New tools to determine the partial discharges of inverter fed motor

With the development of AC drive and power electronic elements, inverter supplies apply to traction motors widely. At the same time, inverter mechanism brings on premature insulation aging in numbers of inverter fed motors all over the world. Insulation aging seems to be correlated with the partial discharges (PD) activity of surges with very fast rise time and high frequency. With the traditional method, it is hard to distinguish the PD signals from the surges. This paper introduces a new instrument, which can accurately measure the characteristics of PD during 100 ns rise time surges. In addition, it can also be used to measure the partial discharge inception voltage (PDIV) and other characteristics of PD in inverter fed motors under local surge conditions.