Dynamic reactive compensation requirements at the rectifier end of an LCC HVDC link connected to a weak AC system

Abstract

Line commutated current source converter-based (LCC) HVDC systems are being considered for the transfer of power from remote wind resources to existing ac transmission systems. The rectifier terminals of these systems are connected to weak ac systems. A modified CIGRE HVDC benchmark model implemented in the PSCAD/EMTDC program is used to study the impact of varying amounts of dynamic reactive compensation on performance during rectifier operation. Determination of the amount of dynamic reactive compensation needed at the rectifier terminal is based on the following dynamic parameters: the magnitude of the first peak of the temporary overvoltages (TOVs) of the rectifier ac voltage following disturbance and time for the dc system to reach 80% of pre-disturbance dc power transfer after the clearing an ac fault. An effective short circuit ratio (ESCR) for best operation will be calculated based on the selected value of the dynamic reactive power compensation rating.