A partial discharge testing system based on a 5-level converter with different control signals

In this paper, analyses of a partial discharge (PD) testing systems using a voltage source from a 5-level converter with different control signals are presented. The low voltage source with 200 Hz of the test system is generated using the 5-level converter. The converter connected to a high voltage transformer, a partial discharge detection. The LC-filter type is set for the test system. The efficiency of voltage source from the 5-level converter with different control signal topologies, i.e. 5-level square wave, 5-level quasi-square wave, and 5-level sinusoidal pulse width modulation (SPWM) with modulation index (ma) of 1.0. The effect of the topologies to partial discharge test system is presented and compared in cases of the voltage difference, total harmonic distortion (THDv) of the output voltage, and the background noises in the partial discharge testing system with no-load and load test with a potential transformer (PT). It is found that the 5-level sinusoidal pulse width modulation (SPWM) with modulation index 1.0 provides the best performance in cases of the voltage difference and THDv of below 5%, and the background noise of below 2.5 pC.