US4080559A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Torsional protective device for power system stabilizer
Assignee: General Electric Co
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Filing: 1976-11-15
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Granted: 1978-03-21
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Expires: 1996-11-15
Abstract
Abstract Power system stabilizers are used in the excitation systems of large shaft driven synchronous dynamoelectric machines for the purpose of enhancing the dynamic stability of power generating systems. Such stabilizers using speed, power or frequency as an input signal when applied with high initial response excitation systems are effective in damping low-frequency local or inter-tie mode oscillations which may occur in the system. The power system stabilizer may adversely affect torsional damping at higher frequencies. The adverse effects of a power system stabilizer at shaft torsional frequencies are obviated by providing a torsional oscillation protection device comprising a composite band-reject filter of the present invention which attenuates the power system stabilizer output at the shaft natural torsional frequencies without introducing an excessive phase lag at the local or inter-tie mode frequencies. The invention is applicable at a universal shaft pickup location and means are provided for detecting any failure in the torsional protective device whereby the power system stabilizer output may be discontinued in the event there is a failure in torsional protection.
Inventors
- 👤 George F. Wright
- 👤 Dale A. Swann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 06:28
CPC Classifications
H; H02; H02P; H02P9/00; H02P9/10; H02P9/105; H02H; H02H7/00; H02H7/06; B; B60; B60L; B60L2270/00; B60L2270/10; B60L2270/14; B60L2270/145; Y; Y02; Y02T; Y02T10/00; Y02T10/60; Y02T10/64
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
122 words
In combination with a shaft driven synchronous dynamoelectric machine, a power system stabilizer provides a damping signal to the excitation control of the dynamoelectric machine for damping low frequency oscillations which may occur in the driving shaft; a torsional oscillation protection means is provided in combination with the power system stabilizer for attenuating the power system stabilizer output at higher frequency shaft torsional frequencies of oscillation wherein said torsional oscillation protection means includes: a composite band-reject filter comprising a plurality of biquad filter elements connected in series, wherein each filter element has a tuned frequency at or near a shaft torsional frequency whereby the band-reject filter attenuates the power system stabilizer output within the total frequency bandwidth of the shaft torsional frequencies.
Claim 2
Dependent Claim
122 words
In combination with a shaft driven synchronous dynamoelectric machine, a power system stabilizer provides a damping signal to the excitation control of the dynamoelectric machine for damping low frequency oscillations which may occur in the driving shaft; a torsional oscillation protection means is provided in combination with the power system stabilizer for attenuating the power system stabilizer output at higher frequency shaft torsional frequencies of oscillation wherein said torsional oscillation protection means includes: a composite band-reject filter comprising a plurality of biquad filter elements connected in series, wherein each filter element has a tuned frequency at or near a shaft torsional frequency whereby the band-reject filter attenuates the power system stabilizer output within the total frequency bandwidth of the shaft torsional frequencies.
Claim 3
Dependent Claim
68 words
The combination recited in claim 1 wherein the power system stabilizer further comprises: transducer means connected to the dynamoelectric machine and providing an output signal indicative of an input signal deviation from a reference synchronous frequency; and, signal conditioning means receiving said output deviation signal and providing a phase corrected output signal to said composite band-reject filter for attenuating said phase corrected output signal at shaft torsional frequencies.
Claim 4
Dependent Claim
66 words
The combination recited in claim 1 further including a composite band-pass filter comprising a plurality of biquad filter elements connected in series, wherein the composite band-pass filter has an exact inverse character to the composite band-reject filter, said band-pass filter connected in series with said band-reject filter and providing an output signal substantially indentical to the input signal of said band-reject filter at shaft torsional frequencies.
Claim 5
Dependent Claim
158 words
The combination recited in claim 3 wherein the power system stabilizer comprises in series: transducer means connected to the dynamoelectric machine and providing an output signal indicative of an input signal deviation from a reference synchronous frequency; first signal conditioning means receiving said transducer output signal and providing a phase corrected output signal; a high pass, washout filter for eliminating low frequency and steady-state signal components; an output board including signal amplifier means; the torsional oscillation protection means wherein the composite band-reject is connected between the first signal conditioning means and the washout filter; and, the composite band-pass filter has an input signal from the washout filter; second signal conditioning means, substantially identical to the first signal conditioning means, connected to receive said transducer output signal; and means comparing the respective output signals from the second signal conditioning means and from the composite band-pass filter whereby an output malfunction warning signal is generated upon a predetermined signal difference.
