A novel embedded sensor for partial discharge detection in inverter-fed machines

This paper presents a novel ring-shaped hybrid fractal antenna for detection of partial discharge (PD) in inverter-fed machines. Partial discharge is known as a source of degradation and lifetime reduction in the machines winding insulation. PD activity is becoming a major concern in high performance drives, especially due to the increased use of repetitive impulse voltage with short rise-time (high dv/dt) from PWM-controlled inverters. The proposed hybrid fractal antenna is designed and experimentally demonstrated to show a high sensitivity in the ultra-high frequency (UHF) bandwidth of interest for PD detection as well as an ability to discriminate PD signals from other sources of high frequency disturbances. Additionally, the proposed PD sensing solution features a unique ring-shape geometry which facilitates its physical integration to a live machine, making it suitable as a non-invasive solution for online condition monitoring and PD detection of any inverter-fed electrical machine.