배전계통 규정 전압 유지를 위한 에너지 저장 장치의 온라인 추정 및 재운영 계획

Abstract

This paper presents an online method to schedule energy storage systems (ESSs) every 15 minutes for voltage regulation at specific nodes with renewable energe resources (RESs) in a distribution network. The proposed method consists of two phases: the first phase is to estimate the real-time states for the distribution network; the second phase is to find the optimal rescheduling of ESSs based on estimated states to maintain voltage magnitude at critical nodes. In the first phase, we implemented WLS-based state estimation (SE) considering conventional measurements (CMs) as well as psudomeasurement for observerbility and then calculate new operating states by using measurements of phasor measurement units (PMUs) in a post-processing. In the second phase, an optimization problem of online scheduling of ESSs is formulated by using real-time operating states and its variances. Optimization problem is subjected to grid and ESSs operating condition modeled considering the states and its variances. The genetic algorithm (GA) is used to solve the optimization problem which was changed to unconstrained optimal problem by using the penalty function. Simulation case studies are implemented in a modified IEEE 33 Node Test Feeder with forecasted data on the load demand, and generation of RESs. The case study is performed for two scenarios that one is a case with forecasted error for load demand and generation of RESs, and the other is a case with unpredictable disconnection of wind turbine (WT) in the distribution network due to high prediction error with regard to wind speed. The results demonstate that the proposed method is effective to reduce voltage deviations induced by forecasted error or abrupt disturbance, compared to the conventional method to only use day-ahead forecasted planning of ESSs.