Influence of Electromagnetic Sensor Location on Repetitive Partial Discharge Inception Voltage in Actual Stator Core of Inverter Fed Motor

Repetitive partial discharge inception voltage (RPDIV) measurement is indispensable for inverter-fed motor when testing the insulation dignity according to IEC 60034-18-41 IS. Our previous study showed detection sensitivity comparison among kinds of electromagnetic (EM) sensors for PD measurement in an actual motor core. This paper deals with an influence of the location of EM sensors on the sensitivity of detected EM wave to quantitatively evaluate RPDIV. As a result, it was found that employing the EM wave sensor located at the furthest position from the PD source on Z axis to detect PD can result in estimating higher RPDIV by 7.5 % at most than an actual one, depending on the sensor location. The possibility of location of a PD source using multiple LSs placed in the actual core is also suggested from differences in the signal strength and time for EM signal to reach multiple LSs.