Power System Operation Simulation Considering Frequency Security with Coordination of Day-Ahead Unit Commitment and Intra-Day Optimal Operation

As a large number of synchronous units are replaced by low inertia new energy sources, the frequency security of power system is facing severe challenges. Power system operation simulation of multi-type generators needs to consider frequency security constraints, and faces the problem of day-ahead and intra-day coordination. In this paper, a power system operation simulation method considering frequency security with coordination of day-ahead unit commitment and intra-day optimal operation is proposed. This method constructs a frequency response model of power system containing hydropower, thermal power, wind, solar, nuclear, storage and UHVDC. The frequency security constraints are obtained by Simulink simulation. The day-ahead unit commitment model takes the day-ahead wind-solar-hydropower prediction scenarios as the boundary, and takes the minimum start-up and operation cost of multi-type generators as the objective. The intra-day optimal operation model takes the minimum operation cost of multi-type generators as the objective under the intra-day wind-solar-hydropower prediction. When the frequency security is not satisfied, the frequency security cut constraint is returned and re-solved. Finally, through the IEEE24 node test system, it is verified that the method can ensure that the minimum frequency of the system under high power disturbance is not exceeded under the premise of economy, and ensure the frequency safety of the system.