A microgrid system having: a plurality of distributed power sources (740, 750); a plurality of distributed loads (771, 772, 773); and lines for connecting the distributed power sources (740, 750) and the distributed loads (771, 772, 773), the microgrid system comprising: an ESS for storing power supplied from all or a portion of the distributed power sources (740, 750) and supplying the stored power to all or a portion of the distributed loads (771, 772, 773); an ESS PCS including an interruption means configured to convert the power stored in the ESS into AC power suitable for the microgrid and to supply the AC power to the microgrid in a normal state, while blocking connection to the microgrid in an abnormal state; and a monitoring/control device configured to gradually increase a voltage output from the ESS PCS and when a failure is detected in the microgrid, to perform processing for the failure, to block the distributed power sources (740, 750) and the ESS when a failure is detected in the microgrid; characterised in that the monitoring/control device is further configured to: connect the ESS PCS to the microgrid; gradually increase the voltage output from the connected ESS PCS and determine a position where the failure occurred; and block the position where the failure occurred and connect the distributed power sources (740, 750) to the microgrid. a plurality of distributed power sources (740, 750); a plurality of distributed loads (771, 772, 773); and lines for connecting the distributed power sources (740, 750) and the distributed loads (771, 772, 773), the microgrid system comprising: an ESS for storing power supplied from all or a portion of the distributed power sources (740, 750) and supplying the stored power to all or a portion of the distributed loads (771, 772, 773); an ESS PCS including an interruption means configured to convert the power stored in the ESS into AC power suitable for the microgrid and to supply the AC power to the microgrid in a normal state, while blocking connection to the microgrid in an abnormal state; and a monitoring/control device configured to gradually increase a voltage output from the ESS PCS and when a failure is detected in the microgrid, to perform processing for the failure, to block the distributed power sources (740, 750) and the ESS when a failure is detected in the microgrid; characterised in that the monitoring/control device is further configured to: connect the ESS PCS to the microgrid; gradually increase the voltage output from the connected ESS PCS and determine a position where the failure occurred; and block the position where the failure occurred and connect the distributed power sources (740, 750) to the microgrid. an ESS for storing power supplied from all or a portion of the distributed power sources (740, 750) and supplying the stored power to all or a portion of the distributed loads (771, 772, 773); an ESS PCS including an interruption means configured to convert the power stored in the ESS into AC power suitable for the microgrid and to supply the AC power to the microgrid in a normal state, while blocking connection to the microgrid in an abnormal state; and a monitoring/control device configured to gradually increase a voltage output from the ESS PCS and when a failure is detected in the microgrid, to perform processing for the failure, to block the distributed power sources (740, 750) and the ESS when a failure is detected in the microgrid; characterised in that the monitoring/control device is further configured to: connect the ESS PCS to the microgrid; gradually increase the voltage output from the connected ESS PCS and determine a position where the failure occurred; and block the position where the failure occurred and connect the distributed power sources (740, 750) to the microgrid. connect the ESS PCS to the microgrid; gradually increase the voltage output from the connected ESS PCS and determine a position where the failure occurred; and block the position where the failure occurred and connect the distributed power sources (740, 750) to the microgrid.