Transmission-line-commissioning-publication_no.292.pdf

Central Board of Irrigation and Power

MANUAL COMMISSIONING PROCEDURE FOR TRANSMISSION LINES

PUBLICATION NO. 292

Editors

G.N. MATHUR KULDIP SINGH

ISO 9001: 2000

CENTRAL BOARD OF IRRIGATION AND POWER

2006 ISBN: 81-7336-299-8

"Reproduction of articles in publication in any form is permissible subject to proper acknowledgement and intimation to the publishers. The publishers have taken utmost care to avoid errors in the-publication. However, the publishers are in no way responsible for the authenticity of data or information given by the contributors."

List of the experts Late Shri P.M. Ahluwalia Former Member Central Elecricity Authority, New Delhi Dr. V.N. Rikh Former Chairman UP State Electricity Board, Lucknow Shri V.D. Anand Former Chief Engineer Central Electricity Authority New Delhi Shri M.L. Sachdeva Fomler Chief Engineer Central Electricity Authority, New Delhi Dr.S.Mukhopadhyay Chief Engineer Central Electricity Authority New Delhi Shri Umesh Chandra Executive Director Power Grid Corporation of India Ltd. Gurgaon Shri D. Chowdhury General Manager Power Grid Corporation of India Ltd. Gurgaon Shri S.M. Takalkar Superientending Engineer (Trans) Gujarat Electricity Board, Vadodara Shri S.K. Gupta Deputy General Mannger (OS) Power Grid Corporation of India Ltd. Lucknow Shri Vijay Pal Deputy Director Central Electricity Authority New Delhi Shri Praveen Vasishth Deputy Director (TCD) Central Electricity Authority New Delhi

Shri Devender Sharma Director (TCD) Central Electricity Authority New Delhi Shri M. Krishankumar General Manager Power Grid Corporation of India Limited Gurgaon Shri K. Mohan Das Chief Design Engineer National Thermal Power Corporation Ltd. Noida Shri L. Khubchandani 0-202, Vasant Sarita, Near Gokul Nagari I Opp. Thakur Polytechnic, Off Western Express Highway Kandivili East, Mumbai Shri L.N. Aggarwal Additional Vice President Reliance Energy Limited Noida Shri Neeraj Kumar Deputy Director (TCD) Central Electricity Authority New Delhi Shri RSen Chief Design Engineer(Engg. & TL) Power Grid Corporation of India Limited Gurgaon Shri G.D. Rathod General Manager (Engg.) Trans Rail Structures Gammon House, Vir Savarkar Marg, Prabhadevi, Mumbai Shri E.V. Rao Chief Manager (Engg.) KEC International Limited , B-190, M IDC Industrial Area BUTIBORI- 441 108 Nagpur Distt. Maharashtra. Dr. S.K. Agarwal General Manager Power Grid Corporation of India Limited Gurgaon

'i:''lIT'I (
Tel ephone (0) : 011-26102583 ~ Te!efax: 01 1-26109212

31U!e:\
1T<8'

~ ~ ~

~~~ ~~ CHAIRPERSON & EX-OFFICIO SECRETARY TO THE GOVERNMENT OF INDIA

CENTRAL ELECTRICITY AUTHORITY SEWA SHAWAN, R. K. PURAM

RAKESH NATH

~ ~ - 110066 NEW DELHI· 11 0066

FOREWORD

The Government of India has an ambitious mission of "POWER FOR ALL BY 2012". This mission would require that our installed generation capacity should be about 2,07,000 MW by 2012 from the present level of 1,23,543 MW. It would essentially require commensurate expansion of the regional transmission network and inter-regional transmission capacity not only for transmitting power from this planned additional generation capacity but also for having adequate margins for open access for a vibrant power market. Augmentation in inter-regional capacity is required because resources are unevenly distributed in the country and power is to be hauled from power surplus regions to deficit regions. While the predominant technolugy for electriCity transmission and distribution has been Alternating Current (AC) technology, High Voltage Direct Current (HVDC) technology has also been used for interconnection of regional grids across the country arid for bulk transmission of power over long distances. The AC transmission network of our country for 110 kV level & above stands at 2,65,350 ckm where as DC transmission network for ± 500 kV stands at 3140 ckm by end of ninth Plan (1997-2002). The country's transmission perspective plan for tenth and eleventh plan focuses on the creation of a National Grid in a phased manner by adding over 1,56,860 ckm of AC Transmission Network and 8140 ckm of DC transmission network (± 500/600 kV) during tenth Plan (2002-07) and eleventh Plan (2007-12). Such an integrated grid shall evacuate about 1,00,000 MW additional generating capacity planned for tenth and eleventh Plan. The existing inter-regional power transfer capacity of 9,500 MW is to be further enhanced to 37, 150 MW by 2012 through creation of "Transmission Super Highways". For successful commissioning of transmission line, it is very important that commissioning procedures are religiously followed to avoid any impediments. In this context, the Manual of Commissioning Procedure for Transmission Line, brought out by CBIP, has all the requisite guidelines on various aspects, such as, safety procedures, statutory requirements, protection system, switching procedures, testing, energization/de-energization, etc. This document prepared by CBIP through ~~~ii~~ Save Energy for Benefit of Self and Nation

the Expert Group headed by Shri P. M. Ahluwalia, Ex-Member, CEA will definitely help the utilities in speedy construction and commissioning of transmission line . I sincerely appreciate the in time efforts of Central Board of Irrigation and Power for bringing out such document and congratulate them for their initiative. I hope that this document would serve as a useful guide for the power utility engineers in the country.

( RAKESH NATH )

Preface One of the prime activities of Central Board of Irrigation and Power is to bring out technical Publications for the reference and information of practicing engineers. So far CBIP has prepared 147 manuals, Guidelines and Technical reports covering all areas of Power Sector and is in the process of preparing / revising 10 manuals (4 pertaining to Transmission). These not only provide guidelines to the utility engineers but are also being used as reference books for the academic institutions. Realizing the requirement and demand the Central Board of Irrigation and Power, decided to bring out publication titled "Guidelines for Commissioning Procedures for Transmission lines". This publication is the out come of the hard work by the authors and valuable time spent by the expert group headed by Shri P.M. Ahluwalia, Ex-Member, CEA in finalizing the document. The Central Board of Irrigation and Power is extremely grateful to the authors of this document particularly Dr. S.K. Agarwal, Shri S.K. Gupta, and Shri Rajeev Kumar all from Power Grid Corporation of India Limited . Contribution of late Shri A.K. Kapur, Ex Executive Director, POWERGRID in preparation of this document deserves separate and special mention. Special thanks are also due to Shri P.M. Ahluwalia, Chairman of Panel of Experts and other members of the panel for the tremendous input and direction given in finalizing the manual.

r am sure that the publication will be of immense use and great reference value to the Manager' ent and Practicing engineers of Power Utilities and Transmission lines Companies, Researchers, Testing Stations, Faculty members and student of Engineering Institutes in India.

