Patent ID: 8742629

Claim:
A residential electric power storage system, comprising: a lead-in wire extending from a commercial power supply system connected to an electric power generation device; a distribution line connected to said lead-in wire for supplying an electrical load of a residence with electric power; an electric power storage device configured to be capable of supplying said electrical load with electric power; a voltage sensor sensing a voltage of said lead-in wire; a current sensor sensing a current charged to said electric power storage device through said distribution line; an electric power adjustment unit provided between said electric power storage device and said distribution line and adjusting electric power charged to said electric power storage device through said distribution line; and a controller controlling said electric power adjustment unit, if said lead-in wire has voltage smaller than a threshold voltage, said controller performing current control controlling said electric power adjustment unit to match the current that is charged to said electric power storage device to a command value, whereas if said lead-in wire has voltage larger than said threshold voltage, said controller performing voltage control controlling said electric power adjustment unit to match the voltage of said lead-in wire to a command value.