Measurement and Analysis of the Switching Transients in 500 kV Pumped Storage Power Plants

Pumped storage power plants (PSPPs) are among the most efficient and practical large-scale energy storage systems. In recent years, several transformer failures have occurred in PSPPs, and transient overvoltage is considered a potential reason for failure. However, there is a lack of field measurement results for transient analysis. In this paper, a switching transient measurement system and multipoint synchronous triggering system were developed. Field measurements were carried out in three PSPPs. According to the measurement results, the maximum amplitude of the switching overvoltage was 630.6±46.5 kV. The shortest front time was 76±7.6 ns. The largest steepness was 1130±140.8 kV/μs. A simulation model was built to analyze three phenomena in the transient, including multistep waveform, overvoltage peak, and power transformer demagnetization. The measurement and analysis results are beneficial for the improvement of simulation modeling. It is helpful to pinpoint potentially damaging transients for equipment manufacturers and designers of PSPPs.