Identification Method of 220kV Key Substation Based on Guaranteed Supply Requirement Constraint

To ensure the integrity of the regional power grid structure and minimize load loss, the key 220kV substations in the power grid are identified according to the operation state. It provides decision support for the power grid disaster warning and control. In this paper, the proportion of the important load to the rated capacity of the substation is analyzed first. At the time of heavy load, the substation load rate after the maximum capacity main transformer N1 failure is calculated. Next, based on the non-transferable load and the important load, the ratio between it and the rated capacity of the substation is analyzed and calculated. According to the output power of the power source in the substation supply area through the 110kV voltage level and below, the ratio between the output power of the power source and the important load is calculated. Then, the sum of power flowing into the substation node and the power flowing out of the substation node are analyzed, and the ratio between the power flowing out and the power flowing into the substation node is calculated. Finally, the objective function is established. The 220kV substations are sorted according to the value of the objective function. The effectiveness and adaptability of the proposed method are verified by a provincial power grid.