Partial Discharge Detection Of GIS Based On Pressure Balanced EFPI

As an important power equipment,gas insulated switchgear(GIS)is widely used in the process of power transmission and distribution,which is more and more related to the safe operation of power grid.Therefore,the detection of partial discharge of GIS to protect its safe operation plays an important role in ensuring the safe and stable operation of the power grid.Partial discharge will appear in the early stage of insulation deterioration of high-voltage electrical equipment,so the accurate detection of partial discharge in GIS can find its insulation defects in time and avoid serious power failure accidents caused by insulation breakdown.Using the ultrasonic signal generated by partial discharge to detect partial discharge can effectively avoid the electromagnetic interference on site and improve the sensitivity and accuracy of detection.However,at present,the piezoelectric ultrasonic sensor can only be attached to the outside of the cavity wall of GIS,the received ultrasonic signal will be greatly weakened due to the obstruction of the cavity wall,in addition,the interference caused by the ultrasonic signal propagating along the cavity wall will seriously affect the identification of partial discharge.In this paper,the pressure balanced extrinsic Fabry-Perot Interferometer(EFPI)sensor is built into the GIS cavity to detect the partial discharge.The working principle of the optical fiber EFPI sensor partial discharge detection system is introduced.The influence factors of the sensor sensitivity and natural frequency are analyzed.The appropriate fabrication parameters are determined according to the application environment of the sensor in GIS.The three-dimensional finite element simulation model of GIS cavity is established,and the simulation research on the detection characteristics of EFPI sensor in GIS is carried out.The experiment platform is built,and the sensor is used to detect the PD in GIS.The feasibility of the built-in EFPI sensor to detect PD in GIS is verified,which has a good detection effect.