9

System commissioning items Measurement of UHV transmission line parameters at rated power frequency Test of UHV power transformer with current increasing from zero Test of UHV ac transmission line with current increasing from zero Test of UHV power transformer with voltage rising from zero Test of UHV ac transmission line with voltage rising from zero Switching on/off test of no-load UHV power transformer Switching on/off test of UHV ac no-load transmission line Ring closing ( interconnection )/ Ring opening ( splitting ) test of UHV system Induced current and induced voltage test of the double circuit/ multi-circuit UHV ac transmission lines on the same tower Switching on/off test of tertiary connected reactor Switching on/off test of tertiary connected capacitor Artificial single phase to ground fault test System dynamic disturbance test Normal operation test

Note * * * * ** ** ** **

10 ** 11 ** 12 ** 13 ** 14 ** * The test system should be composed of the selected generator, substations, and transmission lines, which are completely isolated from the operating system electrically. ** The test should be performed in the operating system.

5.2.1 Measurement of UHV transmission line parameters at rated power frequency The accuracy of UHV transmission line parameters at rated power frequency is very important to the simulation analysis of the system commissioning. These parameters provide the basis of short-circuit current and load flow distribution calculations and choice of reasonable operation mode. The measurement can verify the insulation and the phase of the newly constructed UHV transmission lines before operation. The measurement results can help analyze the discrepancy between the measurement parameters and design parameters and help form operational strategies. The test procedures are described as follows: 

The measurement can be carried out after all the work on the UHV transmission lines has been completed and the circuit breakers at both ends of UHV transmission lines, isolating switches of the UHV reactors, and grounding switches have all passed the acceptance inspection and are switched off.



The other transmission lines that are across or parallel with the UHV transmission lines are out of service.

The measurement contents are described as follows: 

Measurement of the induced voltage: Measure the amplitude and phase of induced voltage of phase to phase and phase to ground. The measured results are used to eliminate the error caused by induced voltage during parameter measurement and calculation.



Measurement of the insulation resistance: Measure the insulation resistance of phase to phase and phase to ground. Check the isolation of the UHV transmission lines and whether there are defects such as a short circuit between phase to ground or phase to phase, etc.



Measurement of the dc resistance: The dc resistance is usually obtained by using ammeter, voltmeter, or bridge method. The measuring instrument should be able to accurately measure the dc and ac component of the voltage and current.



Measurement of the positive sequence impedance: Connect the three-phase power supply at the rated power frequency to the measuring end of the UHV transmission line with the other end of the 21

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

test line putting on a three-phase short circuit. Measure the phase voltage, phase current, and power of each phase. Calculate the arithmetical average value of the measured voltage and current and calculate the algebraic sum of the three-phase power, which is displayed on the low power factor wattmeter. The positive sequence impedance per kilometer per phase is calculated according to the measurement results. It can be verified in the current raising from a zero test of the UHV ac transmission line and the manual single phase to ground fault test. 

Measurement of the zero-sequence impedance: Connect the single-phase power supply at the measuring end of the UHV transmission line with three phase circuits connected together and with the other end of the test line making a three-phase-to-ground short circuit. Measure the voltage, current and power. The zero sequence impedance per kilometer per phase is calculated using the measurement results. It can be verified in the manual single-phase-to-ground fault test.



Measurement of the positive sequence admittance: Connect the three-phase power supply at the measuring end of the UHV transmission line with the other end of the test line open. Measure three-phase voltage with a voltage transformer (VT) at the each end of the test line. Calculate the arithmetical average value of the measured phase voltage and current at both ends of the test line and calculate the algebraic sum of the three phase power, which is displayed on the low power factor wattmeter. The positive sequence admittance per kilometer per phase is calculated according to the measurement results. It can be verified in the test of a UHV ac transmission line with voltage rising from zero, a switching on/off test of the UHV ac no-load transmission line, and the manual single phase to ground fault test.



Measurement of the zero-sequence admittance: Connect the single-phase power supply at the head of the UHV transmission line with a three-phase short circuit and make a three-phase open circuit at the end of the test line. Measure the three-phase current at the head of the test line and the voltage of the head to the end of the test line. The zero sequence admittance per kilometer per phase is calculated according to the measurement results. It can be verified in the test of the UHV ac transmission line with voltage rising from zero, switching on/off test of UHV ac no-load transmission line, and the manual single phase-to-ground fault test.



Measurement of the phase to phase coupling capacitance: Connect the single-phase power supply to the test phase at the measuring end of the UHV transmission line with the other end of the test line making a three-phase open circuit. Measure the voltage and current of the test phase and the coupling current of the other two phases. The phase-to-phase coupling capacitance is calculated according to the measurement results. It can be verified in the test of the UHV ac transmission line with voltage rising from zero, the switching on/off test of the UHV ac no-load transmission line, and the manual single phase-to-ground fault test.



Measurement of the phase to phase mutual impedance: Add the single-phase power supply to the test phase at the head of the UHV transmission line and make a three-phase short circuit to ground at the end of the test line. Measure the voltage and current of the test phase and the induced voltage of the other two phases. The mutual impedance is calculated according to the measurement results. It can be verified in the test of the UHV ac transmission line with voltage rising from zero, switching the on/off test of UHV ac no-load transmission line, and the manual single phase-toground fault test.

NOTE—All the above measurement results should meet the design requirements of the project within specified tolerance as determined by the user.

5.2.2 Test of UHV power transformers with current increasing from zero This is a performance test on the UHV power transformer before it is put into operation. The aim is to verify the through-current capability of UHV equipment and the polarity and phase of the CT in a UHV

22

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

power transformer. Also, it can be used to verify whether the relevant relay protections work under normal conditions. This test should be performed according to the field conditions and the needs of the user. The test procedures are described as follows: 

Select a generator as the test power supply and connect it to the UHV power transformer. Make sure the selected generator capacity meets the test requirements.



Install the short-circuit line at the side of current increasing from zero (not the side of the power supply) of the UHV power transformer. Select its current carrying capacity according to the calculated value, which should be no less than two times of the calculated value.



Adjust the relevant protection settings according to the system commissioning schedule.



The test of current increasing from zero on the primary side (or secondary side) and the tertiary side of the UHV power transformer should be carried out in the isolated system.

The measurement contents are described as follows: 



Test of current increasing from zero on the primary side (or secondary side) of the UHV power transformer. 

Measure the short-circuit impedance of the primary to secondary windings of the UHV power transformer.



Measure the polarity and phase of the secondary circuit of the CT of the UHV power transformer.



Measure the infrared temperature of the bus, conducted connectors, circuit breakers, isolating switches, etc.



Measure the vibration and audible noise of the UHV power transformer when the short-circuit current is close to the rated value.

Test of current increasing from zero on the tertiary side of the UHV power transformer. 

