Coordinated Voltage Control Scheme of an Adjustable-Speed Pumped Storage Hydropower and a Wind Power Plant

As a type of inverter-based generation, an adjustable-speed pumped storage hydropower (AS-PSH) plant is a functional extension of conventional PSH plants and can provide more flexible and faster responses to provide ancillary services than conventional synchronous generators, thereby making a positive impact on power system voltage stability. This paper proposes a coordinated voltage control scheme of an AS-PSH plant with a wind power plant (WPP). The coordinated controller dispatches partial voltage set points, which are determined in proportion to the reactive current capability of each unit; thus, the controller enables the unit with a larger capability to receive a larger voltage set point so that the coordinating controller enhances the voltage controllability of the units. In addition, to stabilize the voltage at the point of interconnection after a fault clearance, reactive current initialization schemes are implemented in the AS-PSH and WPP controllers. The initialization schemes detect a sudden voltage rise (indicating the fault clearance) and enable the AS-PSH and WPP to rapidly reduce reactive current injections to the power system. The performance of the proposed scheme was tested for small and large voltage dips using PSCAD.