Control method for multi-stage hydraulic machine

摘要

A multi-stage hydraulic machine comprises a rotatable shaft; a plurality of runners fixed to the shaft and arranged from a highest-pressure stage to a lowest-pressure stage; runner chambers in which are respectively housing the runners; a return channel for connecting adjacent ones of said runner chambers with each other; movable wicket gates provided at least in the highest-pressure stage and capable of moving between a position in which the movable wicket gates block the channel and a position in which the movable wicket gates open the channel; and a casing connected to the highest-pressure stage. In a control method for the hydraulic machine, the wicket gates are closed and highly pressurized water is fed through a feed pipe in an outer circumferential portion of the runner chamber of the highest-pressure stage defined inside of the movable wicket gates, said water sequentially reaching the lower pressure stages through the return channels. The air at the central portion of each of the stages is then exhausted in a sequential manner from the highest-pressure stage to the lowest-pressure stage.