Investigating space charge dynamics in polymers by the improved pulsed electro-acoustic method

For decades, the space charge effect and the distortion to the electrical field have been considered as the most important secondary effects on electric treeing, aging and breakdown phenomena in polymers. Several space charge distribution measuring techniques have been developed and applied to clarify the charge dynamics, i.e. charge injection, accumulation and transportation characteristics. This paper shows our experimental results of space charge dynamic behaviors inside the sheets of LDPE, Thin/Thick HDPE, and UHMWPE under dc voltage applications. The space charge distributions are obtained by using the newly proposed simulation model to process the detected pulsed electro-acoustic signals. Comparing to the old signal processing procedures, the accuracy is improved especially at the electrode-sample interface. The resolution has found to be greatly improved too