Study of Space Charge Accumulation Property in Polyethylene under Applied Voltage of Square Wave

Space charge phenomena play an important role in dielectric breakdown, however, most studies focused on space charge accumulation characteristic under DC voltage while few studies about space charge under square voltage has been carried out. In this study, a new method for space charge measurement resorting to the Pulsed Electroacoustic (PEA) method under square wave voltage is presented. Using this method, we can measure the space charge distribution under square waveform of various waveform parameter (polarity, frequency, duty ratio, etc.) From the measurement result, we found that homo-charge is more likely to accumulate under square wave voltage, the space charge accumulation under unipolar square wave is much larger than that of bipolar square wave. And high frequency square wave will cause more serious charge accumulation. An increase in the duty cycle will also result in an increase in the amount of accumulated charge.