A voltage deviation-memorizing reactive power controller for renewable energy sources

The power output of renewable energy sources (RESs) is inherently unpredictable and frequently deviates from its forecasted value, leading to variations in voltage. These voltage deviations may significantly impede the exploitation of RESs in power systems. Moreover, these unpredictable deviations may also cause the operating point of the system to deviate from its optimal value. This paper proposes a reactive power control method for RESs that reduces voltage deviations resulting from fluctuations in output power, and may also reduce energy loss. To this end, a simple voltage deviation-memorizing technique is applied to the reactive power controller of the RES. By memorizing the voltage deviation, the proposed method rectifies the voltage deviations caused by output power fluctuations, while compensating for deviations caused by other factors via conventional volt/var control. The efficacy of this combination of control methods is verified using simulations.