Preliminary Study on a Fiber Optic Extrinsic Fabry-Perot Interferometer Sensor of Acoustic Detection for Partial Discharge

Nowadays, the detection of acoustic emission (AE) signals of partial discharge (PD) is widely used for fault diagnosis of power equipments such as gas insulated substations and transformers in normal operation and factory tests. The sensors used for PD AE detection are usually based on the piezoelectric type (PZT) transducers, which only can be arranged on the shell of the power equipments with some disadvantages. In this paper, to develop a sensor used for PD AE detection with an embedded or built-in type, the fiber optic extrinsic Fabry-Perot interferometer (EFPI) sensor is investigated preliminarily. Focus is made on the design and experimental tests of the developed EFPI sensor. Results show that the developed EFPI sensor for PD AE detection is feasible and effective. At last, a method to design an integrated PD sensor with an embedded or built-in type is also introduced, which can detect UHF and AE signals of PD simultaneously to achieve the advantages of integrated use.