Means for damping mechanical torsional oscillations of an electric a.c. generator
AssigneeASEA Aktiebolag
InventorHans Bjorklund
Life of this patent
Estimating the term…
Abstract
For damping torsional oscillations of an electric a.c. generator, a speed-sensing member, for example a tachometer-generator, is connected to the a.c. generator. The speed-dependent signal generated by the speed-sensing member is supplied to a band-pass filter which is adapted to the natural frequency of the torsional oscillations. The output signal of the band pass filter is supplied directly to the control angle determining means of a converter connected to the generator. In this way, the power of the converter is modulated in such a way that the oscillations are damped.
Claims7
A high voltage direct current power transmission apparatus comprising a static convertor having d.c. terminals for connection to a d.c. network and a.c. terminals for connection to an a.c. network, said a.c. network comprising an electric a.c. generator, said converter being arranged for transmitting power between said a.c. and d.c. networks, said convertor having current regulator means for controlling the convertor current in accordance with a reference signal supplied to said current regulator means, control means for inflluencing the control angle of the convertor and having an input connected to an output of said current regulator means, sensing means for forming a signal which corresponds to speed variations of the generator with a frequency corresponding to a natural frequency of torsional oscillations of the generator, and means for supplying said signal to said control means so as to influence directly the control angle of the convertor and thereby the active power of the convertor for damping the oscillations.
A high voltage direct current power transmission apparatus comprising a static convertor having d.c. terminals for connection to a d.c. network and a.c. terminals for connection to an a.c. network, said a.c. network comprising an electric a.c. generator, said converter being arranged for transmitting power between said a.c. and d.c. networks, said converter having current regulator means for controlling the convertor current in accordance with a reference signal supplied to said current regulator means, control means for influencing the control angle of the convertor and having a first input connected to an output of said current regulator means, sensing means for forming a signal which corresponds to speed variations of the generator with a frequency corresponding to a natural frequency of torsional oscillations of the generator, and means for supplying said signal to a second input of said control means so as to influence directly the control angle of the converter and thereby the active power of the convertor for damping the oscillations.
Dependencies are inferred from the claim text.