Abstract: The present invention relates to the coordinated control method of torsional stress relay in large thermal power plants' generators (300 MW and above), which will be adopted when shaft torsional oscillations occur. This invention also publishes a method of realizing selective trip the generators and the trip criterions which are implemented by the torsional stress relay and coordinated control master station (Tmaster). Tmaster will real-time monitor the operating status of the generators and TSR, TMaster will also real-time generate a trip priority level sequencing by analyzing the unit output. When generators occur subsynchronous resonance and shaft torsional oscillation, this method can ensure that TSR will trip some generators of the power plant according to the real-time generated trip strategy to inhibit the shaft torsional oscillation and safeguard the units.

Abstract: A single-pole type generator with low loss magnetic core is excited by a field coil that is part of a low loss series resonant circuit tuned to a desired AC power frequency, which may be frequencies such as 50 Hz or 60 Hz or 400 Hz. The series resonant circuit is excited at the resonant frequency. The resulting resonant behavior of the excitation circuit automatically provides the high driving voltages and sinusoidal energy storage patterns needed to efficiently modulate the magnetic field at the desired power frequency. This modulation of the excitation field is amplified by mechanical power from a rotating shaft and modulates the output current and voltage of a single phase output circuit of the single-pole type generator at that power frequency in a sinusoidal pattern thus delivering alternating current power without any requirement for further electronic rectification, commutation or processing.

Abstract: A poly-phase high frequency alternator with a low-loss magnetic core is excited by a low-loss field coil that is part of a series resonant circuit tuned to a desired AC power frequency which may be 50 or 60 Hz. The series resonant circuit is excited at the resonant frequency. The resulting resonant behavior automatically provides the high driving voltages and sinusoidal energy storage patterns needed to efficiently modulate the field inductance at 50 or 60 Hz. Modulating the field at the desired AC power frequency modulates the alternator output voltage at that frequency. The poly-phase alternator output is rectified into a single phase and commutated with respect to the load at the zero crossing of each half cycle of the AC power frequency. This produces a single phase power frequency AC output.