Metal oxide varistor to limit dynamic overvoltages at the terminals of an HVDC converter

An investigation is reported of the technical and economic implications associated with using metal-oxide surge-arrester technology together with mechanically switched shunt capacitors to limit dynamic overvoltage (DOV) and provide reactive power at the inverter bus of a test system characterized by low short-circuit ratio. A conceptual design for a metal oxide varistor (MOV), that utilizes parallel metal-oxide surge-arrester columns in combination with a switching device and controls is proposed. Its cost, as well as that of the shunt capacitors, is estimated. It is demonstrated that a combination of MOV and shunt capacitors is an effective and potentially economical means of limiting DOV and providing reactive power compensation at the terminals of HVDC converters.>