500kV变压器局部放电试验的分析处理

Analysis of partial discharge test of 500 kV transformers and the treatment

介绍了对出厂局部放电试验不合格的某500 kV变压器的多次处理和分析试验的情况,确定局部放电量偏大的原因是调压线圈内部固体绝缘存在大量封闭性气泡,解体验证也予以证实。实践表明,对于局部放电量较小,(仅为数百pC)的内部缺陷,难以定位,需要综合放电波形和放电特性各个要素,结合试验分析推理,才能找到缺陷部位。

The repeated treatment, analysis and experiments of a 500 kV transformer failed in the factory partial discharge （PD） test are introduced. It is finally identified that the excessive partial discharge amount is due to a lot of bubbles inside the internal solid insulation of the voltage-regulating coil, and the conclusion was verified by disassembling of the equipment. Practice shows that common methods are ineffective to locate the internal defects with only several hundred pC of PD and the defects can only be found combining every factor of discharge waveforms and characteristics and based on experimental analysis.