G.N. Mathur Secretary Central BoardofIrrigation and Power

CONTENTS

Page No. Forword Preface l.0

INTRODUCTION

2.0

OVERALL PROCEDURE

3.0

SAFETY PROCEDURES

4.0

v VI]

' 2

INSPECTION

2

4.1 Right of Way / Way Leave / Electrical Clearance 4.2 Foundation 4.3 Tower and Tower Accessories 4.4 Insulators 4.5 Conductors and Earth Wires 4.6 Accessories for Conductor and Earthwire 4.7 Aviation Warning Obstruction Signals (Lights/ Globules/ Painting)

2 5 5 6 7 7 8 8

5.0

STATUTORY REQUIREMENT

6.0

HANDING OVER

7.0

PROTECTIVE/ METERING SYSTEM

8.0

DISPA TCH PROCEDURES

9.0

SWITCHING PROCEDURES

10.0 TESTING AND MEASUREMENT PROCEDURES 10.1 Earth Resistance Measurement 10.2 Testing 10.3 Phase Sequence 1l.0 ENERGIZA nON 12.0

DE-ENERGIZA TION

13.0

OBSERVATION

14.0

PASSING CRITERIA

15.0

DOCUMENTA TION

8 9 9 9 10 10 11 12 13 13 13 13 14

Page No. ANNEXURE - I

IS

Indian Electricity Rules, 1956 Chapter VII Electric Supply Lines, Systems and Apparatus for High and Extra-High Voltages ANNEXURE-II

20

Sample Check List for Transmission Line ANNEXURE-III

25

ANNEXURE-IV

26

ANNEXURE-V

28

1.0

INTRODUCTION

This document includes over all procedure, safety rules, statutory requirements and documentation of test results for commissioning procedures for transmission lines . The commissioning of the transmission line is to be carried out alongwith the substations at both the ends. The detailed inspection and handing over documents are required to be checked for the entire length of transmission line before energization. The detailed inspection/test procedures for each activity have been elaborated in separate section of this document. The document including transmission line contains the following : • Overall procedures • Safety procedures • Inspection • Statutory requirements • Handing over • Protective system • Dispatch procedures • Switching procedure • Testing • Energization • De-energization • Observations • Passing criteria • Documentation

2.0

OVERALL PROCEDURE

First, it is to be ascertained that the transmission line to be energized is ready for operation and has been properly handed over (released) in writing. This will include all safety aspects, electrical inspector clearance, PTCC clearance, statutory clearance, and final inspection, if any. Instructions for the work and supervision are given by the test leader (line in-charge). However, regular operators will execute all switching and operational activities. Line charging instructions received from engineering/ design deptt. of the utility are clearly understood by the line in charge and doubts, if any, are to be got clarified prior to the energization of the line. Once the line is handed over for charging, any further work shall be pennitted only with a valid work penn it. When the whole system including transmission line has been energized, it will be kept in this state for 8 hours or more for ' soaking' with continuous inspection and monitoring. However, ensure that the recommendations of engineering/design department of concerned utility are implemented before commissioning.

2

3.0

Publication No. 292

SAFETY PROCEDURES

Energization implies an abrupt and serious change of the working conditions in the line. In order to avoid serious accidents, thorough information must be imparted to all personnel involved in the construction of transmission line. In-charge of the transmission line (Divisional head) must ensure that due pUblicity has been made to the public in all the villagesl areas along the line route cautioning them against climbing the towers etc. and that the line is proposed to be charged on notified date. It is also to be con finned that all the Agencies involved in the construction activities shall not carry out any job on the said line without a valid work permit. It shall be ensured before charging that all men, material,tools and plants and any temporary earthing on any part of the entire length ofline are removed. It must be ensured that any power supplyl low voltage charging used as anti-theft measure must be disconnected and isolated to avoid accidental connection. All equipment tests and pre-commissioning tests must have been completed, reconnected (in case cables were isolated for testing purpose) and documented as per prescribed format for Pre-Commissioning Procedures of SIS Bay Equipment. The system must be formally declared ready for energization and handed over for operation in writing. 4.0

INSPECTION

Before the line is scheduled to be handed over for the pre-commissioning/ energization the same shall be inspected by representatives of the utility and erection . agency. Such inspection shall include : (i) Right of way I way leave I electrical clearance (ii) Foundation (iii) Tower and tower accessories (iv) Hardware fittings (v) Insulators . (vi) Conductors and earth wire (vii) . Accessories for conductor and earth wire (viii) Aviation warning signals (lights/ globules/ painting) 4.1

Right of Way I Way Leave I Electrical Clearance

4.1.1

Right o/way/ way leave clearance

Width of maximum right of way permitted as per forest conservation act ' 1980 and its subsequent amendment dated 25 th October 1992, are as per Table 1. Researches are being carried out for fUliher optimizing the Right of Way. Guidelines of fores t! environmental rules shall be followed to avoid excessive tree cutting, i.e., all the trees should be cht from root level in the 3 ill corridor below each

3

Manual on Commissioning Procedure/or Transmission Lines

line conductor/ earth wires. In the balance corridor, trees branches are only to be lopped to attain the specified clearance as per Table I . Table 1 Guidelines for Right of Way as per forest conservation act 1980 and subsequent amendment dated 25 th October 1992 500 HVDe 52

4.1.2

Electrical clearance

4.1.2.1 Electrical clearance while power lines crossing each other

In case of power line crossings, minimum clearance between lowest conductor of line and ground wire/ top conductor of the other line shall be as per Table 2. Table 2 Minimum clearances in mm between lines when crossing each other SL No.

66

132

220

400

500 HVDC

765

Line voltage (kV)

I

66

2440

3050

4580

5490

6790

7940

2.

132

3050

3050

4580

5490

6790

7940

3.

220

4580

4580

4580

5490

6790

7940

4.

400

5490

5490

5490

5490

6790

7940

5.

500 HVDC

6790

6790

6790

6790

6790

7940

6.

765

7940

7940

7940

7940

7940

7940

Jumpers in the tension tower are properly bolted with the tension clamp and form a parabolic shape in order to achieve adequate clearance from the structure. 4.1.2.2 Ground clearance

Normally at the time of construction, adequate clearance is provided between lowest conductor and ground, but due to delay in charging/ commissioning there are chances of dumping! heaping soil, earth and concrete etc. or stacking bricks etc., that may cause reduction in ground clearance. In such cases the stored materials shall be removed. Temporary or permanent structures which do not fulfill the requirement of rule no. SO oflE rules should be removed prior to charging of transmission line. The various clearances are given in Table 3 are mandatory. However all the clearances indicated as per approved drawings by engg./ design deptt. of the utility, are to be referred.

Publication No. 292

4

Ground clearance of lowest conductors at critical points shall be checked at prevalent temperature in the field by any of the prevalent method and the values of ground clearance at these critical points shall be recorded in the prescribed format. In case of hilly terrain and for building clearance, the side clearance from conductors and jumpers at critical points shall also be checked and recorded for all phases of conductor/ earth wire towards hill/ building side. Table 3 Permissible minimum ground clearance for different voltage level

4.1.2.3 Clearance/or telephone line crossings

The minimum clearances between the conductors of the power line and telecommunication lines are specified in Table 4. Table 4 Minimum cl earance between conductor of power line and telecommunication line

4.1.2.4 Electrical clearance/rom railway tracks

As per regulations for power line crossings of railway tracks- 1987 and its subsequent amendment dated 26 th August 1988, the minimum clearance between railway track and the bottom most conductor of power line crossing the railway track shall be as per Table 5. Table 5 Ciearances as per regulation for power line crossing railway track-I 987 Line voltage/ clearance (kV) Above track (mm) Over crane (mm)

66 14100 2000

132 14600 2500

220 15400 3500 .

400 17900 6000

500 HVDC 19300 7250

765 23400 11500

4.1.2.5 Clearance between conductor and ground wire at mid span

The vertical clearances between conductors and earth wire shall be checked randomly say in anyone span of all ,sections and lO% sectiom of hilly areas from single line diagram of the towers. These clearances are specified in Table 6. Table 6 Clearance between conductor and ground wire "at mid span" as per clause no . 4.10.2 of CBlP Transmission Line Manual Line voltage (kV) Minimum mid span clearance (mm)

66

132

220

3000

6100

8500

400 9000

500 HVDC 8500

765 12400

4.1.2.6 Minimum clearance above rivers/ lakes

In case of accessible frozen rivers/ lakes, the minimum clearance above frozen rivers/ lakes should be equal to the minimum ground clearance given in Table 3. The minimum clearance of power conductor over the highest flood level in case of rivers shall be as given in Table 7.

