| 摘要 |
<p>PURPOSE:To prevent the influence of a system failure on a system protective system by estimating the phase of the secondary current of a generator-motor at the time of the opening of a breaker due to the system failure, based on the phase of the secondary current and a slip of the generatormotor at the time of the detection of the system failure. CONSTITUTION:If a failure of three-phase short circuit occurs in a system 8, a system failure detector 10 detects the system failure through the overvoltage of the secondary wiring circuit of a generator-motor 1, and outputs a detection signal to a control 't 4. The control device 4 outputs the slip value and the phase of secondary current of the generator-motor 1 to a phase operation unit 11 through a slip signal 4s and a phase signal 4p, respectively. The phase operation unit 11 carries out an operation to obtain the phase of the secondary current of the generator-motor 1 when a predetermined operation time of a breaker 7 passes, and outputs the result of the operation to an excitation selector 12. The excitation selector 12 compares the phase angle of the output phase signal 11p with 12 angles, and outputs direct current excitation corresponding to the closest angle to a switch 6. This enables continuous operation regardless of any system failure.</p> |