Measure the short-circuit impedance of the primary to secondary (or primary to tertiary) windings of the UHV power transformer.



Measure the polarity and phase of the secondary circuit of the CT of the UHV power transformer.



Measure the infrared temperature of the bus, conducted connectors, circuit breakers, isolating switches, etc.



Measure the vibration and audible noise of the UHV power transformer when the short-circuit current is at the rated value.

NOTE—All the above measurement results should meet the design requirements of the project within specified tolerance as determined by the user.

23

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

5.2.3 Test of UHV ac transmission lines with current increasing from zero This is a performance test on the UHV ac transmission line before it is put into operation. The aim is to verify the load-carrying capability of UHV equipment and the polarity and phase of the CT in UHV power transformer and UHV transmission lines. Also, it can be used to verify whether the relevant relay protections work in normal conditions. This test should be performed according to the field condition and the needs of the user. The test procedures are described as follows: 

The test should be carried out in the isolated system.



Select a generator as the test power supply and connect it to the UHV transmission lines. Make sure the selected generator capacity meets the test requirement.



Install the short-circuit line at the remote end of the UHV transmission line. Select its currentcarrying capacity according to the calculated value, which should be no less than two times the calculated value.



Adjust the relevant protection settings according to the system commissioning schedule.

The measurement contents are described as follows: 

Measure the polarity and phase of the secondary circuit of the CT of the UHV power transformer.



Measure the infrared temperature of the bus, conducted connectors, circuit breakers, isolating switches, etc.

NOTE—All the above measurement results should meet the design requirements of the project within specified tolerance as determined by the user.

5.2.4 Test of UHV power transformer with voltage rising from zero This is a performance test on the UHV power transformer before it is put into operation. The aim is to verify the insulation of the UHV equipment, mainly the UHV transformer, to verify the voltage phase and phase sequence of the CVT at each side of the UHV power transformer. Also, it can be used to verify the operating characteristics of the UHV power transformer, such as excitation characteristics, no-load loss, harmonic vibration, audible noise, temperature rising, insulation oil, etc. Also, it can be used to verify whether the relevant relay protections work in normal conditions. This test should be performed according to the field conditions and the needs of user. The test procedures are described as follows: 

The test should be carried out in the isolated system.



Select a generator as the test power supply and connect it to the UHV power transformer. Make sure the selected generator capacity meets the test requirements.



Adjust the relevant protection settings according to the system commissioning schedule.

24

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

The measurement contents are described as follows: 

Measure the volt-ampere characteristics of the UHV power transformer. A high-precision CT should be installed for the measurement. Measure the open-circuit excitation curve of the UHV power transformer; Measure the open-circuit current and loss of the UHV power transformer when the voltage equals 1.0 Un or 1.05 Un（Un = 1050/ 3 kV.



Measure the harmonic spectrum of the three-phase voltage and current of the primary and secondary sides of the UHV power transformer.



Measure the vibration of the UHV power transformer during voltage rising.



Measure the audible noise of the UHV power transformer during voltage rising. Measure the background noise level before the transformer is energized. Measure the audible noise level of the equipment after the transformer is energized at rated voltage.



Measure the amplitude, phase angle, and phase sequence of the secondary voltage of the CVT at each side of UHV power transformer.

NOTE—All the above measurement results should meet the design requirements of the project within specified tolerance as determined by the user.

5.2.5 Test of UHV ac transmission line with voltage rising from zero This is a performance test on the UHV ac transmission line before it is put into operation. The aim is to verify the insulation of UHV lines and circuit breakers to verify the polarity and phase of the CT of the UHV shunt reactor, transformer, and its tertiary connected reactor. Also, it can be used to verify the voltage amplitude, phase angle, and phase sequence of the CVT of UHV lines. This test should be performed according to the field condition and the needs of the user. The test procedures are described as follows: 

The test should be carried out in the isolated system.



Select a generator as the test power supply and connect it to the UHV transmission lines. Make sure the selected generator capacity meets the test requirements.



Make sure the selected generator in the isolated system will not induce self-excitation during the test based on the analysis.



Switch on/off the tertiary connected reactors of the UHV power transformer according to the calculation result.



Adjust the relevant protection settings according to the system commissioning schedule.

The measurement contents are described as follows: 

Measure the amplitude, phase angle, and phase sequence of the current of the UHV transmission lines.



Measure the amplitude, phase angle, and phase sequence of the voltage of the UHV transmission lines. 25

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above



Measure the voltage, current, and reactive power of the UHV shunt reactor and the tertiary connected reactors.



Measure the vibration of the UHV power transformer during voltage rising.



Measure the audible noise of the UHV power transformer during voltage rising. Measure the background noise level before the transformer is energized. Measure the audible noise level of the equipment after the transformer is energized.



Measure the volt-ampere characteristics of the UHV shunt reactor. A high-precision CT should be installed for the measurement.



Measure the charging power during the process of voltage rising from zero in UHV transmission lines.

NOTE—All the above measurement results should meet the design requirements of the project within specified tolerance as determined by the user.

5.2.6 Switching on/off test of no-load UHV power transformer Because of the nonlinear excitation characteristics of the UHV power transformer core and the periodical changing of the iron core, harmonics may cause high-amplitude resonance overvoltage while switching on/off no-load transformers, and the inrush current can be harmful to the relevant relay protections during the switching. This test aims to verify the function of the circuit breaker to switch on/off the UHV transformer under operating voltage and to measure the overvoltage and inrush current during the switching. Also, the function of the UHV transformer protection relay can also be verified. It is usually performed for newly constructed UHV transformers. For UHV projects for which the test of voltage rising from zero cannot be performed, this switching on/off test can also verify the UHV transformer operating characteristics and the voltage phase and phase sequence of the CVT at each side of the UHV power transformer. Also, it can be used to verify the voltage phase and phase sequence of the CVT of UHV lines. This test should be carried out respectively by the circuit breakers on the primary and secondary sides of the UHV power transformer. The test procedures are described as follows: 

Adjust the tap position at the secondary side of the UHV power transformer according to the commissioning schedule.



Switch on/off the tertiary connected reactors of the UHV power transformer based on the analysis.



Block the single-phase automatic reclosing function of the UHV transmission lines.



Adjust the relevant protection settings according to the system commissioning schedule.



The test can be carried out by switching on/off circuit breakers at primary and secondary sides of the UHV power transformer five times for each side.

The measurement contents are described as follows: a)

Measure the overvoltage at each side of the UHV power transformer.

b)

Measure the inrush current when the UHV no-load transformer is put into operation by switching on/off the circuit breakers on the primary side or the secondary side. 26

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

NOTE—All the above measurement results should meet the design requirements of the project within specified tolerance as determined by the user.

c)

Measure the dissolved gases in oil of the UHV power transformer.

