Phasor model simulation of a grid integrated variable speed pumped storage system

Abstract

This study presents a phasor model simulation of a grid integrated variable speed pumped storage (VSPS) system focusing on generating mode. The VSPS is configured by the voltage sourced converter doubly-fed induction machine (DFIM) scheme. A wound rotor induction machine dynamic mathematical model and generalised averaging theory are adopted to derive the phasor model technique of the system. Based on the dq -axis synchronous reference frame concept, the direct power control strategy of the system is designed. The steady-state and transient stability responses of the proposed system are analysed in MATLAB/Simulink platform by considering a 300 MW/18 kV/50 Hz DFIM-based VSPS system and a grid consisting of two hydropower plants with synchronous generator, a diesel power plant with synchronous generator, a solar photovoltaic farm and fixed loads. A comparison of phasor model and detailed model simulations of the system is also conducted. The results show that the grid integrated VSPS system is stable without significant deviation in grid voltages, DC voltage and rotor speed of the DFIM unit under the designed control strategy. Moreover, the phasor model simulation achieves results with good accuracy as the detailed model, but with faster speed. Hence, the phasor model simulation is very effective for analysis and control design of large grid integrated VSPS systems.