Development of a High-Resolution Space Charge Measurement Device Using the PEA Method

At high electric fields, the injection, migration and accumulation of charge in the internal space of the insulation can cause electric field distortion, thus increasing the probability of insulation failure. When insulation materials work with increasing electric field strength, the way to study the space charge distribution under a high field is to reduce the insulation thickness. The conventional pulsed electro-acoustic (PEA) method with the measurement resolution of about 10 20 ns half-peak width of space charge signals is no longer sufficient for specific cases where the insulation is quite thin. In this paper, a modified PEA system was realized by developing an ultranarrow electrical pulse generator based on the Marx-type circuit. To verify the resolution of the modified system, the raw space charge signal of cross-linked polyimide (PI) was acquired and compared to the original experimental result.