NOTE—Measurement results should meet the requirements of IEEE Std C57.104™-2008.

5.2.7 Switching on/off test of UHV ac no-load transmission line This test aims to verify the function of circuit breakers to switch on/off UHV lines, to measure the overvoltage during no-load line switching, and to measure the impact on the system operating voltage and reactive power. Also, the function of UHV line relay protection devices can be verified. And for the UHV projects where the test of voltage rising from zero cannot be performed, this switching on/off test can also verify the UHV line insulation and the voltage phase and phase sequence of CVT at each side of UHV power transformer. This test can also verify the effectiveness of the overvoltage suppression measures, such as the UHV shunt reactor or the closing resistor of the circuit breaker. This test should be carried out respectively by the circuit breakers at each end of the UHV transmission line. The test procedures are described as follows: 

Adjust the tap position at the secondary side of the UHV power transformer according to the system commissioning schedule.



Switch on/off the tertiary connected reactors of the UHV power transformer based on the analysis.



Block the single-phase automatic reclosing function of UHV transmission lines.



Adjust the relevant protection settings according to the system commissioning schedule.



Tests can be carried out by switching on/off the circuit breakers at each end of the no-load UHV transmission line three times.



Put the single-phase automatic reclosing function of the UHV transmission lines into service. Switch off the circuit breaker of A, B, or C phase individually to test single-phase reclosing.

The measurement contents are described as follows: a)

Measure the transient voltage and current of the surge arrester when switching on/off UHV no-load transmission lines. Measure the overvoltage of UHV transmission lines and the neutral point of the UHV shunt reactor to earth.

b)

Measure the charging current of transmission lines.

c)

Measure the induced voltage of the UHV earthing lines.

NOTE—All the above measurement results should meet the design requirements of the project within specified tolerance as determined by the user.

d)

Perform a DGA test of the UHV power transformer, UHV shunt reactor, and neutral point connected reactor

NOTE—Measurement results should meet the requirements of IEEE Std C57.104-2008.

27

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

5.2.8 Ring closing (interconnection)/ring opening (splitting) test The newly constructed UHV power transformer and transmission lines are required to be put into the operating system by a synchronization device of the circuit breaker. The process of the UHV equipment being put into or removed from the operating system is called ring closing (interconnection)/ring opening (splitting). Ring closing (interconnection)/ring opening (splitting) will impact the operating system, depending on the differences of voltage and phase angle at each side of the operating point, etc. This is a common operation in the power system and is necessary to verify the impact of ring closing (interconnection)/ring opening (splitting) on power, frequency, and voltage of the operating system. This test should be performed when the UHV transmission lines connect two separate grids, and it should be carried out respectively by the circuit breakers on the primary and secondary sides of the UHV power transformer and the circuit breakers at each end of the UHV transmission line. The test procedures are described as follows: 

Tests can be carried out by switching the circuit breaker at each end of the UHV transmission lines or at the secondary side of the UHV power transformer. If the system to be interconnected is weak with low short-current capacity, it is suggested that closing (interconnection)/opening (splitting) test be carried at the secondary side of the UHV power transformer.



The tertiary connected reactors of the UHV power transformer should be switched on/off based on the analysis.



Adjust the relevant protection settings according to the system commissioning schedule.



Before the actual closing of the circuit breaker, a virtual synchronization ring closing (interconnection) by switching the circuit breakers at each end of UHV transmission lines or at the secondary side of UHV power transformer should be taken.

The measurement contents are described as follows: 

Measure the difference of the voltage amplitude, phase angle, and frequency at each side of splitting point or interconnection point.



Measure the power of the UHV transmission lines.

NOTE—All the above measurement results should meet the design requirements of the project within the specified tolerance as determined by the user.

5.2.9 Induced current and induced voltage test of the double-/multi-circuit UHV ac transmission lines on the same tower This test is to verify the switching capability of grounding switches and to measure the voltage and current induced on an out-of-service transmission line by other on-load circuits that share the same transmission towers. The measurement result can be used to obtain the coupling characteristics among UHV lines. This test should be performed for each newly constructed double-/multi-circuit UHV ac transmission line on the same tower. The test procedures are described as follows: 

Put one of the double-/multi-circuits on the same towers into service and others out of service.

28

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above



Adjust the relevant protection settings according to the system commissioning schedule.



Tests can be carried out by switching on/off the grounding switches, respectively, once at each end of the UHV transmission lines that are out of service.

The measurement contents are described as follows: 

Measurement should not be taken under rainy conditions.



Measure the phase-to-earth voltage at each end of transmission lines that are out of service (grounding switches are off).



Measure the current at each end of transmission lines that are out of service (grounding switches are on).

NOTE—All the above measurement results should meet the design requirements of the project within the specified tolerance as determined by the user.

5.2.10 Switching on/off test of tertiary connected reactor Reactors connected to the tertiary side of the UHV power transformer by circuit breakers are used for voltage regulation and reactive power compensation. Because of the large capacity of reactors, their switching can cause high transient overvoltage and large fluctuation on steady-state voltage. This test aims to verify the capability of circuit breakers to switch on/off reactors under operating voltage, to measure the overvoltage at the tertiary side of the UHV power transformer, and to measure the impact on the system operating voltage. The phase and the polarity of voltage and current of relay protection devices for reactors can be verified as well. This test should be carried out for each circuit breaker. The test procedures are described as follows: 

Adjust the relevant protection settings according to the system commissioning schedule.



The test can be carried out by switching on/off the tertiary connected reactor three times.

The measurement contents are described as follows: 

Measure the voltage and current at each side of the UHV power transformer.



Measure the voltage and current of the tertiary connected reactor and its neutral point.



Measure the switching overvoltage at the tertiary side of the UHV power transformer.

NOTE—All the above measurement results should meet the design requirements of the project within specified tolerance as determined by the user.

5.2.11 Switching on/off test of tertiary connected capacitor Capacitors connected to the tertiary side of the UHV power transformer by circuit breakers are used for voltage regulation and reactive power compensation. Because of the large capacity of the capacitors, their switching can cause large inrush transient currents that are very important to check the performance of the capacitor and its circuit breakers. This test aims to verify the capability of circuit breaker to switch on/off

29

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

the capacitor, to measure the inrush transient current when switching on the capacitor, to measure the impact on the system operating voltage, and to verify the phase and the polarity of the voltage and current of relay protection devices for capacitors. This test should be carried out for each circuit breaker. The test procedures are described as follows: 

Adjust the relevant protection settings according to the system commissioning schedule.



The test can be carried out by switching on/off the tertiary connected capacitor three times.

The measurement contents are described as follows: 

Measure the voltage and current at each side of the UHV power transformer.



Measure the voltage and current of the tertiary connected capacitor and its neutral point.



