Rule-Based Peak Shaving Using Master-Slave Level Optimization in a Diesel Generator Supplied Microgrid

Abstract

This paper proposes a rule-based peak shaving method using master-slave level optimization and presents its impact on an isolated diesel generator (DG) supplied microgrid. The DG is connected to low voltage (LV) ac bus through a back-to-back converter. This DG supplies power to a modified CIGRE residential distribution system which consists of residential loads and renewable energy sources (RESs). In such a system the fuel consumption of DG not only depends on the LV ac bus power requirement but also on its rated power. The rated power of DG can be reduced through the peak shaving application. In this scenario, a battery energy storage system (BESS) is connected at dc bus of the back-to-back converter for the peak shaving of DG power. The rule-based peak shaving method is proposed for determining BESS charge/discharge schedules considering the day-ahead LV ac bus powers over a day as inputs. For that firstly the LV ac bus powers are optimally obtained using a slave level optimization. In order to obtain the optimal peak DG power a master level optimization is used which determines the optimal control inputs for the rule-based control. The proposed peak shaving control method is tested in MATLAB.