Abstract
•Provide stable and reliable optimal control system performance for MG UFLS scheme.•Increase the rentability and profitability of the microgrid UFLS scheme.•Control all fluctuations of frequency optimally to guarantee a flexible operation of an MG.•Improve the lifecycle cost of all significant expensive equipment involved in the design of MG.•Combine linear objective functions to handle UFLS problems of the MG system.
The microgrid (MG) implementation has changed the power system's configuration, and it has optimally permitted the integration of renewable energy resources (RERs). This paper addresses an optimal load management control method application for an economic load shedding problem. The control scheme is based on coordination of the diesel generator (DG) system combined with a standalone MG that contains RER (wind and photovoltaic (PV), two biomass generation systems and an energy storage system (ESS). The control model minimises the DG unit's fuel cost incorporated into an MG where a milling plant is part of the loads. The optimal control scheme has been executed to minimise the DG's operating cost, maximise the energy from RERs and finally increase the MG's profit during the load shedding operation. This strategy develops an under-frequency load shedding (UFLS) scheme to control the MG based-multiobjective optimally. An adaptive UFLS strategy is designed to coordinate the system behaviour by adjusting the distributed generation in the function of variation in the demand side. It is observed that it is economically reliable to solve the load shedding problem and save the fuel cost of the diesel generator in the MG power system by optimally fashioning the control scheme. The profitability of this adaptive strategy is impressive, which is about 100%. Besides, the application of different distributed energy structures in an MG impacts the demand side. It implies adjusting the total power supply fluctuations, which remarkably improves the MG power system's lifecycle cost (LC) and stabilise the system frequency and voltage.