A High-Sensitivity Partial Discharge Detection System Based on a Superwide-Band Reconfigurable Antenna Sensor for Insulation Diagnosis in IIoT Applications

Accurate partial discharge (PD) detection and insulation diagnosis are essential for ensuring the operational safety of high-voltage (HV) power equipment, while wideband high sensitivity PD detection is extremely imperative since most of the PD events reflecting potential insulation defects have low strength (<1 pC) with wideband features. However, conventional wideband detection methods such as high-frequency (HF) antennas often suffer from the trade-off between low sensitivity, increased noise and the bandwidth requirements due to their low-Q features in the wideband sensing, and the vulnerability to in-band narrowband interference, especially in complex industrial environments. To address these challenges, this paper proposes a novel high sensitivity super-wideband PD detection system for Industrial Internet of Things (IIoT) applications integrating a reconfigurable high-frequency antenna sensor (RHAS), a bandwidth-reconfigurable low-noise amplifier (BRLNA), and a sub-band synthesis algorithm with built-in narrowband interference rejection (NIR) function. The RHAS captures weak PD signals across 48 high-Q sub-bands, which are individually amplified and digitally synthesized to reconstruct the wideband signal with enhanced sensitivity. The proposed system enables remote, clamp-free PD detection with strong NIR capability near grounded conductors, significantly outperforming the traditional sensors such as High-Frequency Current Transformers (HFCTs). Experimental results demonstrate a detection bandwidth from 1.4 MHz to 98.2 MHz (194.38% relative bandwidth) and a minimum detectable PD level of 0.3 pC. Compared with HFCT based systems, the proposed method achieves a 0.4–4.2 dB improvement in PD signal-to-noise ratio (SNR) and a 6.1–8.4 dB increase in total system gain. These results validate the effectiveness and robustness of the proposed approach for high-sensitivity wideband PD monitoring.