Simulation Analysis of AC Withstand Voltage Test Method for GIS Based on Same-frequency Same-phase Principle

The newly-built GIS and the original part are isolated only by the bus bar isolating switch. If the conventional frequency-modulated series resonance voltage withstand test method is used in the AC voltage withstand test of the newly-built GIS while the original part is charged, there must exists a moment at which the testing voltage and the running voltage overlaps to make the break voltage get maximum， resulting the isolating switch breakdown and GIS equipment in danger. To solve the problem, Based on the analysis of the fracture voltage of the isolating switch during the electrification test, a field AC withstand voltage test method based on the principle of the same frequency and same phase is proposed, and the simulation model is further improved. The voltage and current surges of various parts in the GIS are analyzed. Based on the simulation, it is proposed to reduce the voltage and current surge by changing the resistance in the loop. Based on the principle of the same-frequency phase-in-phase AC withstand voltage test method, it is possible to carry out the AC withstand voltage test in the expansion part, improve the reliability of power supply, and have very significant economic and social benefits.