Simulation and Actual Measurement and Analysis of Electromagnetic Interference Generated by GIS Switching Operation

Very fast transient overvoltage (VFTO) generated during gas insulated switchgear (GIS) switching operation. On the one hand, it couples with the GIS casing to generate transient enclosure voltage (TEV), the transient enclosure voltage flows into the grounding grid and causes transient ground potential rise (TGPR). On the other hand, it generates a transient electromagnetic environment externally, resulting in spatial electromagnetic interference. The high-amplitude, wide-bandwidth, and fast-front electromagnetic transient phenomena pose significant threats to the safe and stable operation of secondary equipment. This paper measures the TGPR and spatial electric field generated by GIS switches in converter stations and studies the waveform characteristics and distribution patterns of TGPR and spatial electric fields through three-dimensional electromagnetic simulations. The simulations align well with actual field measurements in terms of amplitude, duration, frequency spectrum, and other parameters, validating the accuracy of full-wave simulation calculations. The study found that GIS switching operations can cause ground grid potential rises of several kV and simultaneously radiate spatial electric fields of tens of kV/m, with very short pulse durations.