An Ultra-Wide Band Multi-Layered Hatch-Mounted UHF Partial Discharge Sensor for High-Voltage Power Transformers

Monitoring of partial discharges (PD) activities within high-voltage power transformers are necessary for assessing insulation health conditions and early prediction of insulation failures. Hatch-mounted UHF PD sensors are used for non-contact monitoring of PD activities within power transformers on a continuous basis. The design of the UHF PD sensors is intended to capture electromagnetic waves emitted from the PD sources in the UHF frequency band (300–3000 MHz). Conventional hatch-mounted UHF PD sensors are mechanically robust but lag in sensitivity for their limited bandwidth. This paper presents a multi-layered UHF PD sensor design compatible with mounting over the inspection hatch windows of the high-voltage power transformers. The proposed design offers an ultra-wide bandwidth of 2572 MHz (95.26% of the UHF band) and an operating frequency range of 303 MHz to 3000 MHz.