Asynchronous Motor Contribution In Iec 60909 Sc Calculation: Etap Knowledge Base

ETAP Knowledge Base

Asynchronous Motor Contribution in IEC 60909 SC Calculation Description: Asynchronous motor I"k calculation in ETAP IEC 60909 SC calculation Category:

Short-Circuit IEC

Type:

Calculation

Keywords:

Short-Circuit Calculation, Motor Contribution, IEC Standard, IEC 60909

Question: How does ETAP consider motor contribution in low-voltage power supply systems in IEC 60909 SC calculations? Answer: It does not matter how small the motor is when it comes to determining its contribution to I"k. ETAP will consider all motor contributions to the fault location no matter their size and location. ETAP uses the LRC and %PF for LRC to determine the Z of the motor in IEC 60909 calculations. The contribution of the motors only is judged based on percentage of the total current when it comes to the determination of the breaking current. If the motor contribution is less than 5%, then the fault is not considered as near to generator. If it is more than 5%, then it is considered as far from gen (keep in mind that there are other factors like actual synchronous generator contributions to consider to determine the near/far from generator for a fault).

This document is confidential and proprietary to Operation Technology, Inc. and may not be reproduced, published or disclosed to others without the written authorization of Operation Technology, Inc., 17 Goodyear, Suite 100, Irvine, CA 92618, USA. © 2011 by Operation Technology, Inc. All Rights Reserved.

© Operation Technology, Inc.

Page 1 of 1

ETAPKB