A Dual-Slot Barrier Sensor for Partial Discharge Detection in Gas-Insulated Equipment

This paper reports on the development and testing of a novel barrier sensor for UHF Partial Discharge (PD) detection in gas-insulated equipment. The sensor features a unique dual-slot planar antenna backed by an air-filled cavity. The dual-slot arrangement allows different parts of the antenna to resonate at different frequency ranges in the UHF spectrum. As a result, the sensor exhibits broader bandwidth and higher sensitivity than other barrier sensors. Finite Element Analysis simulations have been used to optimize the sensor design. Furthermore, testing using a specially made PD test rig, GTEM cell testing and testing on a gas-insulated line section in the high voltage laboratory, have validated the simulation results and the capabilities of the sensor. The Dual-Slot Barrier (DSB) sensor exhibits a bandwidth of 0.3 - 2.0 GHz with a mean effective height of 13 mm, and an effective height above 2 mm for 90% of the frequency range. The sensor can be used with both wideband instruments, such as oscilloscopes, and narrow band instruments such as frequency downconverters. Additionally, its optimized dimensions and unique replaceable sealing attachment ensure maximum compatibility for retrofitting on a wide range of equipment.