| 摘要 |
<p>PURPOSE:To inhibit the mechanical vibration of a shaft system of a generator, by inverting phase in frequency components corresponding to the natural frequency of the shaft system extracted from the currents of an output system of the generator, and by adding the components to an excitation circuit. CONSTITUTION:The inflow and outflow currents of a generator 6 are detected by means of a current transformer 16, commercial frequency components are cut from the output of the current transformer 16 by means of a by-pass filter 19 and the natural frequency components of a shaft system of the generator are extracted from the output of the by-pass filter 19 by means of a band-pass filter 20. Phase is inverted by means of a phase shifter 21 in the output of the band-pass filter 20, and the output is added to an excitation circuit 22. Thus, since only the natural frequency components of the shaft system are phase-shifted at an angle of 180 deg. and added to the excitation circuit, speed electromotive force causing the vibration of the shaft system of the generator can be suppressed, and the mechanical vibration of the shaft system can be prevented.</p> |
