Electric power system

A power system connected to a power grid, comprising:

• a plurality of power conditioners;
• and
• a central management device that manages the plurality of power conditioners,
• wherein the central management device includes:
• a detector that detects regulation subject power;
• an index calculator that calculates an index for controlling individual output powers of the plurality of power conditioners such that the regulation subject power matches with target power, the calculating of the index being based on the regulation subject power and the target power;
• and
• a transmitter that transmits the index to the plurality of power conditioners,
• wherein each of the plurality of power conditioners includes:
• a receiver that receives the index;
• a target power calculator that calculates the individual target power of the power conditioner based on an optimization problem using the index;
• and
• a controller that regulates the individual output power of the power conditioner to the individual target power.