US5121048A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Feedback control system for static volt ampere reactive compensator with thyristor controlled reactances
Assignee: Electric Power Research Institute
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Filing: 1990-10-29
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Granted: 1992-06-09
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Expires: 2010-10-29
Abstract
Abstract An improved control system for static volt ampere reactance compensator provides for a transformation of the three phases into a two-variable system which thus isolates any common mode in the associated delta. Improved control is provided by utilizing the flux change as an advance indication of a disturbance. Lastly, the two-variable system, as it is inverse transformed into a three variable system, has its phasors rotated to prevent oscillation.
Inventors
- 👤 Einar V. Larsen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 19:05
CPC Classifications
H; H02; H02J; H02J3/00; H02J3/18; H02J3/1821; H02J3/1835; H02J3/1864; Y; Y02; Y02E; Y02E40/00; Y02E40/10; Y10; Y10S; Y10S323/00; Y10S323/91
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
123 words
In a static volt-ampere reactive compensator where thyristor controlled reactances are utilized in a normally electrical configuration having three branches each having a current flowing therein, and where a feed back control system controls the firing angles o the thyristor switches to balance said branch currents, the improvement in the control system comprising: means for measuring in each branch of said delta a direct current component of said current flowing in such branch; means for eliminating a common mode current which may circulate in said delta by transforming said three measured direct currents to a two-current variable system, and means for integrating the two currents of said variable system and inverse transforming them to provide three control signals for controlling said firing angles.
Claim 2
Dependent Claim
123 words
In a static volt-ampere reactive compensator where thyristor controlled reactances are utilized in a normally electrical configuration having three branches each having a current flowing therein, and where a feed back control system controls the firing angles o the thyristor switches to balance said branch currents, the improvement in the control system comprising: means for measuring in each branch of said delta a direct current component of said current flowing in such branch; means for eliminating a common mode current which may circulate in said delta by transforming said three measured direct currents to a two-current variable system, and means for integrating the two currents of said variable system and inverse transforming them to provide three control signals for controlling said firing angles.
Claim 3
Dependent Claim
39 words
In an SVC, as in claim 1 where said means for eliminating said common mode current include means for differencing the direct current components of two different paris of said delta branch currents to form said two-current variable system.
Claim 4
Dependent Claim
33 words
In an SVC, as in claim 1 together with phasor rotation means for rotating the phasors of said delta branch currents to reduce oscillation in said delta by rotating said two-current variable system.
Claim 5
Dependent Claim
50 words
In an SVC having a nominal operating range, as in claim 3 where said SVC has a damping ratio characteristic determined by its operating parameters and where the angle of rotation of said two-current variable system is chosen for the lowest damping ratio of said SVC over the operating range.
Claim 6
Dependent Claim
25 words
In an SVC, as in claim 1 including means for sensing flux change and producing a two-variable signal for interacting with said two-current variable system.
Claim 7
Dependent Claim
39 words
In an SVC, as in claim 5 where said delta branch has a three phase voltage across it and where said flux change sensing means include means for filtering tow of said delta voltages corresponding to said two-current variables.
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) | 1995-06-09 | 1995-12-09 | 1996-06-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-06-09 | 1999-12-09 | 2000-06-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-06-09 | 2003-12-09 | 2004-06-09 | $7700.00 | Window Closed / Lapsed |