Optimizing small antenna configurations for partial discharge monitoring of electrical assets

As power networks transition towards a predominant low carbon future with changing load and generation profiles, effective power network asset management is increasingly essential, encompassing challenges such as aging infrastructure, investment in sustainable assets, and a shift from reactive to predictive maintenance. Predictive maintenance relies on complete, accurate, and timely data from network assets. Partial discharge (PD) activity can degrade the insulation of network assets, posing a significant threat to network reliability and security. However, these discharge events also serve as prognostic and diagnostic indicator in that they emit radio frequency range electromagnetic signals, which can be detected and analyzed to assess asset health. Often PD is detected using small broadband antennas “matched” to the instrument input impedance. The accuracy of detecting these signals depends on the physical size and the reception capability of antennas, commonly represented by the standing wave ratio (SWR). Therefore, it is important to optimize antenna performance to ensure data quality. This study characterizes various small broadband antenna arrangements based on their SWR responses, investigating multiple combinations of small antenna arrangements. The aim is to identify small footprint configurations with higher reception capability for PD detection to enhance measurement sensitivity and thus signal accuracy. Results presented demonstrate that using a combination of single antennas appropriately configured and connected to a PD instrument can improve signal reception compared to the industry-standard practice of using a single antenna on a handheld PD device. The improvement is demonstrated practically through comparison calculations of PD signal energies over frequency bands of interest.