电容式电压互感器介损增长异常分析

在电容式电压互感器预防性试验中,发现介损增长异常。对其设备提高试验电压,随着电压从10 kV升高至81 kV,介损下降到0.045%,电容量增大4.42%,当电压继续升高至100 kV,介损及电容量不再变化。通过计算及解体试验证实有6个电容击穿。分析结果表明:由于电容在制造过程中真空度未达到要求,发生局部放电,电容未完全击穿,电阻增大,导致介损增长异常。

Abnormal Growth Analysis of Dielectric Loss Factor inCapacitor Voltage Transformer

Dielectric loss grew abnormally in the prophylactic test of capacitor voltage transformer. Dielectric loss was reduced to 0.045% and electric capacity was increased by 4.42% when the test voltage of the device was increased from 10 kV to 81 kV. When test voltage was increased to 100 kV, dielectric loss and capacitance no longer changed. Six capacitors were found breakdown by the calculation and disassembling analysis. Results indicated that the vacuum degree of capacitors in the manufacturing process does not meet the requirements, which produced partial discharge, broken down the capacitance incompletely, and increased the resistance, resulted in abnormal growth of dielectric loss.