Damping Injection Control Strategy of Low Frequency Oscillation in Photovoltaic Power Plant

In this paper, an active power/voltage combined damping injection control strategy for photovoltaic power plants is proposed, and its suppression effect on low frequency oscillation of power system is analyzed. In order to study the suppression effect of this control strategy on low-frequency oscillation of the system, a small-signal model of photovoltaic power station and synchronous generator connected in parallel to the power grid is established, and the characteristics of low-frequency oscillation are analyzed by using damping torque. Then, the damping injection control strategy based on active power/voltage combination is studied, and its parameters are designed, and reveal the nature of its control. Based on the complex torque method, the change trend of damping torque coefficient in different scenarios is analyzed, and the mechanism of suppressing low frequency oscillation by this control is revealed. The results show that this strategy can provide moderate positive damping under different control gains and electrical distances.