1、16 April 2008 SH95734IEEE Std C37.20.7-2007Errata to IEEE Guide for Testing Metal-EnclosedSwitchgear Rated Up to 38 kV for Internal Arcing FaultsSponsorSwitchgear Committeeof theIEEE Power Engineering SocietyCorrection SheetIssued 16 April 2008Copyright 2008 by the Institute of Electrical and Electr
2、onics Engineers, Inc. All rights reserved.Published 2008. Printed in the United States of America.This correction sheet may be freely reproduced and distributed in order to maintain the utility and currencyof the underlying standard. This correction sheet may not be sold, licensed, or otherwise dist
3、ributed for anycommercial purposes whatsoever. The content of this correction sheet may not be modified. Contents ofthis correction sheet have been incorporated into the second printing of IEEE Std C37.20.7-2007.Correction Sheet to IEEE Std C37.20.7-2007SH95734 16 April 2008Subclause 5.2.4 contains
4、two software conversion errors. The “610“ in the third sentence and the “620“ in the forth sentence are incorrect. Replace the “610“ with “10%“ and replace the “620“ with “20%.“5.2.4 Frequency of the test supply The duration of the test must be considered when setting the frequency of the test curre
5、nt and voltage. Thearc energy is significantly affected by frequency when the arc duration is less than 50 ms. Where fast actingprotective devices will limit the rated arcing duration (duration of test arc) to 50 ms or less, the frequency atthe beginning of the test shall be the rated frequency of the equipment 10%. For a rated arcing durationgreater than 50 ms, the frequency at the beginning of the test shall be the rated frequency of the equipment20% and the frequency of the waveform should not deviate from the initial value by more than 8% for theduration of the test.
