主变500kV环氧树脂浸纸套管介损异常原因研究

2001年至今,国内有多家电厂主变500 kV的12具环氧树脂浸纸套管发现介损异常,其中3具已予以更换.通过理论分析、现场实测,以及实验室研究,揭示了环氧树脂浸纸主变高压套管介损异常的原因主要是由于两种不同介质的界面极化所致,建议只要采取额定运行电压下持续运行一段时间的方法,即可使其介损恢复正常.对于该型套管的介质异常应.同时监测介损异常套管的电容量,以作出正确的判断.

Abnormal dielectric loss of high voltage epoxy bushings for main transformers

It is recorded that since the year of 2001,12 high voltage epoxy bushings of main transformers in China were found to have abnormal dielectric loss,and 3 of them were replaced.Through theoretical analysis,field measurement and lab study,it is found out that the abnormal dielectric loss is caused by interface polarization of two different dielectrics.The measure for resuming the normal dielectric loss of the bushings is put forward:raise the main transformer voltage to its normal value from zero,keep the transformer operating at its normal voltage for some time,and then lower it again.