| 摘要 |
A system coordination unit 1 includes a reverse power flow prevention circuit 10. When power output from a fuel cell 6 and/or a secondary cell 7 exceeds power consumed in AC loads and DC loads, the reverse power flow prevention circuit 10 prevents a reverse flow of excess power into a commercial power source 4. The reverse power flow prevention circuit 10 is interposed in an AC main power path 20 between a connection point of a solar cell 5 and the AC main power path 20 and each of a connection point of a fuel cell 6 and the AC main power path 20 and a connection point of a secondary cell 7 and the AC main power path 20. The reverse power flow prevention circuit 10 compares the power output from the fuel cell 6 and/or the secondary cell 7 with the power consumed in the AC loads and the DC loads. Upon determining that the former power is not less than the latter power, the reverse power flow prevention circuit 10 electrically interrupts the AC main power path 20. Consequently, the reverse power flow of the power generated by the fuel cell 6 and/or the secondary cell 7 into the commercial power source 4 is prevented by making use of only one reverse power flow prevention circuit 10. Therefore, in comparison with a case where each distributed power source other than a solar cell 5 is provided with a reverse current flow prevention device, the system can be implemented at a low cost.
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