Optimization of Photovoltaic Systems Using Batteries for Peak Demand to Improve Rural Electrification

摘要

The paper proposes the optimization of photovoltaic (PV) systems using batteries for peak load demand in a rural area grid-connected system. The objectives of this study are to improve existing grid systems in remote areas because of an increasing number of new users, and to evaluate the economic feasibility of PV systems, using batteries at peak demand, in a rural distribution system in a remote area. The Decentralized Battery Energy Management (DBEM) method involves the separation of strings of battery groups, to minimize the loss of power supply, cost of energy and wasted electrical energy. It was modified and utilized to satisfy the peak demand load. The optimal sizing of a PV system using batteries at peak load demand was investigated by applying the Strength Pareto Evolutionary Algorithm 2 (SPEA2) and was examined using the AC load flow method and the AC Optimal Power Flow (OPF) computation. Battery charging and discharging processes applied the State of Charge (SOC) as a decision parameter to control overcharge and discharge batteries. The design is a trade-off between the performance of voltage regulation, the minimum cost of energy, loss of battery power supply at peak load demand, wasted energy and line losses. This study focuses on a remote area power system that has weak radial networks, especially at peak demand. The voltage drop and rise problems are focused and solved by using switched capacitor banks and PV systems. The designed size of switched capacitor banks can maintain the voltage levels within the permitted voltage limitation, demonstrated by calculating the AC OPF. The optimal sizing of PV systems using batteries at peak demand can to improve the voltage levels of the grid-connected system and to decrease electricity production, CO_2 emissions and line losses of the grid-connected system. In addition, the grid-connected PV systems using the DBEM method with small, medium and large sizes of three battery groups can reduce PV capacities leading to lower cost of energy than the systems using one battery group. As a result, if a DBEM system can be successfully developed, grid-connected PV systems using the DBEM system can be more profitable than using one battery group.