Research on Multiband Interference Suppression Log Periodic Antennas for Partial Discharge Detection

The complex electromagnetic environment inside the substation can greatly affect the accurate detection of partial discharge (PD) signals. Band-reject frequency filters may be attached to the antenna, often at the detriment of the insertion loss. A novel log-periodic dipole array (LPDA) for ultrahigh-frequency (UHF) PD detection in substations is proposed, featuring multiband interference suppression capabilities. Based on a conventional LPDA model, an enhanced design covering 0.3-3 GHz is developed using ANSYS HFSS simulation software. The antenna is engineered to suppress interference from communication signals (0.79–0.96 GHz) and wireless transmission sources such as Wi-Fi and Bluetooth (2.4-2.5 GHz) through hardware-level optimization, with the voltage standing wave ratio (VSWR) in these rejection bands exceeding 40. To address the issue of over-suppression commonly encountered in high-frequency narrowband interference mitigation, a dynamic scaling factor adjustment method is introduced. Furthermore, a multiscaling-factor strategy is investigated to achieve frequency-specific gain control across multiple target bands, which elevates gain in the reconfigured band from 7 to 9 dBi. A general design framework for developing LPDA with “multiband, multigain, and interference-resilient” characteristics is proposed. Experimental validation is conducted with a focus on suppressing communication band interference, demonstrating 20 dB suppression against communication interference signals.