Verification of the applicability of an RF-signal-based detection method for partial discharges on inverter-fed random wound stator windings in a low-voltage induction motor

Partial discharges (PD) are widely known to occur in medium- and high-voltage applications. Recently, it has been observed that owing to the use of modern variable frequency converters, an environment that contributes to partial discharges is also found in low-voltage motors. Low-voltage machines are vulnerable to partial discharges because their winding insulation is not designed to withstand the phenomenon. As the number of inverter-driven systems is growing, the PD become a critical reliability issue. Therefore, methods to measure the phenomenon are required for the purposes of product development and maintenance. In this paper, detection of partial discharges in random wound low-voltage induction motors is studied by applying a radio-frequency-signal-based measurement setup for online partial discharge measurements.