Integrated Control Strategy for Wind Turbine and Hydraulic Turbine in Primary Frequency Regulation

Abstract

Under the background of large-scale entry of new energy like wind power and hydropower to the power grid, more and more attention has been paid to how to use the complementary characteristics of new energy output to improve the security and the power grid’s stability. In this paper, a control strategy of combined participation of wind turbines and water turbines in primary frequency regulation (PFR) considering the flexibility of standby is proposed. First, the appropriate frequency modulation reserve capacity according to the wind speed and the operation of the turbine is determined. At the initial stage of system disturbance, the fast power control capability of variable-speed wind turbine generator is used to provide PFR fast standby capacity, give full play to its advantages of quickly suppressing frequency change rate and reducing the maximum frequency deviation, and complement the inherent defects of the lagging time of primary frequency response of conventional hydropower and thermal power units and the water hammer effect of hydropower units. Subsequently, the hydropower units provide stable active power support. In the middle and later stages of disturbance, the coordination between the fan and the water turbine unit avoids the secondary frequency drop caused by the fan entering the speed recovery process, and reduces the maximum frequency deviation and response time of the system. The example analysis verifies that the frequency modulation control strategy proposed in this paper can quickly and effectively realize the frequency control under different load sudden increment.