Abstract

Partial discharges (PDs) are critical early indicators of insulation degradation in high-voltage (HV) equipment. Reliable detection of PDs is essential to avoid catastrophic failures in power systems. Conventional narrowband antenna systems used for PD detection often suffer from poor sensitivity, limited frequency response, and are unable to detect weak transient signals over a broad spectrum. This work proposes a novel ultra-wideband (UWB) spiral monopole antenna tailored for enhanced sensitivity in PD detection. The design focuses on achieving a broadband response from 300 MHz to 3 GHz, allowing efficient capture of high-frequency transient PD signals. The antenna is fabricated using FR-4 substrate and validated through both simulation (using CST Microwave Studio) and experimental testing on a HV test platform with artificial PD sources. The system achieved over 90% PD detection accuracy across multiple insulation materials, outperforming conventional whip and dipole antennas in signal-to-noise ratio (SNR), bandwidth, and detection range. Results demonstrate the antenna’s high directivity, gain uniformity, and excellent transient response.