A Review on the Condition Monitoring of HVDC Polymeric housed Surge Arresters

HVDC transmission has become increasingly necessary to connect renewable energy sources to the existing AC voltage grids. Recently several long distance HVDC transmissions are being executed and planned in the country, numerous converter stations have come up as a key link between the HVDC systems. Hence, there is a need for utmost protection for the converter stations. Composite or polymer housed ZnO surge arresters are being extensively used to protect the equipment to overcome various electrical stresses. There is no clear understanding of the aging of polymeric housed surge arrester used for the HVDC transmission system with scant information available. One important parameter proven to be highly challenging is the estimation/performance of the thermal behavior of polymeric arresters used in converter stations to withstand standard and non-standard surges encountered in the service. It is a known fact that voltage-current characteristics of zinc oxide varistors become degraded due to a series of stresses in service conditions. The present paper attempts a comprehensive review of degradation methods and the need for multi-stress aging studies on HVDC surge arresters. The paper highlights the current work initiated at our laboratory towards understanding more realistic and reliable assessment on aging/performance of surge arresters towards standard, nonstandard and complex waveshapes, along with the change in power flow and effect of voltage polarity reversal at the HVDC stations.