REVERSIBLE PUMP-TURBINE FOR HIGH HEAD HIGH FORCED DRAFT

摘要

PROBLEM TO BE SOLVED: To perform idle running for a long time without the excessive increase of a shaft input and the excessive increase of leakage of gas when a runner is caused to effect idle running of a runner. SOLUTION: A reversible pump-turbine comprises a draft tube 5 connected to the lower end part of a runner chamber 4 to contain a runner 2; a first runner chamber drain pipe 8 to intercommunicate the side pressure chamber of the runner chamber and the draft tube and a second runner chamber drain pipe 9 to interconnect an outer peripheral flow passage, running between the runner of the runner chamber and a guide vane aligned on the outer periphery thereof, and a draft tube flow passage. By injecting high pressure air in the runner chamber, a water level is forcibly lowered to the level of the draft tube and a runner is caused to effect idle running of the runner. In this case, the first runner chamber drain tube 8 is connected to a draft tube flow passage part in a range of 0.35D, wherein D is the outlet diameter of the runner, in air above the upper limit of a specified forced lowering water level or the second runner chamber drain pipe 9 to the flow passage part of the draft tube in a range of 0.35D in water below the lower limit of a specified forced lowering water level in the draft tube 5.