Optimization of Reserve With Different Time Scales for Wind-Thermal Power Optimal Scheduling Considering Dynamic Deloading of Wind Turbines

In the power system with high proportion of wind power, a day-ahead and intraday coordinated optimal scheduling model of wind power and thermal power units (TPUs) is established considering variable virtual inertia. Firstly, the frequency regulation characteristics of wind turbines (WTs) are analyzed, the feasibility of reserve of WTs is elaborated, and the dynamic deloading strategies of WTs in different wind speed zones are proposed. Then, the feasibility of variable virtual inertia realized by rotor overspeed control (ROC) of WTs is analyzed, which is combined with synchronous inertia of TPUs to deduce the deloading level constraints of WTs and minimum inertia constraints of power system considering inertia demand. Referring to the characteristics of reserve resources in different time scales on the generation side, the reserve capacities of TPUs are divided into minute and second levels according to response time, and the scheduling strategy of reserve capacity in different time scales is proposed, so as to improve the flexibility of TPUs and realize the refined management of reserves. Simulations indicate that the proposed model and method can effectively improve the inertial support capability of the system and reduce the operation cost.