Research on Dynamic Breakdown Characteristics of Bus-Charging Current Switching Test on Disconnector

The bus-charging current switching test duty 1 is an important test to assess the dynamic insulation performance of isolating distance for the GIS disconnector. When the design of the fixed and moving contacts of the GIS disconnector is unreasonable, it may directly cause the disconnector breakdown to earth during the closing and opening operation. This article relies on the ultra-high voltage fault diagnosis analysis and test task of State Grid Corporation of China, six 1100 kV GIS disconnectors are used as the research object to conduct the bus-charging current switching test on disconnector, a broadband transient voltage to earth waveform acquisition system and arc optical monitoring system are constructed, and the measurement results are excellent. The research shows that the closing resistor has a good effect on limiting the overvoltage during the test duty 1; the increase of the inflation pressure helps to reduce the prestrike gap distance; improving the movement speed of the disconnector contacts helps to reduce the overvoltage amplitude; the initial electric field distribution between the moving and fixed contacts will have a significant impact on the subsequent arc development process. This study can provide guidance for customers on the internal insulation coordination of GIS disconnector and improvement of insulation structure design.