Method and apparatus for controlling variable-speed hydraulic power generaton system

Claim 1

A method of controlling a variable-speed hydraulic power generation system comprising an induction generator having an excitation secondary winding (1), a hydraulic machine (2) connected to said induction generator for driving the same, guide vane means (11) for controlling the quantity of water supplied to said hydraulic machine, a frequency converter (3) for applying an AC excitation to the secondary winding of said induction generator thereby to maintain the output frequency thereof at constant level, and a control unit (4, 7, 8, 12, 15; 4, 7, 8, 10, 12) for changing the quantity of water by controlling said guide vane means on one hand and for changing the amount of excitation by controlling said frequency converter on the other hand, said method comprising the steps of detecting variation in any one of the frequency of a power system electrically connected to said power generation system and a power demand from said power system to said power generation system and controlling said guide vane means by said control unit based on the detected variation so as to dampen said variation.

Claim 2

A method of controlling a variable-speed hydraulic power generation system comprising an induction generator having an excitation secondary winding (1), a hydraulic machine (2) connected to said induction generator for driving the same, guide vane means (11) for controlling the quantity of water supplied to said hydraulic machine, a frequency converter (3) for applying an AC excitation to the secondary winding of said induction generator thereby to maintain the output frequency thereof at constant level, and a control unit (4, 7, 8, 12, 15; 4, 7, 8, 10, 12) for changing the quantity of water by controlling said guide vane means on one hand and for changing the amount of excitation by controlling said frequency converter on the other hand, said method comprising the steps of detecting variation in any one of the frequency of a power system electrically connected to said power generation system and a power demand from said power system to said power generation system and controlling said guide vane means by said control unit based on the detected variation so as to dampen said variation.

Claim 3

An apparatus for controlling a variable-speed hydraulic power generation system including an induction generator (1) having an excitation secondary winding, a hydraulic machine (2) connected to said induction generator for driving the same, a guide vane means (11) for controlling the quantity of water supplied to said hydraulic machine, and a frequency converter (3) for applying an AC excitation to the secondary winding of said induction generator (1) thereby to maintain the output frequency thereof at constant level, said apparatus comprising a control unit (4, 7, 8, 10, 15; 3, 8, 9) for changing the quantity of water by controlling said guide vane on one hand and for changing the amount of excitation by controlling said frequency converter (3) on the other hand based on given set values for parameters relating to the operation of said power generation system, a detector (16) for detecting variation in any one of the frequency of a power system electrically connected to said power generation system and a power demand from said power system to said power generation system, and means (17, 18, 19; 30, 19) for processing and applying an output of said detector to said control unit.

Claim 4

An apparatus for controlling a variable-speed hydraulic power generation system including an induction generator (1) having an excitation secondary winding, a hydraulic machine (2) connected to said induction generator for driving the same, a guide vane means (11) for controlling the quantity of water supplied to said hydraulic machine, and a frequency converter (3) for applying an AC excitation to the secondary winding of said induction generator (1) thereby to maintain the output frequency thereof at constant level, said apparatus comprising a control unit (4, 7, 8, 10, 15; 3, 8, 9) for changing the quantity of water by controlling said guide vane on one hand and for changing the amount of excitation by controlling said frequency converter (3) on the other hand based on given set values for parameters relating to the operation of said power generation system, a detector (16) for detecting variation in any one of the frequency of a power system electrically connected to said power generation system and a power demand from said power system to said power generation system, and means (17, 18, 19; 30, 19) for processing and applying an output of said detector to said control unit.