Optimisation Method of Distribution Network Planning and Construction Investment Analysis Considering the Substation Requirement

The load characteristics of the distribution network are affected by the accessing of high-penetration distributed photovoltaics, which affects the upgrade time of related equipment and the investment efficiency of the distribution network upgrade. In this paper, the load ratio of the substation under the N-1 condition is analyzed from the point of view of the substation load. According to the historical data, the load growth rate is obtained. The overload years of the substation N-1 with the load growth are calculated. Then, the midday distributed photovoltaic output is analyzed, and the capacity ratio and the output simultaneity are considered. Based on the development of distributed photovoltaics, the period of power transmission in the noon hour of the substation is calculated. Finally, according to the investment of substation reconstruction and expansion, the annual investment of the power grid under two scenarios of down-grid demand and up-grid demand is calculated, respectively. The evaluation index of distribution network investment is proposed. The effectiveness and adaptability of the proposed method are verified by taking a provincial regional power grid substation as an example.