5

Manual on Commissioning ProcedureJor Transmission Lihelf

Table 7 Min clearance between lowest conductor and highest flood level of river Line voltage (kY) Minimum clearance above river or lake or water stretches Non navigable river (from HFL) in mm Minimum clearance above navigable river (from HFL) in mm

4.2

66 3650

132 4300

220 5100

400 6400

765 13200

500 HYDe 10650

19000

19220

20100

21900

25900

21900

Foundation

There shall not be any damage/ uneven settlement of foundations . For this, tolerances in levels of all four stubs should not exceed the criteria provided in the Annexure - C of IS -5613 (Part -3/Section 2): 1989. It is to be ensured that back filling of foundation is properly done as per the requirement of specification. Extra surface earth after foundation back filling shall be removed from legs of the tower as per provision of the specification. 4.3

Tower and Tower Accessories

4.3.1

Normal tower

After completion of a transmission line, all the towers shall be thoroughly checked before charging the line. Special attention shall be given to the following points: •

• •

•

•

It is to be ensured that no members are bent, deformed or rusted in towers and if so, the same shall be replaced. If any members is found missing, a new member shall be fixed as per erection drawing of towers . Nuts shall be sufficiently tightened. Minimum 2 to 3 threads shall provide outside the nut. All bolts shall have their nuts facing .outside of the tower for horizontal connection and downwards for vertical connections. Bolts shall be punched as per specification and nuts shall be properly tack welded. It shall be ensured that the cintular length of each welding shall be at least 10 mm . Proper zinc rich paint (90% zinc content) shall be applied on welded portion. It shall also be ensured that all blank holes provided on tower members are filled with nuts and bolts of correct size except holes for step bolts below ACD .

4.3.2

Special towers

In addition to the above checks for towers, ladders and platforms provided in special towers shall be properly tightened and no foreign material shall be left out on such platforms.

4.3.3

Earthing of towers

It shall be ensured that proper earthing of tower has been done and properly fixed to the stubs. The earthing strip shall neither be damaged nor broken.

Publica/ion No. 292

6

In case of counter poise earthing, it is to be ensured that earth wire is sufficiently buried in the ground and not dragged out. The length of counterpoise is normally 15/30 m as per technical specification. Before charging of the line, ensure that earth resistance of each tower is below 10 ohms. If the value (before stringing) has been recorded higher than 10 ohm , additional counterpoise type earthing shall be provided. Earthing of special towers shall be verified as per approved drawings applicable for special towers/ special foundation. (in case of anchor foundation bolt/anchor plate welded with last leg of special tower) 4.3.4

Tower accessories

All the danger plates , number plates, circuit plates, and phase plates shall be in position as per the specification and properly tightened . All phase plates shall be fixed in correct phase sequence. Special care may be taken at transposition towers for indicating the correct phase sequence. It shall be ensured that the anti-climbing device (ACD) is provided at the suitable height of tower. In case of barbed wire type ACD , barbed wire shall be tightly fixed. In case of spike type ACD, all spikes shall be properly fixed and oriented towards outer face of tower. It shall be ensured that the step bolts (for normal towers) are provided up to the peak of tower. Any missing step bolts shall be replaced. Fixing of birds guards as per specification shall be ensured.

4.3.5

Hardware/ittings

Tightening of all bolts and nuts are to be checked Lip to specified torque. Check the fixing of all security clips (W/ R type clips). Surface condition of corona contTol rings, distancel alignment between tower side arcing horn (wherever applicable) and line side arcing hom/ corona control ring to be checked as per approved drawings. To restrict the swing of jumpers, the provision of pilot strings in case of tension towers shall be verified from the approved drawings .

4.4

Insulators

All the damaged/broken insulator discs shall be replaced. Unusual deflection in suspension strings if observed shall be rectified. The insulators shall preferably be cleaned before charging. Ensure where specified that number of insulators discs per string is lesser by one number as compared to number of discs in normal string (up to 220 kV) at approach spans to the telminal ends (approx last 1.5 km). IR value of individual disc of at least 5% insulators at random shall be checked by 51 10 kV Megger and it shall not be less than the specified value.

(l.,loJ1l1ol on COmnllSJ:lOtllng j.Jl'ocedlll'ejOr

4.5

Conductors and Earth Wires

4.5.1

Conductor

n 'ansmission Lines

7

Surface of the conductors shall be free from scratches/rubs . Ensure that conductor strands are not cut and opened up. Wherever strands are found cut/damaged/scratched, they must be repaired with repair sleeves/repair protective rods th in case the number of damaged strands are within specified limits (normally up to 1/6 nos. of strands in the outer layer for lines up to 220 kV voltage level and maximum 2 strands in case of 400 kY and higher voltage level).

4.5.2

Earth wire

Ensure that no strands of earth wire have cuts. No repair sleeve shall be provided on Earth wire.

4:6

Accessories for Conductor and Earthwire

4.6.1

Joints

All joints on conductor/ earth wires shall be away from the tower at a distance of at least 30 m or as provided in the Technical Specification (TS). Ensure that not more than one joint in a conductor is provided in one span. Ensure that no mid span joint is provided in major crossings such as main roads, railway tracks and major rivers etc. or as per the provisions of technical specification. ensure that all mid span joints on conductors / ealth wire and repair sleeves of compression type are free from sharp edges, rust · and dust. Wherever grease is specified, the same shall be applied in the joints.

4.6.2

Spacers, vibration dampers and copper bonds

Placement and number of spacers/ spacer-dampers on the bundle conductors on each phase shall be verified as per spacer/ spacer damper placement chart. Damaged! missing spacers/ spacer-dampers shill be replaced and loose/displaced spacers/ spacerdampers shall be tightened/ relocated. Spacing of vibration dampers from the tower and spacing between damper to damper shall be verified as per the damper placement chart. All loose/ displaced YD shall be properly tightened/ relocated and missing YDs shall be provided . It is to be ensured that no copper bond is loose/ missing.

4.6.3

Jumpers

Randomly check electrical clearance of jumpers to tower body as per design. In case, any jumper bolts (conductor/ earth wire) is found loose, it shall be tightened to specified torque.

Publication No. 292

8

4.6.4

Foreign material

Ensure that all foreign materials like dead bird, fallen tree branches; bird nests, etc., on conductors, ealih wires, jumper, insulator string, cross-arms are removed .

4.6.5

Otllers

Ensure that all temporary/ local earthing, guys , T & P (Tools and Plants), foreign material and other loose material, which were used during stringing/ tower erection. have been removed. ff, there is any change in ground profile before commissioning of line from the approved profile, the extra earth/ obstruction/ temporary sheds/ any other construction shall be removed. 4.7

Aviation Warning Obstruction Signals (Lights/ Globules/ Painting)

It shall be ensured that following measures have been taken in the line/towers falling within obstruction zone of civil aviation and defence establishments as per Amendment No. I, July 1994 to IS 5613 (Part 3/ Sec 1):1989 and the specification of the utility. 4.7.]

Day markers

Painting of full! top portion of towers with international orange and white paints. globules on earth wires have been provided. 4.7.2

Nig/tt markers

Ensure that proper aviation lights at the peak level! at specified heights of towers have been provided along with solar panels/ battery banks/ control cubicles and other accessories as per specification . The functioning of lights is to be checked/ verified by simulation. ' ;'0"

5.0

STATUTORY REQUIREMENT

The concerned authorities shall be informed before commissioning the lines and their approval shall be obtained in accordance with Indian Electricity Act, Indian Electricity Rules and Electricity Supply Act as amended from time to time. Before charging ofthe line, PTCC approval from P&T Department shall be obtained . Relevant clause of IE rules, 1956 are reproduced at Annexure-I. The same may be referred and complied with by the engineer concerned prior to taking up the precommissioning activities of transmission lines.