Measure the switching overvoltage at the tertiary side of the UHV power transformer.

NOTE—All the above measurement results should meet the design requirements of the project within specified tolerance as determined by the user.

5.2.12 Artificial single phase-to-ground fault test The single phase-to-ground fault occurs most frequently among all line faults in power grids. UHV transmission lines have the single phase automatic reclosing function installed, and the auto reclosing time setting depends on the secondary arc current and the recovery voltage after the fault. It is set according to the simulation results and design parameters of the UHV transmission line. This test aims to verify the relay protection and single-phase reclosing performance of the UHV transmission lines and the effect of a neutral point connected reactor of a UHV shunt reactor on restraining secondary arc current. The test procedures are described as follows: 

The installation and commissioning of manual grounding devices should be completed during the maintenance of transmission lines.



System operation mode and safety precautions should meet the requirements of the system commissioning schedule.



Adjust the relevant protection settings according to the system commissioning schedule.



The test can be carried out by manual single-phase temporary short circuits grounding.

The measurement contents are described as follows: a)

Measure the steady-state voltage and current, active power, reactive power, and frequency of the operating system before and after the test.

b)

Measure the short-circuit current at the single phase-to- ground fault point.

c)

Measure the secondary arc current of the non-fault phase.

d)

Measure the recovery voltage of the UHV transmission line during the short-circuit fault. 30

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

e)

Measure the operating time of protection.

f)

In order to measure the transient response characteristics of the UHV CVT, measure the secondary voltage of the CVT on UHV transmission lines and the voltage of the bushing tap of the UHV shunt reactor. Check the difference between them.

g)

Measure the voltage and current of the reactor connected at a neutral point of the UHV shunt reactor.

h)

Measure the transient voltage of the UHV bus, transformer, shunts reactor, and the tertiary connected capacitor or reactor.

i)

Measure the transient voltage and current of the surge arresters of UHV transmission lines.

j)

Measure the induced voltage at the insulation end of UHV ac overhead earthing lines. Measurement should not be taken under rainy conditions.

NOTE—All the above measurement results should meet the design requirements of the project within specified tolerance as determined by the user.

k)

Record the atmosphere conditions of the test location such as wind speed, temperature, humidity, etc.

l)

Perform a DGA test of the UHV transformer, UHV shunt reactor, and the neutral point connected reactor.

NOTE—Measurement results should meet the requirements of IEEE Std C57.104-2008.

5.2.13 System dynamic disturbance test During UHV system operation, incidents such as line trip, generator trip, or a fault on transmission lines may occur and cause disturbance to the power, frequency, and voltage. Before system commissioning, simulation studies should be carried out under various abnormal conditions to assess the dynamic characteristic and the capability of the anti-disturbance of the UHV system. Disturbance tests such as tripping the generator or transmission line should be performed to verify the simulation results according to the measurement data. This could also provide operating data and experience for the dispatching center and help to improve the accuracy of the simulation studies. This test should be performed for the newly constructed UHV projects or UHV lines interconnecting two grids. The test procedures are described as follows: 

System operation mode and safety precautions should meet the requirements of the system commissioning schedule.



The test can be carried out by tripping a generator, transmission line, etc.

The measurement contents are described as follows: 

Measure the voltage and current at each end of the UHV transmission line.



Measure the system frequency, active power, and reactive power of the UHV transmission line and other relevant lines. 31

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

NOTE—All the above measurement results should meet the design requirements of the project within specified tolerance as determined by the user.

5.2.14 Normal operation test The UHV project has characteristics of long distance and large power transmission capacity compared with EHV transmission lines. This test aims to verify the operating characteristics of equipment under normal operation load. The harmonic level of the UHV power system and the surrounding environment of the UHV substation and line can be measured, which helps to collect on-site data and make full assessment on the UHV project. It also can verify control strategies of the UHV project such as power flow control and voltage control. It can provide operating data and experience for the dispatching center and help to verify the simulation results according to the measurement data to improve the accuracy of the simulation studies. The test procedures are described as follows: The UHV system should be subject to operate continuously under normal opeation load conditions. The measurement contents are described as follows: a)

Measure the voltage, current, harmonics, frequency, power angle, active power, and reactive power of the UHV transmission lines.

b)

Measure the vibration of the UHV power transformers and UHV shunt reactors. Multi-point vibration measurement should be taken for each transformer and reactor.

c)

Select a right location for the measurement of the sag along the UHV transmission line.

d)

Measure the infrared temperature of the bus, connectors, circuit breakers, isolating switches, etc.

e)

Measurement of the electric and magnetic field inside/outside the substation test should be carried out when the air humidity is not greater than 80%. For electric-field measurement, the system voltage should not be lower than the rated voltage, and for that of the magnetic field, the transmitted power should not be lower than 30% of the rated power.

f)

Measure the audible noise inside/outside the substation. Measurement should not be taken under rainy conditions or conditions when wind speed exceeds 5 m/s. Audible noise measurement inside and outside the substation should be taken under rated transformer load conditions. Audible noise measurement of the transmission line should be taken when the line voltage is not lower than the rated voltage.

g)

Measure the radio interference inside/outside the substation. Measurement should not be taken under rainy conditions. The location for measurement should be far away from transmission line transposition, intersection, and corner, and should be 10-km away from the ac substation or at least 2 km under special conditions.

h)

Measure the induced voltage at the insulation end of UHV ac overhead grounding lines. Measurement should not be taken under rainy conditions.

NOTE—All of the above measurement results should meet the domestic laws, regulations and standards relevant to environmental protection and occupational health as well as project design requirements.

i)

Perform a DGA test of the UHV power transformer, UHV shunt reactor and neutral connected reactor.

NOTE—Measurement results should meet the requirements of IEEE Std C57.104-2008.

32

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

Annex A (informative) On-site acceptance tests for UHV transformers—Practical examples based on the experiences in China The UHV transformer in China has two parts: the main part of the transformer and the regulating part. The schematic connection diagram of the UHV transformer in China is shown in Figure A.1. The main transformer can be connected to the voltage regulating and compensating transformer as a complete transformer and can also be used independently. The primary parameter of the transformer is described as follows: 

Type: single-phase, oil-immersed, auto transformer with no-load (de-energized) tap changer.



Rated power: 1000 MVA/ 1000 MVA/ 334 MVA.



Rated voltage: 1050/ 3 kV/ 525/ 3 kV/ 110 kV.



Tapped winding: 525/ 3 kV (tapping range ±5%).



Connection symbol: Ia0I0.



Rated frequency: 50 Hz.

Figure A.1—Schematic connection diagram of a UHV transformer in China

Tests of the main, voltage regulating, and compensating transformers are carried out individually and then on complete assembly. 