Claim 6
Dependent Claim
161 words
In combination with a shaft driven synchronous dynamoelectric machine, a power system stabilizer provides a damping signal to the excitation control of the dynamoelectric machine for damping low frequency oscillations which may occur in the driving shaft; a torsional oscillation protection means is provided in combination with the power system stabilizer for attenuating the power system stabilizer output at shaft torsional frequencies; said power system stabilizer comprising: speed sensing means providing an output signal proportional to shaft speed; transducer means converting the output speed signal into a frequency deviation signal; signal conditioning means receiving said frequency deviation signal and providing a phase corrected output signal; a composite band-reject filter receiving the output of said signal conditioning means, said filter comprising a plurality of biquad filter elements connected in series with one another, each filter element being tuned at or near a different shaft torsional frequency whereby the output of the power system stabilizer is attenuated in the shaft torsional frequency range.
Claim 7
Dependent Claim
161 words
In combination with a shaft driven synchronous dynamoelectric machine, a power system stabilizer provides a damping signal to the excitation control of the dynamoelectric machine for damping low frequency oscillations which may occur in the driving shaft; a torsional oscillation protection means is provided in combination with the power system stabilizer for attenuating the power system stabilizer output at shaft torsional frequencies; said power system stabilizer comprising: speed sensing means providing an output signal proportional to shaft speed; transducer means converting the output speed signal into a frequency deviation signal; signal conditioning means receiving said frequency deviation signal and providing a phase corrected output signal; a composite band-reject filter receiving the output of said signal conditioning means, said filter comprising a plurality of biquad filter elements connected in series with one another, each filter element being tuned at or near a different shaft torsional frequency whereby the output of the power system stabilizer is attenuated in the shaft torsional frequency range.
Claim 8
Dependent Claim
84 words
The combination recited in claim 5 further including a composite band-pass filter having an exact inverse character to the composite band-reject filter, said band-pass filter including a plurality of biquad filter elements connected in series to one another, each filter element being tuned at or near a different shaft torsional frequency; said composite band-pass filter being connected in series to the band-reject filter whereby, at shaft torsional frequencies, the output of the band-pass filter is the same as the input to the band-reject filter.
Claim 9
Dependent Claim
51 words
The combination recited in claim 6 further comprising comparator means for comparing the input of the band-reject filter with the output of the band-pass filter, said comparator means providing an output signal whenever the output of the band-pass filter differs from the input of the band-reject filter by a predetermined amount.
Claim 10
Dependent Claim
113 words
The combination recited in claim 7 wherein the composite band-reject filter and the composite band-pass filter each comprise a plurality of biquad filter elements and wherein each filter element includes a summing circuit wherein the signal input to the filter element provides a first input to the summing circuit through a first resistor R 1 ; wherein the signal output of the filter element provides a second input to the summing circuit through a second resistor R 2 ; wherein the band-reject filter is characterized by R 1 >R 2 and the band-pass filter is characterized by R 1 <R 2 and wherein R 1 and R 2 are interchangeable with one another.
Claim 11
Dependent Claim
188 words
In combination with a shaft driven synchronous dynamoelectric machine, an improved power system stabilizer for damping local or inter-tie mode oscillations in the driving shaft; said power system stabilizer providing a phase shifted output signal in response to a frequency related input, the improvement comprising: means for attenuating the power system stabilizer output at shaft torsional frequencies, said means including a composite band-reject filter including a plurality of biquad filter elements connected in series, wherein each filter element has a tuned frequency at or near a different shaft torsional frequency whereby the band-reject filter attenuates the power system stabilizer output within the total bandwidth of shaft torsional frequencies; a composite band-pass filter including a plurality of biquad filter elements connected in series, wherein each filter element has a tuned frequency at or near a different shaft torsional frequency, said composite band-pass filter connected in series with said composite band-reject filter; means for comparing the input to said band-reject filter with the output from said band-pass filter to determine a signal difference whereby if the signal difference exceeds a predetermined amount the power system stabilizer output may be interrupted.
Claim 12
Dependent Claim
188 words
In combination with a shaft driven synchronous dynamoelectric machine, an improved power system stabilizer for damping local or inter-tie mode oscillations in the driving shaft; said power system stabilizer providing a phase shifted output signal in response to a frequency related input, the improvement comprising: means for attenuating the power system stabilizer output at shaft torsional frequencies, said means including a composite band-reject filter including a plurality of biquad filter elements connected in series, wherein each filter element has a tuned frequency at or near a different shaft torsional frequency whereby the band-reject filter attenuates the power system stabilizer output within the total bandwidth of shaft torsional frequencies; a composite band-pass filter including a plurality of biquad filter elements connected in series, wherein each filter element has a tuned frequency at or near a different shaft torsional frequency, said composite band-pass filter connected in series with said composite band-reject filter; means for comparing the input to said band-reject filter with the output from said band-pass filter to determine a signal difference whereby if the signal difference exceeds a predetermined amount the power system stabilizer output may be interrupted.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-03-20 | 1981-09-19 | 1982-03-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-03-20 | 1985-09-19 | 1986-03-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-03-20 | 1989-09-19 | 1990-03-21 | $7700.00 | Window Closed / Lapsed |