Space Charge Measurement of 23-mm-Thick XLPE Cable at Ambient and High Temperatures

Space charge measurement was performed on a 23-mm-thick cross-linked polyethylene (XLPE) cable at ambient and high temperatures using a newly developed high-sensitivity measurement device and a correction method for cables under temperature gradient. The space charge and electric field distribution were obtained with a spatial resolution of 0.5 mm (2%) at ambient and high temperatures. In addition, we propose an approach to obtain the
in situ
system’s impulse responses to maintain correction accuracy for long-term measurement. The reference waveforms were measured before and after 3 h of testing voltage application. It showed that sufficient time before the measurement is necessary for accurate reference waveforms. To obtain a suitable time for the measurement, the method using cross correlation was proposed.