The Effect of AC Ripple Voltage on Space Charge Accumulation in Double Layer Polymer Samples

High frequency AC ripple voltage due to the switching of the converter's power electronic valves is an undesirable artefact in high voltage direct current (HVDC) transmission. This paper presents an investigation of the effect of AC ripple voltage superimposed on the DC voltage on space charge accumulation and electric field profiles in double layer polymer samples. A pulsed electro acoustic method (PEA) was used to measure the space charge accumulation under pure DC voltage and under 10% AC ripple voltage superimposed on DC voltage. The experimental results demonstrate for the first time that the presence of ripple voltage enhances the accumulation of homocharge close to the electrodes as well as charge at the interface between the two layers.