Wideband Omnidirectional Ultra High-Frequency Sensors for Detection of Partial Discharge Sources in Air-Insulated Electrical Substations

Partial discharges are critical indicators of insulation defects, which, if undetected, can lead to equipment failure and power outages. Presently, UHF-based PD monitoring system are gaining the interest of researchers. However, the UHF band contains various communication and broadcasting frequencies, such as those utilized by cell phones and Wi-Fi. Moreover, the emission of the UHF signal from any PD is also a broadband phenomenon, and can have a wide variation in central frequency, which mostly varies due to the type of defect, insulation type, voltage level, and weather conditions. Earlier various researchers focused on the design of broadband UHF sensors, but monitoring air-insulated substations with a wideband band of high gain could be more effective. In the work, a wideband omnidirectional UHF conical PD sensor has been developed. The omnidirectional feature enhances the detection capabilities in all directions, ensuring PD signals are captured around the installed sensor in an air-insulated electrical substation. In the paper, details of the optimized designed sensor, and its performance parameters, are presented. The developed sensor was found to be suitable for use in Air-insulated Electrical substations and also for the monitoring of high-voltage transmission towers.