6.0

HANDING OVER

The transmission line shall be inspected prior to energization and a formal handing over document to be jointly signed by the representative of supplier (if available), erection agency and the utility. However, all contractual taking over has to be resolved

Manual on Commissioning Procedure f or Transmission Lilies

9

separately as per the terms and conditions of the contract. The handing over shall be limited to the completion of erection and ready for energization . A sample format enclosed at Annexure-II. Any outstanding points or remaining activities are to be listed jointly by the utility and erection agency representatives. A sample format is enclosed at Annexure-Ill. These documents are also to be retained at line office with a copy to Regional office. The remaining activities outstanding points are classified in the following category. Details of the sections: (a) (b) (c) (d)

List of outstanding activities remaining in any part of the line A list of temporary arrangements introduced. Check list of records properly documented, completed and signed (sample format at Annexure-II) Original tracing of profile, route alignment, tower design, structural drawings, bill of materials , shop drawings, stringing charts (initial and final as applicable) etc. of all towers/ line submitted t9 the utility.

After resolving the above mentioned outstanding activities or with only minor issues which do not influence on charging of line, handing over of the transmission line shall be accepted by the commissioning team. Handing over of transmission line for energization with or without remaining activities (sample format at Annexure-IV) shall" be made by the line in-charge to the commissioning in charge in writing. Shortcomings noticed during the inspection, "List of outstanding activities" shall be recorded as per the sample format (Annexure-Ill) to be used and a copy of the format is to be given to the responsible parties like supplier agency (s) and erection agency etc. for corrective action to be taken on a time bound schedule.

7.0

PROTECTIVE/ METERING SYSTEM

Before energization, it must be ascertained that all protective and metering systems (necessaty to charging of the line) provided on the transmission line feeder are operative.

8.0

DISPATCH PROCEDURES

All operational activities (switching etc.) must be coord.inated and communicated with the system dispatcher of the utility. In this respect, general procedures already established by the utility will be followed.

9.0

SWITCHING PROCEDURES

All operational activities (switching, etc.) must be coordinated and communicated with the system dispatcher of the utility as per the established procedure. For each activity, the instructions to the operators and the communications to the system dispatchers must be in writing or by confirmed telephone messages. Step by step switching procedures should be properly documented and understood by every-

Publication No. 292

10

body involved in the switching operation prior to the energization. Any clarification required in the procedures must be resolved. The format established by the utility for switching orders and operational data logging shall be followed. Complete information should be recorded and preserved for detailed investigation , if required in future.

iO.O

TESTING AND MEASUREMENT PROCEDURES

10.]

Earth Resistance Measurement

Earth tester is used for measuring (a) Soil resistivity. (b) Earth resistance Prior to the testing of soil resistivity and earth resistance the operation manual of the testing instrument avai lable at site may be referred to be decided . A typical earth tester has 4 terminals. Cl, PI, C2, P2 and 4 similar electrodes are driven in the ground at equal distances and connected to the instruments in the order of C 1, P I and P2, C2 . Then the handle is rotated in case of manual operated megger or button is pressed in case of battery/motor operated and the reading of the resistance is read on the megger scale. If R is the resistance measured then the, Specific resistivity = 2n a R Where, a is the distance between the electrode in metres, R is the resistance in ohms measured on the megger Specific resistivity will be in ohm-meters [n order to measure earth resistance of electrode, it could be connected to PI and CI (shorted) and the value ofR could be read in the scale with the rotation of the handle in case of manually operated instrument or by pressing the button in case of battery/ motor operated instrument. This will give the earth resistance as done in 3 spike method. The value of eaJth resistance of the electrode in the pit should be below 10 ohm. If the value exceeds 10 ohm, additional pipe/counterpoise type earthing shall be provided.

PI

0-

~

l

I

/

CI

I

Potential Electrode /

0

~/

/ /

/

. .,

Test connections for a four terminal megger

Potential Electrode

j

C2'j

~

/

l

P2

/

/

a

/

/

/

/

Manual on Commissioning Procedure for Transmission Lines

10.2

II

Testing

Before commissioning ofthe lines, following tests may be carried out.

10.2.1

Insulation resistance test

This test may be carried out with the help of a 5 or 10 kV megger preferably power driven to ascertain the insulation condition of the line. In case 5 kV megger is used for insulation resistance measurement it shall be ensured that the induced voltage (CVT reading) is less than the instrument withstanding capacity otherwise it is likely that the instrument may be damaged. This test is to be carried out first prior to the continuity test.

10.2.1.1 Measurement a/insulation resistance One of the most common devices used for testing electrical insulation is the megger or insulation tester. The DC test voltage is generated by a permanent magnet generator. This generator is turned either by hand or by an electric motor. In either case a slip clutch maintains the generator speed at a constant value so long as the slipping speed is exceeded. A constant voltage is important when the insulation under test has a high capacitance. The generator output ratings are 500, 1,000,2500,5000 and 10000 volts. Many meggers have a "guard" terminal as well as "line" and "earth". The guard terminal is useful if one wish to exclude part of the insulation under test from the measurement. This is possible since current flowing to the generator via the guard circuit does not pass through the deflecting coil. Another use of the guard circuit is to shield the "line" lead between the megger and the apparatus under test. This prevents leakage to ground from the "line" lead which would invalidate the megger reading. Insulation resistaJ;1ce is the ratio V DC/ IDC . VDC is applied across two conductors separately by the insulation under test. IDC is the current flowing through! over the insulation. For a healthy and clean insulation, the megger reading is in mega-ohms to infmity. For dirty, defective, moist . insulation, the megger shows a very low insulation resistance value. Megger test gives clear indication about the health, cleanliness and dryness of the line/ equipment insulation. 5 kV megger or 10 kV megger may be used for the transmission line keeping all safety requirements, permit to work, clearance from statutory bodies and other conditions prevailing at the sub-station where charging of the line is being cocoordinated.

10.2.2 Conductor continuity test 10.2.2.1 The objective of this test is to verify that each conductor of the overhead line properly connected electrically (the value of electrical resistance of line does not vary abnormally from that of a continuous conductor of the same size and length). The

Publication No. 292

12

electrical resistance of the conductor shall be measured with a Whetstone bridge or other suitable instrument, if available taking the safety aspects of equipment as well as testing engineer. A simple method of continuity test is illustrated below. Once the insulation test is completed and the results confirms no short circuit carry the following: Sending end

Receiving end

Results (OHMS)

Close R- Ph GS

Megger R-Ph

Zero/ Low

Open Y- Ph GS

MeggerY-Ph

High

Open B-Ph GS

Megger B-Ph

High

Open R- Ph GS

MeggerR-Ph

High

Close Y- Ph GS

Megger V-Ph

Zero/ Low

Open B- Ph GS

MeggerB-Ph

High

Open R- Ph GS

MeggerR-Ph

High

Open Y- Ph GS

MeggerY-Ph

High

Close B- Ph GS

Megger B-Ph

Zero/ Low

(All GS open condition) GS means Ground Switch If the above test results are OK it confirms the continuity of the line.

10.2.2.2 The continuity test of the line with proper phase indication or phase marking can be checked by continuity test as described below: Sending end

Receiving end megger between R phase & Y PH

Connect R & Y phase B-phase & all GS open

Connect R & B phase V-phase & all GS open

Connect Y & B phase R-phase & all GS open

i .y

Results (OHMS) Zero or low

Yphase & B PH

High

B phase&R PH

High

R phase & Y PH

High

Y phase&B PH

High

B phase & R PH

Zero or low

R phase & Y PH

High

Yphase &B PH

Zero or low

B phase &R PH

High

If the test results are OK, it confirms that marking of the phases are in order. 10.3

Phase Sequence

Once the line is charged from one end, without closing the breaker at the other end the Phase sequence is to be checked from the CVT output using phase sequence meter. In case, there is other feeders available, phase sequence is to be rechecked by the measurement of secondary voltage of both the feeders (new line and available charged line).

