PUMPING OPERATION STOP CONTROL METHOD FOR AC EXCITED SYNCHRONOUS MACHINE

摘要

PURPOSE:To improve service life of circuit breaker, by decreasing the rotation of an AC excited synchronous machine then closing the blades of a pump water turbine and bringing input power approximately to zero, thereafter interrupting the circuit breaker and reducing the disturbance to the system. CONSTITUTION:Upon receipt of a pumping operation stop command, a controller 10 controls output current IG2 and output voltage VG2 of a cyclo-converter 6 to lower the rotation N of an AC excited synchronous machine 2 so as to control guide vanes of a pump water turbine 4 in closing direction corresponding to the rotation N. Upon decrease of rotation N to the lowest rotation for the lift at that time, control is made to bring input power of the AC excited synchronous machine 2 to approximately zero. Then a releasing command is fed from the controller 10 to a parallel circuit breaker 3 so as to fully close guide vanes of a pump water turbine 1 and to bring output voltage VG2 and output current IG2 from the cyclo-converter 6 to zero. Consequently, system is not disturbed at the time of stoppage of pumping operation and service life of circuit breaker is not shortened.