Experimental Study on Electromagnetic Transient Interference Characteristics in the Secondary Side of UHV Fixed Series Capacitors

In isolating disconnect switch of Ultra-high Voltage (UHV) Fixed Series Capacitors (FSC), electromagnetic interference (EMI) problems arises on the secondary-side protection and control devices. This paper focuses on high-potential measurement and characterization of EMI in the secondary side of UHV Fixed Series Capacitors. An experimental platform has full size with in-service projects was built at first, and corresponding high-potential platform-based measurement system was setup. Then, by isolating the disconnect switch in the experimental circuit, the common-mode voltage, differential-mode voltage and current in both cases with CT cable shields grounded at CT side and at control box side were obtained. In addition, EMI characterization was described and analyzed, and statistical distribution was given. Lastly, several proposals based on EMI data and characterization were presented to shed light on design and engineer of UHV Fixed Series Capacitors in addressing EMI problems.