Printed-Board Inductive Loop Topologies Performance for Partial Discharges Detection

Partial discharges (PD) are localized breakdowns in the insulation within high-voltage (HV) equipment and can be a warning sign of potential future failure. Regular PD monitoring through preventive maintenance is essential to the reliability of many expensive HV apparatuses. Hence, the purpose of this work is to assess the performance of a novel class of multi-turn inductive loop sensors based on printed circuit board (PCB) to detect PD in free space. Based on their topology, three distinct inductive sensors, named meander, non-spiral, and spiral, are evaluated towards detecting in-lab corona, internal, and surface PDs. Through simulations and measurements, the low-frequency lumped-element circuit model for each of the three magnetic field probes was extracted. Experimental PRPD patterns showed that the three evaluated inductive loops could be effectively applied for online monitoring and recognition of PDs. The experimental results show that the single PD pulses detected by the three sensors have a typical PD pulse shape that is a damped sinusoidal function with frequency spectra spanning from 14.84
 
MHz to 46
 
MHz. The spiral sensor yielded the maximum sensitivity, while the meander topology produced the lowest.