Manual on Commissioning Procedure for Transmission Lines

13

Let the secondary voltage of CVT is 110 volts (ph to ph) for both the circuit. In case of correct Phase Sequence the voltage reading shall be as follows: New circuit

Old circuit

Voltage

R· Phase R· Phase

R· Phase y. Phase

0 1 10 Volt (approx.)

R· Phase y. Phase y. Phase

B· Phase

110 Volt (approx.)

R· Phase y. Phase

110 Volt (approx.) 0

y. Phase

B· Phase

1 10 Volt (approx.)

B· Phase B· Phase B· Phase

R· Phase y. Phase

110 Volt (approx.) 110 Volt (approx.)

B· Phase

0

In case the results are not matching the phase sequence is to be rechecked and reconfirmed before closing the breaker.

11.0

ENERGIZA TION

After ensuring the correct phase sequence, the line may be energized by closing the breaker at other end also .

12.0

DE-ENERGIZATION

Instructions about de-energization will be given only if this is part of the test. Otherwise de-energization will be considered part of regular operation.

13.0

OBSERVATION

Visual and audible inspection (look and listen) of the relevant equipment and reading of permanent instrumentation will be made. . The system shall be charged for least for 8 hours. Dur~ng this time continuous monitoring and inspection will be maintained in control room, auxiliary systems areas and switchyards. This will include frequent, schedUled inspection of all equipment and reading of all permanent instruments and recorders, and surge arrester counters, especially system parameters as per standard procedures.

14.0

PASSING CRITERIA

Neither insulation breakdown nor protective system actions must occur. No irregular behaviour like excessive noise, high vibration and high temperature is permitted in conductor and conductors accessorieslhardware fittings . Corona discharges should not be "unreasonable". Local discharges that may be attributable to sharp points shall be carefully located and recorded. After termination of the energization, the equipment shall be closely inspected and rectification, if required, shall be carried out.

Publication No. 292

14

Conductor/conductor accessories in transmission line may also be monitored for corona discharge/ other irregularities on sample basis. No unscheduled changes of system or of equipment are permitted during the 8 hour energized condition. 15.0

DOCUMENT ATION

Records of check list for transmission lines as per sample' format given in Annexure-II are to be maintained for each location. Inspection record prior to handing over the line for energization is to be kept for the complete line as per sample format given in AnnexureIII. Handing over record for energization of line is to be maintained as per sample format given in Annexure-IV. Record of measurement of insulation resistance and continuity test of the line are to be maintained as per sample format given in Annexure-V. Switching and operational activities will be recorded in regular manner in the operator's log. Similarly all readings of penn anent instruments are also to be recorded. Copies of this log notes on special observations from inspections and other measurements will constitute the test records.

15

Manual on Commissioning Procedure for Transmission Lines

ANNEXURE-I INDIAN ELECTRICITY RULES, 1956 CHAPTER VII ELECTRIC SUPPLY LINES, SYSTEMS AND APPARATUS FOR HIGH AND EXTRA-HIGH VOLT AGES The relevant portion of the Indian Electricity Rules, 1956 is reproduced below:

63. Approval by Inspector (1) Before making an application to the inspector for permission (to commence or recommence supply after an installation has been disconnected for one year or above) or high or extra high voltage to any person, the supplier shall ensure that the high or extra-high voltage electric supply lines or apparatus belonging to him are placed in position, properly joined and duly completed and examined. The supply of energy shall not be commenced by the supplier unless and until the Inspector is satisfied that the provisions of Rules 65 to 69 both inclusive have been compiled with and the approval in writing of the Inspector has been obtained by him : Provided that the supplier may energize the aforesaid electric supply lines or apparatus for the purpose oftests specified in Rule 65. (2) The owner of any high or extra-high voltage installation shal1, before makin'g application to the Inspector for approval of his installation or additions there to, test every high or extra-high voltage circuit or additions thereto, other than an overhead line, and satisfy himself that they withstand the application of the testing voltage set out in sub-rule (1) of Rule 65 and shall duly record the results of such tests and forward them to the..!nspector. 65. Testing, Operation and Maintenance (1) Before approval is accorded by the Inspector under Rule 63 the manufacturer's test certificates shall, if tequired be produced for all the routine tests as required under the relevant Indian Standard. (2) No new HV or EHV apparatus, cable or supply line shall be commissioned unless such apparatus, cable or supply line are subjected to site tests as per relevant code of practice of the (Bureau ofIndian Standard) (3) No HV or EHV apparatus, cable, or supply line which has been kept disconnected, for a period of 6 months or more, from the system/or alterations or repair shall be connected to the system until such apparatus cable or supply line are subjected to the relevant tests as per code of practice of (Bureau of Indian Standards). (4) Notwithstanding the provisions of sub-rule (1) to (3) (both inclusive) the Inspector may require certain additional tests to be carried our before charging the installations or subsequently.

16

Publication No. 292

(5) All apparatus, cables and supply lines shall be maintained in healthy conditions and tests shall be carried out periodically as per the relevant codes of practice of (Bureau of Indian Standards). (6) Records of all test, tripping, maintenance works and repairs of all equipment, cables and supply lines shall be duly kept in such a way that these records can be compared with earlier ones; and (7) It shall be the responsibility of the owner of all HV and EHV installations to . maintain and operate the installations in a condition free from danger and as recommended by the manufacturer and/or by the relevant codes of practice of the (Bureau of Indian Standards) and/or by the Inspector). 77. Clearance above Ground of the Lowest Conductor: (1) No conductor of an overhead line, including service lines, erected across a street shall at any part thereof be at a height less than (a)

For low and medium voltage lines

5.8 m

b)

6.1 m

(2) No conductor of an overhead line, including service line, erected along any street shall at any part there of be or a height less than 5.5 m 5.8 m

(3) No conductor of an overhead line including service linl:s, erected elsewhere than along or across any street shall be at a height less than (a)

For low, medium and high voltage lines up to and including 11 ,000 volts, if bare

4.6 m

(b)

For low, medium and high vol tage line up to and including 11 ,000 volts, if insulated

4. a m

(c)

For high voltage line above 11 ,000 volts

5.2 m

(4) For extra-high voltage lines, the clearance above ground shall not be less than 5.2 m plus 0.3 m for every 33,000 volts or part thereof by which the voltage .ofthe line exceeds, 33,000 volts. Provided that the minimum clearance along or across any street shall not be less than 6.1 m. . 78. Clearance between Conductors and Trolley Wires (1) No conductor of an overhead line crossing a tramway or trolley-bus route using trolley wires shall have less than the following clearances above any trolley wire (a)

Low and medium voltage lines Provided that where an insulated conductor suspended from a bearer wire crosses over a trolley wire the minimum clearances for such insulated conductor shall be 0.6 meter

1.2m

Manual on Commissioning Procedure for Transmission Lines

17

(b)

High voltage line up to and including 11,000 volts

2.5 m

(e)

Extra high voltage line

3.0 m

(2) In any case of a crossing referred to in sub-rule (1), whoever lays his line later in time, shall provide the clearance between his own line and the line which will be crossed in accordance with the provisions of said sub-rule provided that if the later entrant is the owner of the lower line and is not able to provide adequate clearance, he shall bear the cost of modification of the upper line so as to comply with this rule. 79. Clearance from Buildings of Low and Medium Voltage Lines and Service Lines (1) Where a low or medium voltage overhead line passes above or adjacent to or terminates on any building, the following minimum clearance fr.om any accessible p.oint, .on the basis of maximum sag, shall be .observed:

(a) For any flat roof, open balcony, verandah roof and lean-to-roof (i) When the line passes above the building a vertical clearance of 2 .5 ill from the highest point, and (ii) When the line passes adjacent to the building a horizontal clearance of 1.2 m from the nearest point, and (b) For pitched roof (i) When the line passes above the building a vertical clearance of2.5 m immediately under the lines, and (ii) When the line passes adjacent to the building a horizontal clearance of 1.2 m. (2)

(3)

Any conductor so situated as to have a clearance less than that specified in sub-rule (1) shall be adequately insulated and shall be attached at suitable intervals to a bare earthed bearer wire having a breaking strength of not less than 350 kg. The horizontal clearance shall be measured. when the line is at a maximum deflection from the vertical due to wind pressure. (Explanation - For thj purpose of this rule, expressi.on "building" shall be deemed to include any structure, whether permanent or temporary.)

