Evaluation Method of Alternative Benefit of Energy Storage in 220kV Substation

The continuing increase in the penetration of renewable energy and the increase in regional power load has led to the inability of the main transformer capacity of some substations to satisfy the capacity demand brought about by renewable energy access and load growth. Two solutions are usually adopted: the capacity expansion of the substation main transformer and energy storage configuration. Based on the current main transformer capacity of the 220kV substation, the N-1 failure of the main transformer of the substation and the load rate constraints in the case of load transfer are considered and analyzed in this paper. The transferred load of the 220kV substation is calculated. Then, according to the non-transferable load, considering the power constraints of energy storage, the power constraint of energy storage as a load and the charge and discharge constraint of energy storage, whether the energy storage configuration on the grid side can satisfy the main transformer N-1 demand of 220kV substation is analyzed. Finally, the efficiency index of the replacement capacity of the main transformer capacity is proposed, and its critical value is given. The benefit of configuring energy storage and expanding a main transformer in the substation is analyzed. The effectiveness and adaptability of the proposed method are verified by a practical regional power grid.