Main transformer tests include the following: 

Leak testing with pressure (tightness test)

33

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above





Winding resistance measurement



Ratio tests



Polarity check



Insulation resistance test between each winding to earth and between windings including bushing



Dissipation factor (tanδ) and capacitance measurement of the insulation system



Core and frame insulation check



Tests on bushing



Ratio and polarity check of bushing-type CTs



Insulating oil tests



DGA tests



No-load loss and excitation current measurements at reduced voltage



Applied voltage tests



IVPD



FRA



Short-circuit impedance measurement at reduced current

Voltage regulating transformer and compensating transformer tests include the following: 

Leak testing with pressure (tightness test)



Winding resistance measurement



Ratio tests



Polarity check



Insulation resistance test between each winding to earth and between windings including bushing



Dissipation factor (tanδ) and capacitance measurement of the insulation system



Core and frame insulation check



Tests on bushings



Ratio and polarity check of bushing-type CTs



Insulating oil tests 34

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above





DGA tests



Excitation (no-load) current measurement at reduced voltage



Applied voltage tests



IVPD



FRA



Short-circuit impedance measurement at reduced current

Tests for the main transformer with voltage regulating and compensating transformer together include the following: 

Ratio tests



Angular displacement check

A.1 Applied voltage test The applied voltage test was conducted as follows: a)

The test voltage was applied to the neutral point and 110-kV winding while the partial discharge was monitored.

b)

The test voltage value was 80% of the factory test value and the time duration was 1 min. The values are listed in Table A.1.

Table A.1—Test voltage of applied voltage test (kV) Voltage applied position neutral point 110kV winding

Factory test voltage 140 275

On-site acceptance test voltage 112 220

c)

The partial discharge was measured for one minute.

d)

The separate source ac voltage test was made with single-phase alternating voltage as nearly as possible on a sine-wave form and at a frequency not lower than 80% of the rated frequency. The peak value of voltage was measured. The peak value divided by 2 was equal to the test value.

e)

The test is successful if no collapse of the test voltage occurs.

35

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

A.2 Induced voltage test with partial discharge measurement (IVPD) The induced voltage test with IVPD was conducted as follows: a)

During the whole application of the test voltage, partial discharges were monitored.

b)

The test method and judgment refer to IEC 60076-3: 2000.

c)

Specific provisions are as follows: 1)

For the partial discharge measurement, the voltage was applied according to the following procedure: i)

Switched on at a level not greater than one-third of U2.

ii)

Raised the voltage to 1.1 Um/ 3 and held there for a duration of 5 min.

iii)

Raised the voltage to U2, and held there for duration of 5 min.

iv)

Raised the voltage to U1, if the test voltage frequency was equal to or lower than the doubled rated frequency and the withstand time was 60 s. When the test voltage frequency was greater than double of the rated frequency, the withstand time was:

120 ×

rated frequency ( s ) , but not lower than 15 s. test frequency

v)

Reduced the voltage without interruption to U2 and held there for at least 60 min with partial discharge measured every 5 min.

vi)

Reduced the voltage to 1.1 Um/ 3 and held there for a duration of 5 min.

vii) Reduced the voltage to a value below one-third of U2 before switching off. 2)

3)

4)

When performing the PD test of the main transformer, the test voltages to earth were: i)

U1＝1.5 Um／ 3 .

ii)

U2＝1.3 Um／ 3 .

When performing the PD test of voltage regulating transformer and compensating transformer, the test voltages to earth were: i)

U1＝1.7 Um／ 3 .

ii)

U2＝1.5 Um／ 3 .

The partial discharge values were observed and evaluated according to IEC 60076-3: 2000. i)

Measurements were carried out at the line terminals of all windings. For an autoconnected pair of windings, the higher and lower voltage line terminals were measured simultaneously.

36

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

ii)

The measuring channel from each terminal used was calibrated with repetitive impulse between the terminal and earth, while this calibration is used for the evaluation of readings during the test. The apparent charge measured at a specific terminal of the transformer, with appropriate calibration, referred to the highest steady-state repetitive impulses. Occasional bursts of high partial discharge level were disregarded. Continuous discharges for any length of time occurring at irregular intervals can be accepted, as long as the value is lower than the specified one and there is no steadily increasing tendency. When there is abnormal discharge pulse, the ultrasonic monitoring was added for diagnostic purpose and evaluation.

iii)

Before and after the application of test voltage, the background noise level was recorded on all measuring channels.

iv)

During increase of the test voltage up to level U2 and reduction from U2 down again, possible inception and extinction voltages for partial discharge were noted. Measurement of the apparent charge was taken at 1.1 Um/ 3 .

v)

A reading was taken and noted during the first period at voltage U2, No apparent charge values are specified for this period.

vi)

No values of apparent charge are assigned to the application of U1.

During the entire second period at test voltage U2, the partial discharge level was continuously observed and readings were recorded every 5 min.

A = 5 min, B = 5 min, C = 120 ×

rated frequency (s ) , D = 60 min, E = 5 min. test frequency

Figure A.2—Voltage energizing sequence of partial discharging test NOTE—The IVPD test of main transformer and voltage regulating transformer and compensating transformer is carried out separately before connection. Figure A.2 is the voltage energizing sequence of partial discharging test for the main transformer.

37

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

V is test power source, L is compensating reactor, SB is intermediate transformer

Figure A.3—IVPD test circuit for 1000-kV UHV transformer

5)

The test is successful if i)

No collapse of the test voltage occurs.

ii)

During the long duration test at U2, the continuous level of partial discharges of the main transformer met the following requirements: i)

Does not exceed 100 pC at the high-voltage terminal

ii)

Does not exceed 200 pC at the medium-voltage terminal

iii)

The continuous level of partial discharges of voltage regulating transformers and compensating transformers does not exceed 300 pC at low voltage terminal

iii)

The partial discharge behavior shows no continuously rising tendency at U2. Occasional high bursts of non-sustained nature were disregarded.

iv)

The continuous level of apparent charges does not exceed 100 pC at 1.1 Um/ 3 .

38

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

Annex B (informative) On-site tests for gas-insulated switchgear—Practical examples based on the experiences in China

B.1 Tests for gas-insulated switchgear Tests for gas-insulated switchgear included the following: a)

Visual checks and verifications

b)

Dielectric tests on auxiliary and control circuits

c)

Gas quality (moisture, leakage, and purity)

d)

Measurement of the resistance of the main circuit

e)

Calibration of the SF6 gas density relay and pressure gauge

f)

Circuit breaker tests

g)

Disconnecting and grounding switch tests

h)

Inside component tests

i)

Dielectric tests on the main circuit

B.2 Dielectric test on the main circuit A dielectric test on the main circuit was conducted as follows: a)

The field dielectric test of gas-insulated switchgear filled with SF6 gas to the rated pressure was performed after the installation and all other field commissioning tests had successfully passed. Some components were be isolated in the test due to a higher charge current or limitations of test voltage for these components.

b)

The inlet and outlet of gas-insulated switchgear were disconnected and maintained sufficient insulating distance. The connection of a MOSA to main circuits was done separately. For electromagnetic voltage transformers, consultation with the manufacturer to determine whether to perform the main circuit dielectric test is advised.

c)

During the test, all CTs in gas-insulated switchgear had their secondary winding short-circuited and grounded.

d)

The test was conducted for one unit of gas-insulated switchgear. The unit is a section of the entire gas-insulated switchgear, which encloses the circuit breaker, disconnecting switches, grounding switches, CT, bus, etc. The length of the unit for test may be different than that in the factory and the field, e.g., 20 m and 200 m. For the sections under test, all the disconnecting switches were closed and all the grounding switches were opened. Grounding switches of other sections not under test were closed.

