Experiment and Simulation of Space Charge Distribution in 35mm Cable Insulation

In this paper, the space charge behavior in 35mm cable insulation was studied. Space charge profiles of a cross-linked polyethylene (XLPE) cable were obtained through a full-scale measurement system based on the pulsed electroacoustic (PEA) method. The high voltage pulse was coupled to the measurement area through the contiguous insulation. Due to the attenuation and dispersion, the acoustic signal generated by the pulse near the copper core was significantly affected during the propagation to the sensor. Limited by the dc voltage source, the applied electric field is relatively low. Thus, a one-dimensional bipolar charge transport model was developed to study the space charge characteristic under high dc stress. The model was optimized for the coaxial cable on the aspect of cylindrical geometry under dc stress. Poisson's equation, continuity equation and transport equation were solved, with injection and extraction, trapping and detrapping, and recombination taken into account. By comparing the space charge profiles obtained respectively from experiment and simulation, the accuracy of the simulation is verified.