OPERATING METHOD FOR WATER-TURBINE AS VARIABLE SPEED HYDRAULIC MACHINERY

PURPOSE:To suppress generation of whirl oscillations and noises in a suction pipe by indicating a whirlless area where a whirl is not generated in the suction pipe by means of an engine speed per unit head and an output of a water turbine per unit head, and performing variable speed operation in a whirlless area. CONSTITUTION:In a Francis pump turbine, a runner 3 is rotated by pressure water introduced from a casing 1 and injected from a guide vane 2. A water rate flowed into the runner 3 by means of a movable guide vane 2, and output of the water turbine is controlled correspondingly to load fluctuation. In this case, an engine speed is denoted by N, effective head by H, output of the water turbine by P. An engine speed per unit head is N/H, while the output of the water turbine per unit head is P/H. A whirlless area where whirl is not substantially generated in a suction pipe 4 is indicated by the engine speed per unit head and the output of the water turbine per unit head. Variable operation is carried out in the whirlless area. The water turbine is kept in a highly efficient condition with sufficiently reducing oscillations.