39

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

e)

The insulation resistance of each phase conductor to earth was measured before performing a lowfrequency withstand test at voltage not lower than 2500 V.

f)

A low-frequency ac voltage withstand test was performed as follows: 1)

The test procedure was determined by consultation between the user and the manufacturer based on the equipment condition on-site and design conditions of the gas-insulated switchgear.

2)

The low-frequency series resonance devices and variable-frequency series resonance devices can be used for test power supplies. The test frequencies were from 10 Hz to 300 Hz.

3)

The low-frequency withstand voltage Uf was 80% of the factory test voltage for 1 min.

4)

Consequently, each manufacturer will normally specify an appropriate conditioning procedure. In the Chinese case, for one bay of a 1100-kV gas-insulated switchgear unit, the following voltage energizing sequence was selected by a user based on consultation with the manufacturer: 0→Um/ 3 for 10 min→1.2 Um/ 3 for 5 min. When the conditioning test was finished, the voltage was raised to Uf for a low-frequency withstand voltage test for 1 min. As soon as the voltage returned to 1.1 Um/ 3 after the low-frequency withstand voltage test, the PD test was performed.

NOTE 1— According to IEEE Std C37.122.1™-1993, a conditioning procedure is often used during which low-frequency voltage is applied in gradually increasing levels, since the most common defect results from free-conducting particles, and these are able to move under low frequency excitation. Figure B.1 shows an example of a test procedure which has been used in gas-insulated switchgear. Conditioning tests (for the time duration of “A” and “B”) were performed before a low-frequency withstand voltage test (for the time duration of “C”). It was noted that conditioning is somewhat dependent on the design of gas-insulated switchgear, especially the nature and location of low-field regions for trapping particles as indicated in IEEE Std C37.122.1-1993. NOTE 2— The duration of each step in Figure B.1 is chosen based on factory test experiences. To avoid any possible degrading of the insulation caused by high test voltage, the duration of Step B is reduced.

A=10 min, B=5 min, C=1 min, Um=1100 kV

Figure B.1—Example of a voltage-energizing sequence of the main circuit conditioning test and low-frequency withstanding test

40

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

g)

5)

Specified test voltage was applied between each phase conductor and enclosure. The test was conducted on one phase at a time and other phases were connected to the grounding enclosure.

6)

Test voltage was applied to each component at least once. While formulating the test program, attention was paid to reduce the repetition test time of solid insulation.

7)

If it was noticed that interrupter units of the circuit breakers and/or disconnecting switches had been damaged or dismounted during transportation or installation, the low-frequency withstand voltage test was performed between interrupter units.

8)

If each component of the gas-insulated switchgear had withstood the prescriptive voltage of the test procedure with no disruptive discharge, it was considered that the whole gas-insulated switchgear had successfully passed the test.

9)

If any breakdown happened during the test, a repeat test was carried out. If the equipment can withstand prescriptive test voltage a second time, the former discharge failure can be considered a self-restored discharge, and the low-frequency withstand test was considered passed. If the repeat low-frequency withstand test failed, the damaged compartment was opened and checked. Before re-performing the low-frequency withstand voltage test, necessary restoration measures were adopted.

PD tests were carried out after the low-frequency withstand tests were completed or at the same time as the conditioning test. In order to make PD the tests effective, interference caused by the power source and environment was reduced, and the corona of the high-voltage wire was avoided. The following methods are recommended for PD tests. 1)

Ultra-high frequency (UHF) method. The UHF method enables the detection of internal defects by analyzing electromagnetic waves generated by partial discharges in gas-insulated switchgear. The chosen frequency is usually in the range between 300 MHz and 1.5 GHz. The electromagnetic signal was preferably obtained by sensors for gas-insulated switchgear, e.g., internal sensors.

2)

Acoustic method. The acoustic method can detect the discharge by receiving the ultrasonic signal through acoustic sensors placed on the gas-insulated switchgear enclosure. The measuring frequency is usually in the range between 20 kHz and 150 kHz.

41

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

Annex C (informative) Simulation study for system commissioning

C.1 Background The simulation study for system commissioning is the necessary technical basis for ensuring system commissioning safety. It consists of two parts: the electromagnetic transient analysis and the power flow and stability analysis. The electromagnetic transient analysis focuses on the overvoltage and over-current issues for each commissioning item, such as main electrical equipment switching on/off tests, manual single phase-to-ground tests, etc. Through the simulation, the operation state of the equipment is estimated and the safety measures for the test items are put forward. The power flow and stability analysis focuses on system stability characteristics, control strategies on power flow and system voltage, and also safety measures for system stability. Through the results, the reasonable operation modes of the test power system for each commissioning item can be selected, and the stability of the operating power system can be improved.

C.2 Electromagnetic transient analysis for system commissioning The contents of the electromagnetic transient analysis on test of voltage rising from zero are as follows: 

Calculation of generator self-excitation



Steady-state voltage at the generator terminals, each bus and line side of the ac substation



Steady-state current of transmission lines and relevant equipment



Reactive power of generator and transmission lines



Transient voltage and current under abnormal conditions



Safety precautions recommendation

The contents of the electromagnetic transient analysis on test of current increasing from zero are as follows: 

The maximum current of generator, transformer and transmission lines and other equipment



Steady state voltage of the generator, each bus and line side of ac substation



Transient voltage and current under abnormal conditions



Safety precautions recommendation

The contents of the electromagnetic transient analysis on switching on/off test of no-load UHV power transformers are as follows: 

Switching overvoltage, resonance or harmonic overvoltage, and excitation inrush current



Transient current of surge arrester



System conditions and safety precautions recommendation

42

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

The contents of electromagnetic transient analysis on the switching on/off test of the UHV ac no-load transmission line are as follows: 

Switching overvoltage of neutral point of the ac substation, the transmission lines and the UHV shunt reactor



