Patent ID: 6210100
Filing Date: 2001-04-03
Classification: F03B,Y02E,Y10S

Abstract:
A plurality of pump-turbines sharing conduits wherein an upper reservoir-side conduit is branched in the vicinity of pump-turbine ends, the conduit portions located farther than the branch points are shared among the pump-turbines, the pump-turbines are each provided with guide vanes, and there is adopted a multi-stage closing method for the guide vanes such that when a load is rejected, said guide vanes are closed in a relatively rapid manner at the beginning and thereafter shift to a predetermined slow closing at least once, characterized in that at least a first pump-turbine out of the plural pump-turbines is provided with a rotational speed increase detector, and when it is detected that the rotational speed of said first pump-turbine has exceeded a second predetermined value higher than a rated speed, a command is issued also to at least one of the plural pump-turbines other than said first pump-turbine to limit the guide vane closing speed to a speed approximately equal to or lower than the speed after the shift to said slow closing in said pump-turbine.