80. Clearance from Buildings of High and Extra-high Voltage

~jnes

(1) Where a high or extra-high voltage over head line passes above or adjacent to any building or part of a building it sha11 have on the basis of maximum sag a vertical clearance above the highest part of the building immediately under such line, of not less than (a)

For high voltage line up to an including 33,000 volts

(b)

For extra-high voltage lines

3.7 metres 3.7 metres plus 0.30 metre for every additional 33,000 volts or J1art thereof

Publication No. 292

18

(2) The horizontal clearance between the nearest conductor and any part of such building shall, on the basis of maximum deflection due to wind pressure, be not less than (a).

(b)

For high voltage line up to an including 11 ,000 volts For high voltage line above 11 ,000 volts and up to and including 33,000 volts For extra-high voltage lines

1.2 metres 2 .0 metres

2.0 metres plus 0.30 metre for every additional 33,000 volts orpart thereof

(Explanation- For the purpose of this rule expression "building" shall be deemed to include any structure, permanent or temporary). 83. Clearance: General For the purpose of computing the vertical clearance of all overhead line, the maximum sag of any conductor shall be calculated on the basis of the maximum sag in still air and the maximum temperature as specified by the State Government under Rule 76(2)(d). Similarly, for the purpose of computing any horizontal clearance of an overhead line, the maximum deflection of any conductor shall be calculated on the basis of the wind pressure specified by the State Government under Rule 76 (2)(a) (or may be taken 35° whichever is greater). 86. Conditions to apply where Telecommunication Lines and power Lines are carried on same supports: I. Every overhead telecommunication line erected on supports carrying a power line shall consist of conductors each having a breaking strength of no less than 270 kg. 2. Every telephone used on a telecommunication line erected on supports carrying a power line shall be suitably guarded against lightning and shall be protected by cutouts. 3. Where a telecommunication line is erected on supports carrying a high or extra-high voltage power line arrangement shall be made to safeguard any person using the telephone against injury resulting from contact, leakage or induction between such power and telecommunication lines. 87. Lines Crossing or Approaching each other 1. Where an overhead line crosses or is in proximity to any telecommunication line, either the owner of the overhead line or the telecommunication line, whoever lays his line later, shall arrange to provide for protective devices or guarding arrangements in a manner laid down in the code of Practice or the gl;lidelines prepared by the power and telecommunication Co-ordination Committee and subject to the provisions of the following sub-rules. 2. When it is intended to erect a telecommunication line or an overhead line which will cross or be in proximity to an overhead line or a telecommunication

19

Manual on Commissioning Procedure for Transmission Lines

line, as the case may be, the person proposing or erect such line shaH give one month's notice of his intention so to do along with the relevant details of protection and drawings to the owner of the existing line. 3. Where an overhead line crosses or is in proximity to another overhead line, guarding arrangements shaH be provided so as to guard against the possibility of their coming into contact with each other. Where an overhead line crosses another overhead line, clearances shall be as under. (Minimum clearances in metres between lines crossing each other) SI.

No.

Nominal system voltage

11-66 kV

110- 132 kV

220 kV

400kV

800 kV

1

Low and medium

2.44

3.05

4.5 8

5.49

7.94

2

11 -66 kV

2.44

3.05

4.58

5.49

7.94

3

110-132 kV

3.05

3.05

4.58

5.49

7.94

4

220 kV

4.58

4.58

4.58

5.49

7.94

5

400 kV

5.49

5.49

5.49

5.49

7.94

6

800 kV

7.94

7,94

7.94

7.94

7.94

Provided that no guarding are required when an extra high voltage line crosses over another extra high voltage, high voltage, medium or low voltage line or a road or a tram subject to the condition that adequate clearances are provided between the lowest conductor of the extra high voltage line and the top most conductor of the overhead line ~ crossing underneath the extra high voltage line and the clearances as stipulated in Rule 77 from the topmost surface of the road is maintained),

Publication No; 292

20

ANNEXURE-II SAMPLE CHECK LIST FOR TRANSMISSION LINE

I

DATE OF ENERGISA TlON

NAME OF LINE CIRCUIT A· GENERAL DATA AND INFORMA TION · REGION I DIVISION HEAD QUARTER II VOLTAGE RATING 66 132 III

oIci°

0 D IV

SIC

TYPE OF CIRCUIT

0 0 V VI VII VIII

LENGTH OF LINE TOTAL NOS OF TOWERS TOWER LOCATION NO. TOWER TYPE

0

SIC on DIC TowerD

DIC

Mono polar

KMs . NOs. 2-15'

lS-30"

30-60° dead end

FOR SIC

1:]

BO

CO

DO

FORDIC

DAD

DBD

DCD

DDD

NORMAL EXTN. (METRES S)

+3

+9

+6

+12

1.5

4.5

3.0

Special

D +25

0

0 7.5

6.0

9.0

D [] D D D X

TYPE CONDUCTOR

DRY

D OF

XII

VULNERABLE LOCATION

XIII

CROSSING DETAILS River

0

SINGLE

D

D

D

TWIN

TRIPLE

Railwa

PILE

HR

D

BERSIMIS

OTHERS

D QUAD

OTHER

D

0

D YES

!D

SR

D D D MOOSE

D Power line

BC

ZEBRA

D

NO OF CONDUCTORS IN BUNDLE

FS

PS

D

PANTHER

XI

Location no.

WET

Others

0

+18

D D D 0

LEG EXTN. (METRES)

TOWER FOUNDATION TYPE

KV

BEar

0

0_20

IX

01 I

500 HVDC

O

D

NO

D

MS compression joint

Repair sleeve

Circuit-l

Circuit-l

y line R

(Increase)

(Name)

(Name & Voltage)

(Name)

(Decrease)

(Name)

(Name & Voltage)

(Name)

• Please tick approprIate box for mdlvlduallocatlOn

y

Circuit-2 B

R

Y

B

R

Y

Circuit-2 B

R

Y

B

21

Manual on Commissioning Procedure for Transmission Lines

XIV SL No.

