Unit Commitment Considering Inertia Supply of Both Source and Demand Sides

With the large-scale access of new energy to the power system, the system inertia continues to decline. The frequency security problem caused by insufficient system inertia seriously threatens the safe operation of the system. Therefore, inertia demand and inertia supply capacity need to be considered when making dispatching plans. However, the inertia supply capacity of demand side has not been fully investigated. In this context, this paper first establishes the inertia supply capacity model of both source and demand sides. On the source side, the inertia supply capacity of synchronous generators and wind turbine virtual synchronous machines(VSM) is considered comprehensively; on the demand side, a new evaluation method for inertia is proposed to find the inertia supply capacity of load. Then, based on the system dynamic frequency response, the inertia demand constraints based on the rate of change of frequency(RoCoF) and the frequency nadir are constructed. Finally, a unit commitment(UC) model considering inertia demand constraints is established, and the established model is tested in the modified IEEE-39 system. The results verify the effectiveness of the proposed inertia evaluation method; the proposed UC model can effectively improve the economy of the dispatching scheme while ensuring the system frequency safety.