Abstract:
Aiming at the frequency deterioration caused by the high penetration of wind power, a comprehensive control strategy based on dynamic task coefficients is proposed for energy storage to participate in the primary frequency regulation. Firstly, virtual inertia control and virtual droop control are used in the inertia response stage, while virtual droop control and virtual negative inertia control are used in the primary frequency regulation stage. Secondly, based on the hyperbolic tangent function, the dynamic task coefficient models suitable for the inertia response stage and the primary frequency regulation stage are constructed, respectively.According to the frequency deviation change rate and the change of frequency deviation, the proportion of frequency regulation tasks undertaken by virtual inertia control, virtual negative inertia control and virtual droop control during the primary frequency regulation process is adjusted dynamically. The unit adjustment power of negative inertia control is adjusted according to the state of charge(SOC) of energy storage and the maximum frequency difference of the system to accelerate frequency recovery. Based on the virtual droop control, a scheme with variable unit adjustment power of virtual droop control is proposed to make the unit adjustment power of virtual droop control change adaptively with the SOC. Finally, taking a certain regional power grid as an example, the effectiveness of the designed strategy is verified under the conditions of step load disturbance and continuous load disturbance.