1 a b c d e f g h

2 a b c d e f g h i j 3. a b

4 a b

c d

5 a

b

DETAILED CHECK LIST Status

Description

Yes

No

Remarks Record Deficiencies If any

Foundation Check any damage/ uneven settlement of foundation Check back filling of foundation is properly filled up to the ground level of all legs Check surplus earth! concrete after foundation casting is removed from -.rlatfonn of the tower beyond specified distance as per specification Check crack or break in chimney Check crack or damage to retaining wall! revetment and proper weep holes are provided for flushing water Check that all foundation chimneys are covered with soil and compacted specially in hilly terrain and river! nalas banks up to ground level Check difference in foundation levels are within limit Check for damage to drainage if provided at the toe of the breast wall in hilly area Tower Check for defonned! rusted or damaged tower members Check for missing tower members Check for missing bolts & nuts Check for tighteningof all bolts & nuts Check for punching, Tack welding (at least 10 mm circular length at 2 or 3 points) and zinc rich paint coating of bolts & nuts Check filling of extra holes in tower members with bolts & nuts except hQles for step bolts below ACD Check verticality of tower Check that no tower leg is suspected to be in sinking land or soil erosion field of river·bank, if so , proper adequate protection has been provided Check fix ing & correctness of all tower accessories namely danger/ number/circuit/phase plate! step bolts and anti climbing device (ACD) Check correct sequence of fixing of phase! circuit plate at transposition towers Insulators/Strings Check that all the insulator discs are free from any damage Check for unusual deflection in suspension strings and if found, should be . rectified Removal ofT&P and foreign materials Check temporary earthing! guys used during stringing and jumpering are removed Check all foreign materials on tower, e.g., dense spider, webs, any handling rod! wire, kites, bird nests and left over T&P on tower! cross-ann are removed Check proper aviation warning signals on towers above 45 meter height Check that intemational orange & white paints have been applied on towers which fall in aviation route Ha rdwa re Fittings Check that hardware fittings like corona control ring! arcing horns etc. are provided as per the approved drawing! specification Check the condition cotter pins and ensure that proper size cotter pins have been provided as p_er the approved drawing.

of

. - --

-

Publication No. 292

22

Sl. No.

Description

c

Check that nos. of insulators for string is less by one no. As compared to no. of discs in normal string (up to 220 kY) for last few spans say 1.5 km. And it should be in line with the approved drawings/ specification issued by engineering dept!. Check that all insulators are thoroughly cleaned

d

6 a b

c d

Yes

Conductor and its Accessories ChecK that the conductors/ sub-conductors are free from scratches/ rubs Check that all joints on conductor/ earth wire are away from the tower as per the specified distance (at least 30 m) and joints are as per the approved drawings/ specification Check that not more than one joint in a sub conductor/ earth wire is provided in one span. Check that no mid span joints or repair sleeves are provided in major crossings for highway, Railway and major rivers.

e

Check that all mid span joints on conductors/ Earth wire and repair sleeves of compression type are free from sharp edges rust and dust

f

Check that conductor is properly clipped in the suspension clamp

g

Check that armour rods are provided on suspension towers

h

Check that spacers are provided between two sub conductors on 'each phase as per the spacer as per the approved spacering chart! specification

i

Check that all the spacers are properly tightened and free from any external damage.

j

Check that spacing of vibration dampers from the tower and spacing between damper to damper where two vibration dampers provided are properly fixed and tightened as per the damper placement chart! specification Check that all thejumpers are properly fixed and torque tightened as per the approved drawing! specification. Spacers are also provided wherever applicable.

k

Status '

I

Check that all conductors/ earth wires/ hardware fittings are free from all foreign material like dead bird! fallen tree! bird nests etc

7 a

Miscellaneous Clearances Check that right of way is not obstrueted by any tree etc (Refer Table-I)

b

Check that mid span clearance between top conductor and earth wire is adequate (Refer Table-2)

c

Check that lowest conductor and ground clearance is more than the required minimum clearance (Refer Table-3)

d

Check that sag and tension of the section of the line is inline with sag and tension calculation chart! specification approved by Engg.

e

Check for difference in 3ag between sub-conductors of the bundle.

f

Check that copper bonds are provided on suspension clamps/ tension clamps of earthwire to connect earthwire to tower body

No

Remarks Record Deficiencies lfany

23

Manual on Commissioning Procedure for Transmission Lines

Table 1: Right of way at different voltage level as per forest conservation act 1980 Line voltage (k Y) ROW width (m)

Table 2: Clearance between conductor and ground wire "at mid span" as per clause no. 4.10.2 of CBlP Transmission Line Manual Line voltage (kY)

Table 3: Minimum ground clearance for different voltage level

66

Line voltage (kY)

110

132

7 (a) Measurement of minimum clearance when the line is crossing telecommunication line S an (Tower location nos.)

Clearance (mm)

Note: Minimum clearance between conductor of power line for different voltage and telecommunication line are as under: Line voltage (kV) Clearance (mm) 7 (b) MeasUJ;ement of minimum clearance when line is crossing another Power line Span (Tower location nos.)

Crossing Power line details (Name & voltage)

Clearance (mm)

Note: Minimum clearance between power lines crossing each other: SL No .

Line voltage (kY)

11-66 (mm)

110-132 (mm)

220

400

500 HYDC

765

110-132

2440 3050

3050 3050

4580 4580

5490 5490

6790 6790

7940 7940

3

220

4580

4580

4580

5490

6790

7940

4

400

5490

5490

5490

5490

6790

7940

500 HYDC 765

6790

6790

6790

6790

6790

7940

7940

7940

7940

7940

7940

7940

I

Up to 66

2

5 6

7 (c) Measurement of minimum clearance when line is crossing railway track Clearance (mm) Note: Minimum clearance when pOlVer/ine crossing railway track: Line voltage! clearance

66

132 kY

220 kY

400 kV

Above track (mm) Over crane (mm)

14100 2000

500 kY

765 kY

HYDC

kY

14600 2500

15400 3500

17900 6000

19300 7250

23400 11500

Publication No. 292

24

8. Measurement of contact resistance of jumper in case of tension towers by the help of micro-ohm meter (minimum 200 amps). The value should not be more than 10 to 20 micro ohm Span location R-Phase

Circuit-! Y-Phase

I I

I

I I

B-Phase

R-Phase

I

I I

Circuit-II I B-Phase Y-Phase

I

I

I

9. Measurement of tower footing resistance by earth resistance tester or any other suitable instrument (The value should not be more than 10 ohms)

I Value (Ohms)

I Location

I Remarks

The above inspection and measurements are carried out in the location mentioned above and the remaining activities, temporary ar.angements etc. are documented (Sample format Annexure-ill) Contractor representative

agency

Supplier representative

agency

Erection

Signature Date Name Organization Notes: 1.

2. 3.

Thisformat is to befilledfor each tower location. This format is to be kept at group head quarter with a copy to regional head quarter This format to be signed not below the level of engineer and important locations like river crossing. railway crossing. power line crossing etc. are to be countersigned by Engineer In-charge for the Owner and in-charge of the working agency

25

Manual on Commissioning Procedure for Transmission Lines

ANNEXURE-III Date of energisation

Circuit

Name of line

SAMPLE FORMAT FOR INSPECTION RECORD PRlOR TO HANDING OVER FOR ENERGISATION LIST OF REMAINING ACTIVITIES LIST OF TEMPORARY ARRANGEMENTS Region: Section SI No

NB/C

DHQ Tower No

Observation Sign Date

Location From

I To I

Comlletion Sign Date

Inspection Sign Date

Description

Contractor representative

agency

Erection

Line In- charge

Signature Date Nilme Organization Details of sections in this format: (a) (b) (c) (d)

Outstanding activities remairll ng in any part of the line A list of temporary arrangenfents introduced. Checklist records properly completed and signed as per format no: MRIOSILINEI Original tracing of Profile, Route alignment, Tower Design, Structural Drawings, Bill of material, Shop drawings, Stringing Charts indicating initial and final sag, etc., of all towers submitted to the Owner.

