Analytical Formulae and Algorithm for Substation Optimization Planning with Interruption Cost Being Considered
Substation optimization planning is the key to avoid wasteful investment. In the absence of detailed data, new analytical formulae are presented for the substation optimization planning with the customer interruption cost being considered, based on the assumption of uniform load distribution. In the simplified models of analytical formulae, the total cost is represented by a function of substation number, and the line cost is calculated according to the estimated number and power supply radius of feeders. Based on the extreme value method, an algorithm is proposed for the single-stage substation optimization planning. Through the application of proposed models and algorithm to a real distribution network, it is shown that the larger the proportion of cable circuits is or the higher the customer interruption cost is, the greater the optimal number of substations is and the smaller the substation capacity is, and larger load density corresponds to bigger substation capacity and number. INTRODUCTION Substation optimization planning is to obtain the planning scheme of correctness and scientificalness, and much work of data preparation and input is required for complicated models and algorithms. 1-3 In the absence of data (such as those of detailed load distribution), substation optimization planning may be performed under some simplified conditions. Therefore, it is important to develop simplified models and algorithms which can satisfy a certain calculation precision based on small amount of related data. Currently, there are some related models and algorithms for the approximate estimation of substation number, capacity and power supply radius, 4-10 in which the substation capacity is regarded as a decision variable. In reference 6, the interruption cost is taken into account in the objective function of annual total cost with a separated reliability evaluation model being employed. In this paper, based on the assumption of uniform load distribution, new simplified models are presented for substation optimization planning, resulting in the new analytical formulae of optimal substation number and capacity with the interruption cost being considered. Also, a simple algorithm is proposed for single stage substation optimization Yu-sheng HU 1 , Man ZHANG 2 , Jin-qian ZHAI 1 , Zhu-ding WANG 2 , Xiao TAN 2 First author, Yu-sheng HU, Zhengzhou Power Supply Company, Zhengzhou 430030, China. Corresponding author: 381108932@qq.com