Study of the Transient Voltage Distribution of the Transformer Windings Caused by VFTO

doi:10.11985/2018.10.002

Abstract

Abstract:

The very fast transient overvoltage (VFTO) generated by disconnector operation in gas insulated switchgear (GIS) can cause insulation faults of GIS equipment and electrical equipment connector to it, especially power transformer. In this paper, VFTO at representative position caused by disconnected operation in GIS is calculated and simulated with EMTP, and the characteristic amplitude values of VFTO are analyzed, the VFTO is applied to the transformer windings, and the transient voltage distribution of the transformer windings is analyzed, the potential gradient between the coils and the turns is obtained, the insulation faults of the transformer windings are found, which is in the forward end of the transformer windings.

Key words: Very fast transient overvoltage (VFTO), gas insulatecl switchgear (GIS), transient voltage distribution, EMTP, multi-condultor toransmission line (MTL) model

CLC Number:

TM41

Gao Youhua,Song Jia,Du Hanwen,Gao Youfeng,Li Yanbin. Study of the Transient Voltage Distribution of the Transformer Windings Caused by VFTO[J]. Journal of Electrical Engineering, 2018, 13(10): 6-10.

Figures/Tables 9

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	平均值(pu)	最大值(pu)	峰值电压发生时间/μs
电源侧	1.56	1.91	3.3
负载侧	1.87	2.41	4.4

元件	模型说明	参数
变压器	入口电容	C = 5 000pF
套管	对地电容	C_B= 300pF
断路器	n个等效串联电容;端口集中电容	C_n = 30pF C₀= 250pF
封闭母线	分布参数传输线（单位长度的电感、电容）	L₀= 0.25μH C₀= 44.5pF