Note: This dOCllment is Quarter)

10

be retained at DHQ (Divisional Head Quartel~ with copy

to

RHQ (Regional Head

Publication No. 292

26

ANNEXURE-IV Name of line

Date of energisation

Circuit

SAMPLE FORMAT FOR HANDING OVER RECORD FOR ENERGISA nON

A: GENERAL DATA AND INFORMATION

Details : Status SI No

Description

Yes

No

Remarks Record deficiencies ifany

Check list of entire section of the line along with towers and accessories under this division have carried out and documented in the format as per Annexure-II (This format retained at DHQ) . Inspection has been carried out in all towers and the outstanding issues along with temporary arrangements are documented in the format as per Annexure-lII (This format retained at DH·Q ) No . of remaining activitiesl points are listed below and these are minor in nature and do not stop charging the line

I

2

3

HANDING OVER CHECK POINTS

Section

Points according to Annexure II (nos of remaining activities)

Points completed and confirmed Date

Sign

Points accepted Date

Sign:

A

B C D SL No.

4

5

Description

All electrical and ground clearances are as per the Approved drawings issued from CCI Engg. Department have been checked and no deviation has been noted All man and material and temporary antitheft electrical connection, if any, have been removed from all the locations under This division

Status Yes

NO

Remarks Record deficiencies any

if

Manual on Commissioning Procedure/or Transmission Lines

6

7

8

9

Electrical clearance has been received from CEA electrical inspector for charging of the line vide order no: (copy enclosed) Dated: PTCe clearance has been received from ministry of communication department for charging of the line vide order no : (copy enclosed) Dated: All statutory rules and regulations pertaining to line charging has been carried out and nothing is pending All working agencies involved In construction! erection of this Line are intimated regarding charging of this line and further work, if any, are to be carried out only after avai li ng the Permit to Work (PTW) from the Concerned sub-station O]Jerating staff

10 The above line is handed over for energisation with! with out remaining activities Signature Date Name Designation

Handed over by

Accepted for Energisation

Line in-charge

Commissioning in-charge

Note: For details o/section, please refer ,;ample/ormat enclosed at Annexure-III o/this document

27

Publication No. 292

28

ANNEXURE-V Date of energisation

Circuit

Name of line

SAMPLE COMMISSIONING TEST FORMAT A: GENERAL DATA AND INFORMATIONS:

I Region I I Voltage rating I

Total no. of to wers

I DHQ I I

I I KV

I Type of towers 1 Tower locations I

I

I SIC From

I

I

Total length

1 DIC I

To

I km

I

I

I

Details: STATUS YES NO

DESCRIPTION

S1. No.

REMARKS Reco r d Deficiencies

if

aIlL I

2

3

4 5

6

7 8

9

The entire section of the line handed over for energisation asper prescribed format on Dated: No. of remaining activitiesl points are listed in prescribed fonnat and these are minor in nature and do not stop charging the line All the equipment involved in charging of the line are tested and test results are documented as per the precommissioning procedure for bay equipment All the protections are checked and put into service and documented Electrical clearance has been received from CEAt state electrical inspector for charging of the line vide order dated: (copy to be enclosed) no : PTCC clearance has been received from ministry of communication department for charging of the line vide order no: Dated: (copy to be enclosed) All statutory rules and regulations pertaining to line charging has been carried out and nothing is pending Man and material and temporary antitheft electrical connection , if any, removed from all the locations All working agencies inVOlved in construction/ erection of this line and sub-station equipments are intimated regarding charging of this line & bay and further work, if any, are to be carried out only after availing the permit to work (PTW) from the concerned sub-station operating staff

B. MEASUREMENT OF INSULATION RESISTANCE FOR LINE (usin g 5 kV/10 kV motorized meggery. Between R-Phase and ground Y-Phase and ground B -Phase and Ground R-Phase and Y-Phase Y-Phase and B-Phase B-Phase and R-Phase

Measured value In m - ohm

Remark

Condition All ground switches at other end are opened. Min. value should be approx. 150 Mega ohm (value may change with weather condition)

29

Manual on Commissioning Procedure for Transmission Lines

C. CONTINUITY TEST OF T HE LINE (a) For p hase marking confirmation Sending end conditions

Receiving end megger between

CLOSE R - PHASE G

R - PHASE & GROUND

OPEN Y - PHASE GS OPEN B - PHASE GS OPEN R - PHASE GS

Measured value in ohms

Y - PHASE & GROUND B - PHASE & GROUND R - PHASE & GROUND

Remark LOW HIGH HIGH HIGH

CLOSE Y - PHASE OS

Y - PHASE & GROUND

OPEN B - PHASE GS:

B - PHASE & GROUND

HIGH

OPEN R - PHASE OS

R - PHASE & GROUND

HIGH .

OPEN Y - PHASE GS CLOSE B - PHASE GS

CONNECT R & Y PHASE, ALL GS OPEN

CONNECT R & B PHASE, ALL OS OPEN

Cu,,,NECT Y & B PHASE, ALL OS OPEN

Y - PHASE & GROUND B - PHASE & GROUND

LOW

HIGH LOW

R-PHASE & V-PHASE

LOW

V-PHASE & B-PHASE

HIGH

B-PHASE & R-PHASE

HIGH

R-PHASE & V-PHASE

HIGH

V-PHASE & B-PHASE

HIGH

B-PHASE & R-PHASE

LOW

R-PHASE & V-PHASE

HIGH

V-PHASE & B-PHASE

LOW

B-PHASE & R-PHASE

HIGH

Notes: 1.

2.

If the lest values are as per"ihe remark, phase marking at both ends are correct. This test is to be done if the megger value do not show short circuit of the line with ground or between phases in lR measurement

D. MEASUREMENT OF PHASE SEQUENCE After clos ing the breaker from one end only the line can be charged. (a)

Check the phase sequence at other end using phase sequence meter by connecting at the secondary of the CVT

I Ok (b)

I NotOK

Check the phase sequence using multi -meter in case of a charged sub-station at the secondary of the CVT (existing line and new line) in the control panel as per the measurement indicated below:

30

Publication No. 292

Voltage measurement between Charged New circuit old circuit R-phase R:phase Y-phase R:jJhase B-phase R-phase R-phase Y-phase Y-phase Y-phase B-phase Y-phase R-phase B-phase YjJhase B-phase B-phase B:Rhase

51. No.

I

2 3 4 5 6

7 8 9

Rema rks

Measured voltage (volts)

In case of correct phase sequence, the vo ltage measured between R & R phase, Y & Y phase, B & B phase of old charged Iine and newly charged circ uit wil l be zero or very small and all other me'a surements will show full line CVT phase to phase secondary voltage

Once the correct phase sequence is established, the charging instruction rece ived from design! engineering deptt. to be followed and properly documented regarding status of various parameters wi th other lines and generators, if any.

E.

Charging instruction no :

Dated :

(Copy enclosed)

Charging details :

Date :

Time:

Pre-charging conditions for sending end

J

(a)

Vo lta ge

(b)

Generator details UnitNo

kV

Capacity

MW Generated

MVAR Generated

Remarks

I

2 3 4 (c)

Lines connected: 51. No. I

Name of line

MVAR

MW

Line Reactor In service CajJacity

2

3 4 (d)

N o. and ra t ing of ICTs connected 51. No.

Rating Voltage

MW MVA

Tertia ry reactor M VAR

31

Manual on Commissioning Procedure for Transmission Lines

(e)

Status of Bus Reactor, if any

I SL No. (iii)

On charging condition Details Voltage MVAR Open end voltage

(iv)

Status

Rating

Sending end

Receiving end

N/A N/A N/A

Post charging condition Details Voltage MW MVAR

Sending end

Receiving end

The line has been! not has been successfully test charged with or without following operational constraints: 1. 2. 3.

4.

Signature Name Designation Organization Agency

Line erection

SIS erection

Line supplier

Line In-cha~e

SIS In-charge