Measurement-Based Characteristic Curves for Voltage Stability and Control at the Point of Interconnection of Wind Power Plants

In this paper, the measurement-based characteristic curves, reactive power-voltage ( Q-V) curve and reactive power-active power-voltage (Q-P-V) curve, are developed for voltage stability and control at the point of interconnection (POI) between a wind power plant (WPP) and a utility grid. The procedure to obtain an effective Q-V curve using the supervisory control and data acquisition (SCADA) measurement data is proposed. The SCADA data used in this paper were recorded in 2016 at the POI of a 27-MW WPP currently in operation in Newfoundland and Labrador (NL), Canada. Each Q-V curve is created for a particular month using the SCADA data corresponding to a very narrowly defined active power range, so the active power is considered constant as the conventional Q-V curve concept. The MATLAB curve fitting toolbox is used to realize the most fit mathematical equations for Q-V and Q-P-V curves. The developed Q-V and Q-P-V curves can be used for the data-driven voltage control for WPPs; and the Q-V curves can also be used for the voltage stability evaluation.