Space charge distribution measurement in liquid dielectrics subjected to impulsive high voltage based on time-continuous kerr electro-optic field mapping measurement

Abstract

The electric field and space charge distribution in the propylene carbonate subjected to switching impulse voltages is measured by array photodetector in this paper. With the use of array photodetector, we can detect light intensity variations over time at several positions between the electrodes under a single impulse voltage, which brings us the electric field and space charge distribution at any time under a single impulse voltage. The relative error can be guaranteed below 2.5% when the mean electric field across the gap E>3.5kV/mm. This measurement can be used in continuing research of space charge effects with other liquid dielectrics and can help us to deeply understand the breakdown mechanism of liquid dielectrics affected by space charge. The results indicate that bipolar homo-charge injection occurs under this condition. Meanwhile, owing to the advantages of high spatial and temporal resolution of array photodetector, we found that the injection of positive charges and negative charges have differences on both quantity and time. The main reason for this phenomenon could be the generation of positive and negative charge are non-simultaneous.