Optimal Sizing and Location of Photovoltaic Generation and Energy Storage Systems in an Unbalanced Distribution System

Abstract

There has been an increasing number of renewable energy sources introduced into the distribution system to decrease the dependence on single power sources and relieve their effects related to global warming caused by power consumption. When greatly increasing renewable energy in the power system, the renewable energy connected to the power grid must be coupled with corresponding energy-storage technologies. This mechanism not only effectively improves the power floating problem but also more efficiently re-dispatches the power output. The purpose of this paper is to deal with the optimal sizing and location issue of the photovoltaic generation system and the battery energy storage system, which are proposed in order to improve the power loss, bus voltage profile, and voltage unbalance for the actual unbalanced loading distribution system of a large-scale chemical factory. The power loss, construction cost of the solar power and the energy storage systems, voltage variation ratio and voltage unbalance ratio will be treated as part of the objective function of the optimal problem. These variables are subject to various operating constraints and the voltage variation limit of the system when the photovoltaic generation and battery energy storage systems are operated. Furthermore, a refined genetic algorithm, which possesses an auto-selective crossover and mutation scheme, is proposed and applied in this paper in order to solve the optimization problem. Moreover, the simulation results are expected to demonstrate the superiority of the proposed algorithm.

Keywords

• photovoltaic generation system
• energy storage system
• voltage unbalance ratio
• voltage variation ratio
• refined genetic algorithm