摘要 |
A control system of pumping operation comprises a cycloconverter (6) for converting AC power from a AC power system (4, 8) into AC power having a given frequency, an AC exciting generator-motor (2), having a stator side electrically connected to the AC power system (4, 8), having a rotor side electrically connected to the cycloconverter (6), and having a rotor shaft mechanically coupled to a pump-turbine (1) by which the pumping operation is carried out, a circuit breaker (3) inserted between the AC power system (4, 8) and the AC exciting generator-motor (2), a rotation speed controller (11-13, 100, 103-109) for controlling a rotation speed (N) of the AC exciting generator-motor (2) such that the rotation speed (N) becomes slow when the pumping operation is to be stopped, an AC excitation controller (14, 108, 109) for decreasing a degree of excitation effected by the cycloconverter (6), wherein decreasing of the excitation degree starts when the rotation speed (N) of the AC exciting generator-motor (2) reaches a given minimum value (Fig. 4), and a circuit breaker controller (11, 12, 100, 101) for turning off the circuit breaker (3) when input power (VG1, IG1), supplied from the AC power system (4, 8) to the AC exciting generator-motor (2) becomes substantially zero. |