Research on the Low Voltage Fault of Doubly-fed Variable Speed Pumped Storage

This paper focuses on the low voltage ride-through (LVRT) technology and related control issues for pumped storage. Aiming at the existing control methods deficiencies of auxiliary hardware circuit and improving control strategy for gird faults, a mode switching control method based on the depth of the grid voltage drop is proposed, where an inductance emulating control(IEC) method that optimized in the EMF compensation term and PI controller is used within the 80% drop depth range, a double impedance substitution control(DISC) is enabled when the range being exceeded. The grid side converter (GSC) and rotor side converter(RSC) are connected in parallel and both are equivalent to inductive impedance. The simulation experimental model has been established, the energy flow of the system is analyzed under different working modes. The proposed method has been compared and analyzed with demagnetization control method (Method-l) and stator current feedback control method (Method-2), from the dimensions of DC-bus voltage, the voltage and current of RSC, and electromagnetic torque stability. The experimental results demonstrate the effectiveness and applicability of the strategy.