Patent US4384246A successfully refreshed from Google Patents.
US4384246A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Series-thyristor subsynchronous damper for power generators
Assignee: General Electric Co
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Filing: 1981-01-30
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Granted: 1983-05-17
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Expires: 2001-01-30
Abstract
Abstract A voltage source is connected in series with the neutral secondary winding on a generator step-up transformer through an electrical reactance. A control circuit and a pair of thyristor banks are employed to apply the voltage source to the transformer winding to dampen sybsynchronous resonance currents and to prevent torsional mode vibrations from occurring within the generator.
Inventors
- 👤 Einar V. Larsen
- 👤 Daniel H. Baker
- 👤 Colin E. J. Bowler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 12:59
CPC Classifications
H; H02; H02H; H02H7/00; H02H7/06
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
76 words
In a system comprising a voltage generator having a step-up transformer, a circuit for damping subsynchronous resonance oscillations occurring in voltage generators comprising: a pair of thyristors connected in series with one of the windings of a step-up transformer connected with a voltage generator; an electrical reactor connected in series with a voltage source and with said thyristors for supplying electrical current to said transformer to cancel any subsynchronous resonance current flow to said voltage generator.
Claim 2
Dependent Claim
76 words
In a system comprising a voltage generator having a step-up transformer, a circuit for damping subsynchronous resonance oscillations occurring in voltage generators comprising: a pair of thyristors connected in series with one of the windings of a step-up transformer connected with a voltage generator; an electrical reactor connected in series with a voltage source and with said thyristors for supplying electrical current to said transformer to cancel any subsynchronous resonance current flow to said voltage generator.
Claim 3
Dependent Claim
34 words
The circuit of claim 1 wherein said transformer represents one phase of a three-phase connected generator and wherein corresponding pairs of thyristors are connected within each of the other phases of said three-phase generator.
Claim 4
Dependent Claim
23 words
The circuit of claim 1 further including a varistor element connecting across said thyristors in order to protect said thyristors from overvoltage conditions.
Claim 5
Dependent Claim
24 words
The circuit of claim 1 wherein a cathode of each of said thyristors is connected with an anode of the other of said thryristors.
Claim 6
Dependent Claim
22 words
The circuit of claim 1 further including a control circuit for triggering said thyristors upon the occurrence of said subsynchronous resonance current.
Claim 7
Dependent Claim
34 words
The circuit of claim 5 wherein said control circuit is connected to a gate of each of said thyristors to provide a signal at said gate upon the occurrence of said sybsynchronous resonance current.
Claim 8
Dependent Claim
18 words
The circuit of claim 1 wherein said voltage comprises a tertiary winding on said voltage generator step-up transformer.
Claim 9
Dependent Claim
30 words
The circuit of claim 1 wherein said pair of thyristors is connected between a secondary winding of said voltage generator step-up transformer and a neutral terminal of said step-up transformer.
Claim 10
Dependent Claim
27 words
The circuit of claim 1 wherein the primary windings of one phase of said voltage generator step-up transformer are connected with one phase of said voltage generator.
Claim 11
Dependent Claim
12 words
The circuit of claim 5 wherein said control circuit includes a microprocessor.
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) | 1986-05-16 | 1986-11-15 | 1987-05-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-05-16 | 1990-11-15 | 1991-05-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-05-16 | 1994-11-15 | 1995-05-17 | $7700.00 | Window Closed / Lapsed |