灯泡贯流式水轮发电机组的局放在线监测

Application of PD Monitoring System in Bulb Flow-type Generator

针对水轮发电机组结构及汇流母线排走线方式的特点,选择发电机每相高压出线处为系统监测点,利用双安装传感器定向耦合实现干扰脉冲抑制。该系统分别在电站6台发电机主引出线上安装近、远端两路传感器(6只/每台机组),耦合放电信号,经过信号的选通、滤波处理后进入监测系统,利用软件进行时延幅值判别,提取放电信号,并进行二维、三维谱图分析。对比分析了现场测到的放电信号与干扰信号在时域及幅值上的差别,验证了抗干扰方法的有效性。自第一台机组并网发电以来,系统运行稳定、操作方便,所测结果与预试数据基本一致。

The partial discharge on-line monitoring system developed by XJTUSP Boyuan Electric corporation（Ltd） has been installed in the 6 bulb flow-type hydro-generators in Honghua hydro power station. Based on the mechanism analysis of partial discharges inside or outside stator winding insulations of generators and the summary of the research status about on-line PD monitoring techniques in recent years, a set of on-line PD measurement is developed in this paper. While designing this system, several on-site conditions such as the structure characteristics of waterturbine generator set, the detecting position, the wiring style of isolated phase bus （ IPB）, etc. , are considered and the noise suppressing methods are focused on the technique of ＂pulse tlme-delay identification＂ which is based on installing sensor pair for every phase. There are two groups of sensors installed in the near end and far end of the leadout wire respectively（ six sensors per generator）, the signals coupled by the sensors pass the filter in the signal processing unit firstly, then are acquired by the DAQ card in the computer. Finally, the PD signals are identified by using ＂time-delay and pulse identification＂ anti-noise method. This system provides two-dimension and three-dimension analysis chart. Then, the differences in time domain and amplitude between the PD signal and pulse noise are analyzed in this paper, which prove the efficiency of the ＂pulse time-delay identification＂ anti-noise method. Since the first generator worked successfully, this monitoring system has been running stably for several months. Furthermore, it is easy to operate and the analysis result matches the pretesting data very well. This system meets the requirement of on-line monitoring.