Partial discharges measurement during under-damped steep-fronted overvoltages

J. M. Martínez-Tarifa and G. Robles, “Partial discharges measurement during under-damped steep-fronted overvoltages,” 2020 IEEE International Instrumentation and Measurement Technology Conference (I2MTC), Dubrovnik, Croatia, 2020, pp. 1-5, doi: 10.1109/I2MTC43012.2020.9129294.

Abstract – Inverter-fed drives have become essential in most industrial processes nowadays to control the speed of rotation of electric motors. Unfortunately, the insulation of these electric motors show unexpected failures due to the appearance of partial discharges (PD). These type of discharges undermine the insulation along time creating weak spots than can cause total breakdowns. Thus, the detection of partial discharges is a challenge that must be faced by electric motor manufacturers and users. The problem of detection is intensified because the voltage supplied to the motors is based on steep-fronted pulses and PD are also very narrow pulses so it is quite complex to separate them from the electrical interferences created by the train of square pulses. In this paper, two different radio- frequency (RF) sensors will be used to detect PD in an insulation system subjected to square voltages with low rise-times. The response will be analyzed in the UHF range to select the best option for the detection of those hazardous under-damped pulses.