Patent ID: 8420240

Claim:
A method for controlling a plurality of sodium-sulfur batteries that, in an interconnected system in which a power generation device that fluctuates in output and an electric power storage-compensation device are combined to supply power to an electric power system, are each included in the electric power storage-compensation device and compensate for output fluctuations of the power generation device, the method comprising: calculating a power reference variable by adding a first value obtained as a result of proportional action and cutting of a set value or more by a limiter, based on a value obtained by subtracting generated power of the power generation device that fluctuates in output from a power generation planned value of the interconnected system and a second value obtained as a result of proportional action and integral action, based on a value obtained by subtracting total power presently generated by the interconnected system from the power generation planned value of the interconnected system, and distributing the power reference variable to each individual sodium-sulfur battery included in the plurality of sodium-sulfur batteries as an operation reference variable; sequentially stopping individual sodium-sulfur batteries when the charge power or discharge power of each individual sodium-sulfur battery becomes 1/n or less of a rated output, n being a natural number; and sequentially restarting the individual sodium-sulfur batteries when the charge power or discharge power of each individual sodium-sulfur battery becomes x % or more of the rated output, x being a natural number.