Treatment and Analysis of 500kV Capacitor Voltage Transformer Fault

doi:10.11985/2018.12.005

Abstract

Abstract:

As for the abnormality of secondary voltage of 500kV capacitor voltage transformer (CVT) in operation, it is checked clearly by way of site inspection and disassembly at factory that the cause for such abnormality is due to the protection arrester with both ends of the compensation reactor in CVT fault and insulation strength reduction of arrester. The reasons that the secondary voltage value of CVT is small and the phase lead in CVT are qualitatively analyzed by the phasor. Combined with the test data of the equipment, the secondary output voltage of fault CVT with load is quantitatively analyzed.

Key words: Capacitor voltage transformer, protection arrester, qualitative analysis of phasor, secondary output voltage

CLC Number:

TM451

Gu Yongdi,Li Xianpeng,Dong Xinfeng,Peng Chenguang. Treatment and Analysis of 500kV Capacitor Voltage Transformer Fault[J]. Journal of Electrical Engineering, 2018, 13(12): 24-30.

Figures/Tables 16

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电压	A相	B相	C相
监控设备/kV	294.95	90.85	294.63
保护装置/V	59.00∠0°	19.13∠-53°	59.00∠120°

CVT二次绕组	第一绕组	第二绕组	第三绕组	开口三角形绕组
绝缘电阻/MΩ	≥2 000	–	≥2 000	≥2 000
是否合格	合格	–	合格	合格

组分名称	含量/(μL/L)
H₂	28.92
CH₄	4.14
C₂H₆	1.53
C₂H₄	1.16
C₂H₂	0
总烃	6.83
CO	109.39
CO₂	485.02

项目	C₂H₂/ C₂H₄	CH₄/H₂	C₂H₄/C₂H₆
比值	0	0.143	0.758
对应编码	0	0	0
故障类型	低温过热（低于150℃）

电容	主绝缘电阻 /MΩ	tgδ(%)	C（实测） /pF	C（初始） /pF	ΔC_x(%)	C（总）/pF
C₁₃	40 000	0.064	15 430	15 480	-0.32	5 149
C₁₂	40 000	0.076	15 470	15 440	0.19
C₁₁	40 000	0.067	17 740	17 700	0.23
C₂	10 000	0.106	119 000	118 900	0.08