Patent ID: 6927499

Claim:
An electric power system comprising a plurality of electric power generator sets, each of the electric power generator sets comprising: an engine; a generator driven by the engine; an inverter having an ability of interconnecting the generator with an external power supply; means for detecting information concerning electric power from the external power supply and electric power from the electric power generator set; means for calculating electric power and energy from the external power supply, electric power and energy from the power generator set, and electric power and energy to a load; means for recording each of the calculated electric powers and energies; and a control system for controlling output of the generator; wherein the electric power system is constructed by interconnecting the control systems with each other; and one of the control systems serving as a master unit comprises means for accumulating information on generated power required of the other power generator set(s), the information being transmitted from the other control system(s) of the other power generator set(s); calculating the load electric power of the electric power system; and determining the number of the power generator sets to be operated.