A New Planning Model of Total Supply Capability of Distribution Network Based on Equivalent Bus

In the existing model of total supply capability, the low-voltage side buses are totally ignored. The connection was described as the feeder link from transformer to transformer. It leads to two incorrect considerations in calculation based on this model, which obviously produce errors. In this paper, a method applying equivalent bus is proposed to reformulate the model of total supply capability. Firstly, the supply transfer process after a transformer failure in actual operation was analyzed to clarify the consideration of this work, and proposed the equivalent bus; Secondly, through examples and inferences, the stable connection between equivalent bus and transformer was revealed. Thirdly, a new model of total supply capability was proposed based on the stable connection of equivalent bus, which considered the constraint of the low-voltage buses. Finally, the new model was tested in a simple distribution system with three substations, and a solution of building up the connection between equivalent bus and transformer was introduced. As the results, the calculation based on this model proposed the supply capabilities of transformers and substations, and the load distributions of buses, equivalent buses and feeders, which conclude a total error of 0.34% of the total supply capability.