Effect of Ripple in DC on Voltage Endurance Coefficient of Cable Insulation Based on Damage Equalization Method

In the offshore transmission systems, the converters are used for AC to DC and DC to AC conversion. The utilization of HVDC cable transmission over AC transmission in offshore wind farms is quite efficient. On the DC side, the polymeric insulated cables are stressed by the DC voltage with huge amount of ripple content. The accelerated aging tests were performed to confirm the effect of the ripple voltage on the degradation of the cable insulation. The breakdown tests were performed on LDPE samples using ripple voltage with frequency of 500 Hz superimposed on DC voltage. This work investigates the effect of ripple voltage on the life of the offshore HVDC cable, that it is always important to consider interactions of all the system components while designing the cable insulation.