Estimation of electric field and temperature in HVDC cables under different environmental conditions

Abstract

With the advent of transmitting power through the HVDC cable, polymeric insulation is gradually taking place over the mass impregnated and oil-impregnated paper because of its various benefits. Polymeric HVDC cables have excellent electrical and thermal properties, especially in design stress which is comparatively low with mass and oil-impregnated insulation. However, having these benefits and large studies, the study about the effect of transients such as polarity reversal for different load and ambient conditions are still not well addressed. To have a successful long-term life of the cable, better understanding the effect of the change in environmental temperature, especially for the soil, is needed. During transients, the insulation undergoes high electro-thermal stress, and with the inclusion of the change in soil temperature can even be more catastrophic. In this paper, the actual electro-thermal model of the cable was considered for simulation along with the non-linear DC conductivity was incorporated in this model for enhancing the exact performance of the cable. The transient condition was performed according to Cigré standard TB 496. The simulation was performed to obtain the change in electric field and temperature over this insulation in a wide range of environmental temperatures. The peak electric field has been analyzed.