Remote Sensing of Partial Discharge in Gas-insulated Switchgear (GIS) Using a 3 × 3 Optical Interferometer

Abstract

Gas-insulated switchgear (GIS) is a kind of electric switch widely used in high-voltage applications where partial discharge (PD) frequently occurs, leading to degradation of the equipment. In this study, we present a novel method for detecting the PD occurring in a GIS chamber by using a 3 × 3 optical interferometer. The proposed system can remotely measure sub-nanometer displacements, enabling the detection of PD-induced surface vibration or displacement on the GIS housing. The correlation between PD intensity and the induced surface displacement was analyzed experimentally. The results showed that as PD intensity increased, the spectral components of the displacement signal were intensified within a 1–5.5 kHz range. After band-pass filtering there, it was observed that the displacement amplitude increased proportionally with PD intensity. The proposed method is expected to offer a remote and realtime alternative for GIS condition monitoring and increase operator safety and system reliability.