전기요금 저감을 위한 고속철도 변전소 에너지저장장치 용량산정 프로그램 개발

Abstract

We present a method for calculating the optimal capacity of an energy storage system (ESS) to reduce the electricity spend of a high-speed railway substation, and introduce an ESS optimal capacity calculation program based on the presented method. In order to represent the spend in a realistic manner, the optimization problem to generate an ESS’s charging/discharging schedule is formulated by considering the basic cost determined by the maximum load (kW) and the electricity usage cost determined by the time-based electricity consumption (kWh). A relaxation method to convert the formulated nonlinear optimization problem to a linear optimization problem that can be solved quickly by using a noncommercial solver is then presented. Based on the scheduling method, a method to determine the optimal capacity of an ESS is presented. The proposed capacity determination method consists of two steps. First, a set of capacity candidates to request detailed specifications from an ESS manufacturer is generated by using rough ESS data. Using the detailed specifications provided by the manufacturers, the optimal ESS capacity is determined in the second step.