1、IEEE Std 1680-2006IEEE Standards Interpretations forIEEE Std C57.19.00 -2004IEEE Standard General Requirements and Test Procedure for Power Apparatus Bushings Copyright 2009 by the Institute of Electrical and Electronics Engineers, Inc. Three Park Avenue New York, New York 10016-5997 USA All Rights
2、Reserved.This is an interpretation of IEEE Std C57.19.00-2004. Interpretations are issued to explain and clarify the intent of a standard and are not intended to constitute an alteration to the original standard or to supply consulting information. Permission is hereby granted to download and print
3、one copy of this document. Individuals seeking permission to reproduce and/or distribute this document in its entirety or portions of this document must contact the IEEE Standards Department for the appropriate license. Use of the information contained in this document is at your own risk.IEEE Stand
4、ards Department Copyrights and Permissions 445 Hoes Lane, P. O. Box 1331 Piscataway, New Jersey 08855-1331, USAFebruary 2009 Interpretation Number 1:Topic: DC bushings IEEE Std C57.19.03-2005 limits the air side connection to 70 oC ie 30 oC above the maximum Ambient temperature of 40 oCInterpretatio
5、n Request #1 http:/standards.ieee.org/reading/ieee/interp/C57.19.00-2004.html (1 of 3) 2009/02/13 6:17:10 PMIEEE Std 1680-2006The question posed was: “Why does the DC bushings IEEE Std C57.19.03-2005 limit the air side connection to 70 oC ie 30 oC above the maximum Ambient temperature of 40 oC?“Disc
6、ussion : There was a very good discussion on the topic. It was realized that the neither the IEEE relevant standards nor the IEC ones adequately address the problem.It was thought that the limit was set low so as to not add heat to the bushing and thus not impact its thermal performance. There had b
7、een a study done in the past about the high number of DC Bushing failures and the dielectric test values were recommended to be 115%of the transformer test value.This is probably a typical struggle between the supplier who wants to get the maximum out of a bushing and the user who wants a more conse
8、rvative number for longer life.Agreement: There appears to be general agreement that the number of 70 oC is too low.Proposal: For the purpose of a reply I would propose to keep itsimple and put more details into the revision of the standard. Wording proposed is as follows:“After review, the IEEE DC
9、Bushing IEEE Std C57.19.03-2005 concurs that the air side terminal is allowed to go to 90 oC ( including the conductor one metre away from the connection which shall not vary more that +/- 5 oC) providing the hot spot temperature of the bushing does not exceed 105 oC for an Oil Impregnated Paper (OI
10、P) DC Bushing, This area is under review in the standard and may change.“It is advisable to contact your OEM DC bushings supplier who may be able to provide more specific details.Interpretation Response #1That clause did not change from the 1991 document and there were not any discussions on it duri
11、ng the Working Group meetings for the 2004 document. With that said, and not having been involved with the development of the 1991 document, the following is offered:Unlike the other equipment you listed, OIP (oil impregnated paper) bushings have the inboard http:/standards.ieee.org/reading/ieee/int
12、erp/C57.19.00-2004.html (2 of 3) 2009/02/13 6:17:10 PMIEEE Std 1680-2006end immersed in transformer oil with temperatures of 65 degrees K rise over ambient or 95 degrees C. The paper insulation system is limited to a temperature of 105 degrees C. OIP bushings cannot use thermally upgraded Kraft pape
13、r because that paper does not allow stable power factors for the bushing. Above that temperature the paper will experience a loss oflife.This is why the connection terminals are limited as stated in the document.Solid dielectric bushing (ERIP), do not use oil so they can handle higher temperatures,
14、however, today, the vast majority of HV bushings are OIP.Back to Available IEEE Standards Interpretations Online Copyright IEEE-SAContact IEEE-SAFor questions or comments, please contact the IEEE-SA Webmaster.http:/standards.ieee.org/reading/ieee/interp/C57.19.00-2004.html (3 of 3) 2009/02/13 6:17:10 PM
