Design, Optimization and Experiment Study of Internal UHF Sensor for Partial Discharge Detection in GIS

For the detection of partial discharge (PD) in gas insulated switchgear (GIS) that based on ultra high frequency (UHF) method, UHF sensor is the core part of the detecting system and it plays a crucial role to the detecting frequency band, sensitivity and accuracy Therefore, the design, practical optimization and actual test of the sensor was studied in this paper. Firstly, the key parameters and design requirement were analyzed and a reasonable design scheme was proposed. Secondly, the design and optimization of the sensor body and impedance transformer were separately discussed. On this basis, the sensor model was made according to the previous scheme. Then multiple tests of the parameter and performance were conducted. The results indicate that the band width is from 700MHz to more than 3GHz, which meet the requirements of the parameters. And the sensor has good receiving performance to the PD signal, while the output of sensor can reflect the occurrence of PD as well as the feature of defect. The design scheme has also been proved to be reasonable. Finally, the receiving test of actual PD signal inside GIS was executed, which verified that the designed internal UHF sensor has good receiving performance in the actual detecting environment and the application requirement is satisfied as well.