A Novel UHF Partial Discharge Sensor Based on the Secondary Terminal Box of a Bushing Current Transformer

Abstract

To address the difficult installation and maintenance of built-in ultra-high-frequency (UHF) sensors and the susceptibility of external sensors to electromagnetic interference, a non-intrusive partial discharge (PD) sensor based on the secondary terminal box of a bushing current transformer is proposed. A sensor model is established in CST, and the effects of the metal disc radius, dielectric plate dimensions, and relative permittivity on the effective height are analyzed. The optimized sensor is then verified using a GTEM cell and a transformer simulated PD test platform. The results show that the measured average effective height of the optimized sensor reaches 10.64 mm in the frequency range of 300～1500 MHz. The sensor can effectively detect internal PD signals in transformers while providing convenient installation and good anti-interference performance.