阶梯电压下变压器匝间绝缘局部放电试验研究

对于变压器绕组而言,轻微匝间放电的发展可能会造成匝间短路甚至更严重的后果。因此,对变压器绕组匝间局部放电的发展进行深入研究具有重要意义。在实验室内构建了变压器匝间绝缘局部放电试验平台,参照500 k V电力变压器线圈绝缘处理工艺要求,设计并制作了匝间绝缘局部放电试验模型线圈,采用逐级升压法对模型线圈施加试验电压,利用数字式局部放电检测仪进行局部放电信号采集,在室温下对变压器匝间绝缘局部放电特征量和二维图谱信息进行了系统的研究。得出了不同加压持续时间下脉冲最大幅值、脉冲平均幅值、脉冲重复频率和脉冲功率的变化特征以及二维图谱的相位分布信息。

Partial discharge tests and researches in power transformer interturn insulation under step-stress

For the transformer winding,slight interturn discharge may cause interturn short circuit or even more serious consequences.Therefore,it is significant to study the development of partial discharge in transformer windings.Transformer turn to turn insulation partial discharge test platform was constructed,referring to 500 kV power transformer coil insulation processing requirements,interturn insulation partial discharge test model coil was designed and fabricated,step-stress tests were applied to coil models,the digital partial discharge detector was used for partial discharge signal acquisition,interturn partial discharge characteristics,two-dimensional phase distribution were studied at room temperature.From the results,the variable characteristics of the pulse maximum magnitude and average magnitude,pulse repetition rate,pulse power and partial discharge messages of two-dimensional phase distributioncan be obtained in step-stress tests of different step-up keeping time.