Fiber Fabry-Perot sensor for partial discharges detection

Abstract

Partial discharge (PD) is an early warning for deterioration of oil-paper insulated equipment, which seriously endangers the safety of power system. It is significant to realize online detection of PD in oil-paper insulated equipment. Due to the advantages of anti-electromagnetic interference and locating the discharge source, the acoustic emission (AE) method is widely used in online PD detection. Conventional piezoelectric transducer (PZT) acoustic sensors cannot be installed inside equipment in practical applications, resulting in low sensitivity and susceptibility to electromagnetic interference from electrical equipment. To solve the above issues, an ultrasonic sensor based on Fabry-Perot (FP) interferometer with gold-coated circular fused silica diaphragm is proposed and experimentally verified. The results show that the fiber optic ultrasonic sensor can be placed inside the oil-paper insulated equipment for partial discharge detection, and has higher sensitivity compared with the traditional PZT.