Preliminary implementation of microgrid with photovoltaic and microturbine for stand alone operation

This paper presents the preliminary implementation of microgrid system with photovoltaic and microturbine for stand alone operation. The microgrid test bed of the Institute of Nuclear Energy Research (INER) in Taiwan is selected for the study of impacts of high concentration photovoltaic (HCPV) and microturbine to be installed. The one line diagram of the microgrid is constructed and actual load profile supplied by the microgrid is collected. Based on the direct normal irradiation (DNI) and the corresponding power output of HCPV, the voltage variation of microgrid with a microturbine is solved according to the power flow analysis. Besides, the fault currents introduced from HCPV, microturbine and Taipower system are calculated to design the protection coordination of the microgrid. Three actual filed tests of the microgrid have been conducted to verify the effectiveness of the transition operation between grid connect and stand alone control of the microturbine. To verify the normal operation of HCPV, a fault contingency at the external utility system followed by the motor starting in the microgrid is simulated by computer software program. From the simulation results, it is concluded that the transient stability of the INER microgrid for stand alone operation can be guaranteed by installing a microturbine.