PD Pattern Analysis Relevant to PWM-like Voltage Waveforms

- Low voltage rotating electrical machines are usually characterized by organic enameled wires windings that can not be subjected to the Partial Discharge (PD) activity since it acts an organic material erosion until the total failure of the electrical equipment. Moreover, to have a good control of the speed and torque of the electric motor, usually they are fed by power electronic drives that generates voltage waveforms with lots of harmonic distortion and fast rise and fall times such as PWM power supply. With sinusoidal voltage waveforms, the PD measure can give useful information about the defect of the device under test. It can be interesting to investigate if it is possible to analyze the PD pattern shape even when the voltage waveform power supply has fast rise and fall time fronts. The purpose of this research work is to acquire the PD pattern with an ad hoc measurement system to study the shape of these graphs even when in the case of fast rise and fall time fronts.