No abstract

No abstract

The "New Energy Plant" had been built at the Aichi EXPO. 2005 site as part of the "Demonstrative Project of Regional Power Grid with Various New Energies". The plant includes three types of fuel cells, a photovoltaic power generation system and a Sodium Sulfur (NaS) battery. One of the purposes of the demonstrative project is to achieve isolated operation of a micro grid without rotating generators. These new energy generators and battery are connected to the micro grid via inverters. In isolated operation, the system voltage and frequency are determined by four fuel cell inverters connected in parallel. This paper presents the control strategies, especially load share between inverters, for isolated operation of a micro grid configured with some new energy generators. Simulation results and verification test results are also shown in this paper.

Organization and a number of private enterprises. The plant includes three types of fuel cell -phosphoric acid fuel cell (PAFC), molten carbonate fuel cell (MCFC), and solid oxide fuel cell (SOFC) -with photovoltaic power generation system (PV) and Sodium Sulfur (NaS) battery. One of the purposes of the demonstrative project is to verify supply/demand control, etc. to minimize the effect on the utility grid. Isolated operation of a microgrid is an ultimate state to be no interaction between utility grid and the microgrid. It also increases value of the microgrid.These new energy generators are connected to the microgrid via inverter and there are no synchronous generators. There are no established techniques to startup and control voltage and frequency of such system. The authors carried out a verification test of isolated operation of the microgrid. This paper presents the control strategies for isolated operation of a microgrid configured with some new energy generators. Simulation results of microgrid excitation, load share operation, and response for load change such as an induction motor is connected are shown. These results are reflected to the verification test condition. This paper also presents the test result of isolated operation of the microgird on Aichi EXPO. 2005.The system had separated from utility grid, and performed stable controllability for load change for around three weeks. But total amount of load was limited because of bus voltage drop. Figure 1 shows a part of power generation results of new energy generators from 30th Sept. to 11th Oct. The microgrid was energized by a PAFC on 30th Sept. The 2nd to 4th PAFC were synchronized to the 1st PAFC and stable load share operation was confirmed. NaS battery was connected and started operation on 1st Oct. SOFC and MCFC started power generation on 7th Oct. and 10th Oct. respectively.-16 -

No abstract