CONTROL FOR OPERATION OF FRANCIS PUMP TURBINE

摘要

PURPOSE:To avoid the action of an overload torque to a turbine when the operation of the turbine is shifted from phase-modification to power-generation by keeping the opening degree of an inletvalve lower than that of a guide vane until the guide vane is brought to pass a fixed opening degree. CONSTITUTION:When the operation of a turbine is shifted from phase-modification to power-generation, the valve-opening speed of a guide vane is controlled to be lower than that of an inletvalve, and the time point of the initial opening of the inlet valve is delayed behind that of the guide vane by t1 seconds. That is, the opening degree (a) of the guide vane is greater than the opening degree Ai of the inletvalve before a fixed opening degree aO near a no-load opening degree, and this relation is reversed after the fixed opening degree aO. Consequently, the water pressure in the downstream of the inletvalve is balanced with the centrifugal water-pressure of a runner, and the water flux given to the runner is restrained to be essentially zero to pass through the guide vane without giving an overload torque.