油中微水对变压器匝间放电的影响

Influence of Micro-water on Partial Discharge Between Windings in Transformers

为了研究微水对油纸绝缘匝间放电的影响,在实验室建立了匝间放电试验平台。模拟了变压器油微水体积分数为11×10-6和28.6×10-6的匝间放电,采用恒压法研究了从起始放电到绝缘击穿的整个过程,使用常规脉冲电流(CIC)测量方法检测局部放电的信息。对所采集的CIC信息进行了放电次数和平均放电量进行统计分析,可以将匝间放电划分为4个阶段:起始放电阶段、放电发展阶段、放电严重阶段和放电严重阶段。试验结果表明:1)微水体积分数为11×10-6的变压器油起始放电电压高于微水体积分数为28.6×10-6的变压器油;2)微水体积分数为11×10-6的变压器油与体积分数为28.6×10-6的变压器油相比,单位时间内的各阶段的放电次数和视在放电量前者小于后者;3)微水体积分数为11×10-6与28.6×10-6的变压器油相比,前者放电持续时间长,后者放电持续时间短。

In order to study the influence of micro-water on the partial discharge（PD） between windings,a discharge test assembly was established to simulate PD between winding.Long-term laboratory tests under 11×10^6 and 28.6×10^-6 were conducted to study the PD evolution from its inception to the eventual occurrence of break-down.By using constant voltage application,PD was detected by conventional impulse current（CIC） signals.The parameters of PD number and average PD amplitude were obtained.Based on the two parameters,the PD evolution process could be divided into four stages： initial stage,developing stage,serious stage and dangerous stage.As a result,in the micro-water oil at 11×10^-6,the initial voltage is much higher,the duration is longer,and the PD number and quantity of apparent discharge are less than that at 28.6×10^-6.