Investigation of PCB-based Inductive Sensors Orientation for Corona Partial Discharge Detection

This paper presents an experimental investigation of two different printed circuit board (PCB) inductive sensors, with meander and non-spiral shapes, to assess their capabilities and best orientation for corona partial discharge (PD) detection. First, simulations with the Ansys HFSS software are performed in order to evaluate the equivalent electrical circuit of the two sensors and their 2d radiation patterns. The meander sensors presented a resonant frequency of 600 MHz, while it was around 1.1 GHz for the non-spiral. The 2d radiation pattern showed that better sensitivity is achieved when the inductive sensor is oriented 90 degrees with respect to the PD source. Experimental tests showed a peak-to-peak voltage of the PD signal detected by both sensors of around 14 mV when the orientation was 90 degrees with a main frequency around 35 MHz. The peak-to-peak voltage dropped to about 5.4 mV and 6.9 mV for the meander and the non-spiral sensors, respectively, with a main frequency of about 33.5 MHz, when the orientation was 0 degrees. The obtained PRPD patterns and the PD signal shapes were quite similar to those provided by a HighFrequency Current Transformer (HFCT) commercial sensor.