Study of the effect of DCPR Stress on Space Charge Accumulation and Electric Field in LDPE

Apart from continued DC stress, DC-Polarity Reversal (DCPR) stresses are very common in HVDC systems. Space charge accumulation is of serious concern in HVDC systems, and can cause significant material degradation. This is further aggravated by polarity reversal. In this work, a computational model based on Bipolar Charge Transport (BCT) is developed to map the time dependent space charge and electric fields within LDPE insulation for constant DC stress, and validated with existing literature. The model is further extended to study the effect of DC-Polarity reversal. The effect of charge trapping frequency on the space charge distribution and the electric field enhancement during DCPR is analyzed. Trapping frequency is seen to significantly affect field enhancement.