Abstract
In recent years，with progress of the deregulation of the electric power industry，safe and economical operations are required in the power system. So the investigation of optimal power flow is emphasizing more in such situation. The requirement for voltage safety operation is to keep bus voltage at pertinent range，and the requirement for economical operation is minimization of generating costs. In this paper, we examined dynamic optimal power flow method for operation to minimize generating costs to keep bus voltage at pertinent range and to minimize number of changing of discrete type reactive power regulators.