Steady-state voltage after transmission lines closing



Trigger current of surge arrester



Transient voltage and current under abnormal conditions



System conditions and safety precautions recommendation

The contents of electromagnetic transient analysis on ring closing (interconnection)/ring opening (splitting) of the UHV system test are as follows: 

Ring closing impulse current and switching overvoltage



Ring opening overvoltage



Transient current of surge arrester



Transient voltage and current under abnormal conditions



System conditions and safety precautions recommendation



Voltage amplitude and phase angle difference

The contents of electromagnetic transient analysis on the induced current and induced voltage test of the double-/multi-circuit UHV ac transmission lines on the same tower are as follows: 

Induced voltage of outaged transmission lines with a grounding switch on both sides being switched off



Induced voltage and induced current of outaged transmission lines with a grounding switch on one side being switched off



Induced current of outaged transmission lines with a grounding switch on both sides of the transmission line being switched on



Transient voltage and current under abnormal conditions



System conditions and safety precautions recommendations

The contents of electromagnetic transient analysis on the switching on/off test of tertiary connected capacitors are as follows: 

Current of switching on/off tertiary connected capacitor



Switching overvoltage of tertiary connected capacitor



Transient current of surge arrester



Transient voltage and current under abnormal conditions



System conditions and safety precautions recommendation

43

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

The contents of electromagnetic transient analysis on the switching on/off test of tertiary connected reactors are as follows: 

Current during switching on/off tertiary connected reactors



Switching overvoltage of tertiary connected reactors



Transient current of surge arresters



Transient voltage and current under abnormal conditions



System conditions and safety precautions recommendations

The contents of electromagnetic transient analysis on artificial single phase-to-ground fault tests are as follows: 

Short-circuit current and secondary arc current



Switching overvoltage



Transient current of surge arrester



Transient voltage and current under abnormal conditions



System conditions and safety precautions recommendation

The contents of electromagnetic transient analysis on system dynamic disturbance and normal operation test are as follows: 

Overvoltage and switching overvoltage under abnormal conditions



Transient current of surge arrester



System conditions and safety precautions recommendations

C.3 Power flow and stability analysis contents for commissioning system The contents of power flow and stability analysis on power grid characteristics of the commissioning system are as follows: 

Power flow analysis



Static security analysis



Voltage and reactive power analysis



Transmission capacity of important boundary



System stability analysis and security control strategy analysis

The contents of power flow and stability analysis on tests of voltage rising from zero and current increasing from zero are as follows: 

Test system isolation scheme analysis



Power flow and stability analysis and operational mode arrangement of the main system after the test system is isolated.

44

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above



Analysis of terminal voltage of the generator and voltage of the relevant bus of the isolated system



Analysis of reactive power of the generator and transmission lines of the isolated system



Recommend safety precautions under potential abnormal conditions

The contents of the power flow and stability analysis on the switching on/off test of no-load transformer/transmission line are as follows: 

Analysis of system voltage change before and after switching the on/off no-load transformer/ transmission line



Selection of UHV power transformer taps



Voltage control analysis



Recommend safety precautions under potential abnormal conditions

The contents of the power flow and stability analysis on ring closing (interconnection)/ring opening (splitting) test are as follows: 

Select the locations of splitting/interconnection of UHV system



Voltage control analysis



Impact and disturbance on the operating system by the splitting/interconnection



Recommend safety precautions under potential abnormal conditions

The contents of the power flow and stability analysis on switching on/off test of tertiary connected capacitor/reactor are as follows: 

Analysis of the system voltage change before and after switching on/off the tertiary connected capacitor (reactor)



Voltage control analysis



Recommend safety precautions under potential abnormal conditions

The contents of the power flow and stability analysis on the artificial single phase-to-ground fault test are as follows: 

Operational mode analysis



Short-circuit current analysis



Impact of manual grounding on the system



Recommend safety precautions under potential abnormal conditions

The contents of the power flow and stability analysis on the system dynamic disturbance test are as follows: 

Operational mode analysis



Impact on the operating system by disturbance test

45

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above



Recommend safety precautions under potential abnormal conditions

The contents of the power flow and stability analysis on the normal test are as follows: 

Operation mode analysis



Recommend safety precautions under potential abnormal conditions

46

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

Annex D (informative) Typical measurement items of system commissioning

D.1 Artificial single phase-to-ground fault test The artificial single phase-to-ground fault test is illustrated by the following: 

Figure D.1 is a simplified diagram of the artificial single phase-to-ground fault test.



Figure D.2 is a measurement diagram of the artificial single-phase to ground fault test.



Table D.1 provides instructions for the measurement wiring depicted in Figure D.2.



Figure D.3 is a diagram of the measurement equipment.



Figure D.4 shows the short-circuit current.



Figure D.5 shows the secondary-arc current.



Figure D.6 shows the line recovery voltage and neutral-connected reactor voltage.



Table D.2 lists the field test results of secondary arc current and recovery voltage during a manual single-phase grounding test.

500kV

Transformer

1000kV

1000kV

Shunt reactor

110kV

Neutral reactor

500kV

Grounding point

110kV

Reactor

Figure D.1—Simplified diagram of an artificial single phase-to-ground fault test

47

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

Figure D.2—Measurement diagram of an artificial single phase-to-ground fault test

Table D.1—Instructions for the measurement wiring depicted in Figure D.2 Symbol SCT T1 T2 CT1 CT2 CT3 C1 C2 C3 C4

Description Special CT Bushing of high-voltage shunt reactor Bushing of neutral connected reactor CT of T1 CT of T2 CT of 1000-kV circuit breaker Tap capacitance of T1 Low voltage arm capacitor of voltage divider for T1 Tap capacitance of T2 Low voltage arm capacitor of voltage divider for T2

48

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

Figure D.3—Diagram of the measurement equipment

49

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

Figure D.4—Short-circuit current

Figure D.5—Secondary-arc current

50

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

Figure D.6—Line recovery voltage and neutral-connected reactor voltage

Table D.2—Field test results of secondary arc current and recovery voltage during artificial single phase-to-ground fault test Test line (single circuit line)

Changzhi-Nanyang

Primary short circuit current /kA Peak Rms value value (kA) (kA) 10.4

4.6

Secondary current (peak value) /A

Max recovery voltage (peak value) /kV

Secondary arc extinction time /ms

14.5 (after fault 105 ms)

beating wave 24.5 for trough 145 for crest

118

51

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

D.2 Switching on/off test of on-load UHV transformers The switching on/off test of on-load UHV transformers is illustrated by the following: Figure D.7 is a simplified diagram of the switching on/off test of no-load UHV power transformers. Table D.3 provides measuring connection instructions related to Figure D.7

Figure D.7—Simplified diagram of switching on/off test of no-load UHV power transformer

Table D.3—Measuring connection instructions related to Figure D.7 Symbol T1 T2 CT1 C1 C2 C3 C4 CTr

Description 1000-kV circuit breaker 1000-kV bushing of UHV power transformer 500-kV bushing of UHV power transformer CT of T1 Cap capacitance of T1 Low voltage arm capacitor of voltage divider for T1 Cap capacitance of T2 Low voltage arm capacitor of voltage divider for T2 Current clamp

52

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

D.3 Switching on/off test of tertiary connected capacitors The switching on/off test of tertiary connected capacitors is illustrated by the following: Figure D.8 is a simplified diagram of the switching on/off test of tertiary connected reactors. Table D.4 provides measuring connection instructions related to Figure D.8.

