IEEE C57.19-1995 pdf download IEEE Guide for Application of Power Apparatus Bushings
1.2 Purpose
The purpose of this guide is to present general information and recommendations for the application ofpower apparatus bushings when incorporated as part of power transformers, power circuit breakers, and iso.lated-phase bus. The loading model developed in this guide is based on oil-impregnated, paper-insulatedcapacitance-graded bushings. Similar loading models could be developed for other bushing constructions.
2.References
The following standards form a part of this guide to the extent specified in this document:
IEEE Std 1-1986 (Reaff 1992), IEEE Standard General Principles for Temperature Limits in the Rating ofElectric Equipment and for the Evaluation of Electrical Insulation (ANSI).2
IEEE Std 4-1978, IEEE Standard Techniques for High-Voltage Testing (ANSD.3
IEEE Std 100-1992, The New IEEE Standard Dictionary of Electrical and Electronics Terms (ANSI).
IEEE Std C37.04-1979 (Reaff 1988), IEEE Standard Rating Structure for AC High-Voltage Circuit BreakersRated on a Symmetrical Current Basis (ANSI).
IEEE Std C37.010-1979 (Reaff 1988),IEEE Application Guide for AC High-Voltage Circuit Breakers Ratedon a Symmetrical Current Basis (including Supplement IEEE Std C37.010d) (ANSI).
IEEE Std C37.010b-1985,Supplement to IEEE Std C37.010-1979.
IEEE Std C37.010e-1985, Supplement to IEEE Std C37.010-1979
IEEE Std C37.23-1987 (Reaff 1991),IEEE Standard for Metal-Enclosed Bus and Calculating Losses in Isolated-Phase Bus (ANSI).
IEEE Std C57.12.00-1993, IEEE Standard General Requirements for Liquid-Immersed Distribution, Powerand Regulating Transformers (ANSI).
IEEE Std C57.19.00-1991, 1EEE General Requirements and Test Procedures for Outdoor Apparatus Bushings(ANSI.
IEEE Std C57.19.01-1991, IEEE Standard Performance Characteristics and Dimensions for Outdoor Apparatus Bushings.
IEEE Std C57.92-1981 (Reaff 1991), EEE Guide for Loading Mineral-Oil-mmersed Power TransformersUp To and Including 100 MVA with 55 C or 65C Winding Rise (ANSI).
3. Definitions
For definitions of terms used in this standard, see IEEE Std C57.19.00-1991 and 1EEE Std 100-1992
4.Thermal loading above nameplate rating for bushings applied on powertransformers
4.1 General
The thermal loading capability of bushings varies with the way they are loaded, the way they are designedand the ambient conditions in which they are applied.
4.1.1 Basis of rating and rationalization of thermal requirements rating
Capacitance-graded.paper-insulated bushings that, at rated current, meet the requirements of IEEE StdC57.19.00-1991 and earlier versions of that standard may be applied in either 55 °C or 65 “C rise transform-ers. IEEE Std C57.19.00-1991 and IEEE Std C57.12.00-1993 state that the temperature of the oil in whichthe lower end of the bushing is immersed shall not exceed 95 C when averaged over a 24 h period. Trans-former loading shall conform to IEEE Std C57.92-1981
41.1.1 Operation abovetemperature
in conjunction with a 65 °C average winding rise rated transWhen operating a bushing atratedcunenformer. the hottest-spot itemperature of the bushing is limited to a 65 °C rise over ambient or a 105 °C totaltemperature because of the use of temperature index 105 insulating paper for the bushing condenser. If itshould be determined that a transformer develops a top oil rise of 65 °C at rated current when operating in a40 °C ambient, the hottest-spot temperature of the bushing can be expected to exceed 105 “C. In addition.transformers can be expected to have bushing temperatures above 105 °C when loaded in accordance withIEEE Std C57.92-1981. In each instance, the normal life expectancy of the bushing will be shortened by the
IEEE C57.19-1995 pdf download
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