Improved analytical method of power supply capability on distribution systems

Accurate calculation and evaluation of power supply capability (PSC) for distribution systems is a promising research direction in urban power grid planning. Traditional calculation methods only consider transformer interconnection and N − 1 contingency in evaluating PSC, without considering interconnection capacity constraint and short-term overloading of main transformers, etc. This paper proposes an improved analytical calculation method for calculating PSC. Firstly, based on traditional calculation process, a connection constraint matrix is built to stand for the capacity differences of tie lines inter different substations. Secondly, a virtual link matrix and load transfer matrix are defined to describe load transfer capability of the overloaded transformer. Thirdly, some improved analytical steps, including minimum element searching, longitudinal adjustment, deviation straightening, are proposed to search the maximum loading capability of connection units between main transformers. Lastly, as demonstrated on an actual distribution system, it is concluded that PSC could be calculated more accurately in order to provide new solutions to distribution system planning.