Simulation On Dynamic Space Charge Behaviour In LDPE

HVDC cable with low-cost, low losses and without reactive power losses, ismostly used to transport electrical power over long distances, therefore, HVDCCable has become an important research topic in recent years. However, there aresome key technical issues in the research of HVDC power cables account for itsspecial characteristics. Due to the Joule heat caused by the current in the HVDCcable conductor, the temperature gradient is appearance in the insulation, whichcould lead to the gradient of conductivity and influence the distribution ofelectrical field and space charge. So the research for the space charge and electricfield distributions of polyethylene under HVDC stress and temperature gradienthas a high theory and engineering values.Moreover, the charge distribution gotten by PWP and PEA is thedistribution of net space charge in LDPE, which could not factually reflect thesource and transport process of space charge in film. In this paper, a numericalmodel to describe the process of space charge transport in Low DensityPolyethylene (LDPE) is established, which includes injection, trapping andrecombination. Based on the numerical model, the space charge behaviours inLDPE under different temperatures and different temperatures gradient arestudied.The results show that the space charge distributions and the distortedelectric field are closely related to the temperature in LDPE. Moreover under thesame time, the increase of temperature difference leads to the increase of theelectric field near the anode and the decrease of the electric field near the cathode.