Optimal control of power unit with doubly fed machine

An adjustable-speed unit with a doubly-fed machine running both in generator and pump modes is dealt with. Operation of a power unit with a doubly fed machine driven by a Francis turbine regulated at the optimal speed is analyzed and compared to the cases when the speed is kept constant. The response of the system to changes in demanded active power command has been investigated. Control of active power consumed in pump mode is analyzed. The effect of a high voltage distribution line on the operation of the system has been taken into consideration.