Control of low voltage microgrid in autonomous operation mode

In this paper a control strategy is presented allowing a low voltage microgrid (MG) to operate autonomously when being disconnected from the utility network. The considered MG consist of photovoltaic panels (PV), gas microturbine (MT), loads and energy storage (ES). It was assumed that in autonomous mode the microgrid operates according to Single Master Operation (SMO) strategy and the ES is a reference voltage source. Control algorithms for power electronic converters coupling energy resources with the microgrid are discussed. Then, an idea of central controller is presented, which function is to determine set points for MT according to active and reactive power changes in the microgrid. Simulation model of the microgrid has been developed using PSCAD/EMTDC platform. Selected simulations results are presented in the paper which illustrate the operation of control systems and show the MG behavior after transition from grid-connected to autonomous operation mode.