Rapid Power Compensation-based PV Generation System Damping Electromechanical Oscillation

By modulating the active power output of the grid-tied inverter, the photovoltaic (PV) generation system can effectively damp the electromechanical oscillation of the power grid. To analyze the influence of different PD controller gains on its output power for the typical droop and inertia control strategies, this paper takes the conventional application scenarios of PV damping electromechanical oscillation as the research example. Studies show that when the PD controller gain is amplified to the limit condition, the PV generation system will operate in the rapid power compensation (RPC) mode: based on the speed deviation polarity, the active power modulation limit (Pmppt or 0) will be used as the basis for alternate output to damp the system imbalanced power. The comparison of speed indicators shows that the RPC mode is significantly stronger than the conventional droop and inertia control for grid electromechanical oscillation damping. In view of this, this paper proposes a novel grid electromechanical oscillation damping strategy based on RPC mode, and sets the switching thresholds and corresponding active current commands for 4 operating conditions to quickly and effectively suppress the generator rotor speed oscillation phenomenon. The simulation results show that the proposed control strategy in this paper does not require a complicated control parameter tuning process, and can significantly suppress the system electromechanical oscillation, which is beneficial to ensure the power system stable operation.