Figure D.8—Simplified diagram of switching on/off test of tertiary connected reactors

Table D.4—Measuring connection instructions related to Figure D.8 Symbol T3 C5 C6 CT D1, D2

Description 110-kV circuit breaker 110-kV bushing of UHV power transformer Cap capacitance of T3 Low voltage arm capacitor of voltage divider for T3 CT of T3 RC voltage divider

53

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

D.4 Audible-noise measurement of substation and transmission lines Figure D.9 provides locations of substation and transmission line audible-noise measurement points.

A

House2 2

3

N W

1

E S

13

4

12

5

Substation

D

11

B 6

Hospital 10

7 House1

8

9

school

C

1-13: measurement points around the substation A-D:Audible noise measurement points at audible noise control boundary

Figure D.9—Locations of measurement points

54

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

Annex E (informative) Bibliography Bibliographical references are resources that provide additional or helpful material but do not need to be understood or used to implement this standard. Reference to these resources is made for informational use only. [B1] CIGRE WG B3.29, Technical Brochure No. 562, 2013, Field tests for UHV substations. 7 [B2] CIGRE WG B3.22 Technical Brochure No. 400, 2009, Technical requirements for substations exceeding 800 kV. [B3] CIGRE WG C4.302, Technical Brochure, No. 360, 2008, Insulation coordination related to internal insulation of gas-insulated systems with SF6 and N2/SF6 gas mixtures under ac condition. [B4] IEC 60044-1:2003, Instrument transformers—Part 1: Current transformers. 8 [B5] IEC 60076-6:2007, Power transformers—Part 6: Reactors. [B6] IEC 60076-10:2002, Power transformers—Part 10: Determination of sound levels. [B7] IEC 60099-4:2004, Surge arresters—Part 4: Metal-oxide surge arresters without gaps for a.c. systems. [B8] IEC 60129:2000, Alternating current disconnectors and earthing switches. [B9] IEC 60156:1995, Insulating liquids—Determination of the breakdown voltage at power frequency— Test Method. [B10] IEC 60247:2004, Insulating liquids—Measurement of relative permittivity, dielectric dissipation factor (tanδ) and d.c. resistivity. [B11] IEC 60270:2000, High-voltage test techniques—Partial discharge measurements. [B12] IEC 60296:2003, Fluids for electrotechnical applications—Unused mineral insulation oils for transformer and switchgear. [B13] IEC 60376:2005, Specification of technical grade sulfur hexafluoride (SF6) for use in electrical equipment. [B14] IEC 60567:2011, Oil-filled electrical equipment—Sampling of gases and of oil for analysis of free and dissolved gases—Guidance. [B15] IEC 60815-1:2008, Selection and dimensioning of high-voltage insulators intended for use in polluted conditions—Part 1: Definitions, information and general principles. [B16] IEC 60815-2:2008, Selection and dimensioning of high-voltage insulators intended for use in polluted conditions—Part 2: Ceramic and glass insulators for a.c. systems. [B17] IEC 60815-3:2008, Selection and dimensioning of high-voltage insulators intended for use in polluted conditions—Part 3: Polymer insulators for a.c. systems. [B18] IEC 61462:2007, Composite hollow insulators—Pressurized and unpressurized insulators for use in electrical equipment with rated voltage greater than 1000 V—Definitions, test methods, acceptance criteria & design recommendations. 7

CIGRE publications are available at: http://www.e-cigre.org/. IEC publications are available from the Sales Department of the International Electrotechnical Commission, 3 rue de Varembé, PO Box 131, CH-1211, Geneva 20, Switzerland (http://www.iec.ch/). IEC publications are also available in the United States from the Sales Department, American National Standards Institute, 25 West 43rd Street, 4th Floor, New York, NY 10036, USA (http://www.ansi.org). 8

55

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

IEEE Std 1861-2014 IEEE Guide for On-Site Acceptance Tests of Electrical Equipment and System Commissioning of 1000 kV AC and Above

[B19] IEC 62271-100:2008, High-voltage switchgear and controlgear—Part 100: Alternating-current circuit breakers. [B20] IEEE Std 1312™-1993, IEEE Standard Preferred Voltage Ratings for Alternating-Current Electrical Systems and Equipment Operating at Voltages Above 230 kV Nominal. [B21] IEEE Std C37.100™-1992, IEEE Standard Definitions for Power Switchgear. [B22] IEEE Std C37.122.1™-1993, IEEE Guide for Gas-Insulated Substations. [B23] IEEE Std C57.12.10™-2010, IEEE Standard Requirements for Liquid-Immersed Power Transformers. [B24] IEEE Std C57.12.70™-2011, IEEE Standard for Standard Terminal Markings and Connections for Distribution and Power Transformers. [B25] IEEE Std C57.91™-2011, IEEE Guide for Loading Mineral-Oil-Immersed Transformers and StepVoltage Regulators. [B26] IEEE Std C57.98™-2011, IEEE Guide for Transformer Impulse Tests. [B27] IEEE Std C57.104™-2008, IEEE Guide for the Interpretation of Gases Generated in Oil-Immersed Transformers. [B28] IEEE Std C57.106™-2006, IEEE Guide for Acceptance and Maintenance of Insulating Oil in Equipment. [B29] Nitta, T., Y. Shibuya, Y. Fujiwara, Y. Arahata, H. Takahashi and H. Kuwahara, “Factors controlling surface flashover in SF6 gas-insulated systems”, IEEE Tranactions on Power Apparatus and Systems, vol. PAS-97, no. 3, pp. 959–968, May 1978. [B30] Uehara, K., T. Kobayashi, G. Li, J. Fan, B. Li, S. K. Agrawal, J. H. Kim and C. Oh, “On-site test at UHV substation”, CIGRE 2012, Common Session, B3-213 (2012). 9

9

Available at: http://www.cigre.org/content/download/16997/680451/.../B3_213_2012.pdf

56

Copyright © 2014 IEEE. All rights reserved.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.

I EEE s t andar ds . i eee. or g Phone:+17329810060 Fax:+17325621571 ©I EEE Authorized licensed use limited to: IEEE Xplore. Downloaded on December 11,2014 at 18:40:43 UTC from IEEE Xplore. Restrictions apply.