GIS隔离开关方式1试验中断口对地击穿时光电暂态过程监测与分析

Monitoring and Analysis of Optical and Electric Transient Process Induced by Breakdown-to-ground During Type Test Duty 1 of GIS Disconnector

开合短母线(方式1)试验是考核GIS隔离开关断口动态电气性能的重要试验。由于动静触头结构设计不合理,将直接导致GIS隔离开关在分合闸时,在断口处发生对地击穿。文中为确定GIS隔离开关试品在方式1试验中发生对地击穿的有效判据,构建了光电暂态全过程监测系统,包括GIS超宽频VFTO和外壳暂态地电位测试系统,以及高性能高速摄像机。GIS隔离开关方式1合闸过程中断口发生对地击穿时,文中采用高速摄像机同时记录下断口击穿电弧和动触头对地击穿电弧的形态,直接证实试品发生了对地击穿。通过隔离开关正常和异常合闸过程中电压监测数据的对比分析,发现GIS隔离开关合闸发生对地击穿时,AC侧电压的测试值跌落至0 kV,而后又恢复至试验电压,DC侧电压测试值跌落0 kV。而且导致合闸过程中前两次预击穿间隔时间从数十ms增大至200 ms以上,断口对地击穿造成的电压跌落时间约100 ns。此外发现当隔离开关合闸发生对地击穿时,GIS外壳暂态电位信号将在2 ms内将出现瞬时频率更高的新分量,持续近1 ms。通过文中的试验研究,形成了隔离开关方式1试验中试品发生对地击穿的有效判据,有助于GIS隔离开关的性能考核。

Switching of short busbar(duty 1)is an important test to evaluate the dynamic electrical performance ofopen contacts of GIS disconnector. Unreasonable design of the moving and stationary contacts structure will,in caseof opening and closing operation of GIS disconnector,directly lead to the breakdown to the ground at the open con-tacts. In order to determine the effective criterion of the breakdown to the ground in test duty 1 of GIS disconnector,an optical and electric transient process monitoring system,including GIS ultra-wide frequency VFTO and enclosuretransient potential measuring system as well as high-performance high-speed camera,is constructed. In case ofbreakdown to the ground at the open contacts during the closing process of test duty 1 of GIS disconnector,the high-speed camera is used to record the configuration of breakdown arc of the open contacts and breakdown arc of the mov-ing contact to ground simultaneously,which directly confirms the breakdown of the prototype to the ground.Throughthe comparative analysis of voltage monitoring data during normal and abnormal closing operation of GIS disconnector,it is found that when the breakdown to the ground occurs in the closing operation of GIS disconnector,the measur-ing voltage value at AC side drops to 0 kV,and then recovers to the test voltage. While,the measuring voltage valueat DC side drops to 0 kV.The time interval of the first two pre-arcing is increased from tens of ms to more than 200 msduring the closing operation.The voltage drop time caused by the breakdown of open contacts to ground is about100 ns. In addition,it is found that,in case of breakdown to the ground in the closing operation of disconnector,thenew component with higher instantaneous frequency will appear in transient potential signal of the GIS enclosurewithin 2 ms with duration of nearly 1 ms. Through the experimental research in this paper,the effective criterion ofground breakdown to ground of test duty 1 of GIS disconnector is formed,which is helpful to the performance evalua-tion of GIS disconnector.