US4438386A
Expired / Lapsed
US
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Static VAR generation for transmission line compensation of subsynchronous resonance
Assignee: ASEA BROWN BOVERI Inc
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Filing: 1981-09-10
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Granted: 1984-03-20
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Expires: 2001-09-10
Abstract
Abstract There is provided a static VAR generator having a novel method for controlling subsynchronous resonance by monitoring the frequency of the electrical generating system and controlling subsynchronous resonance by phase-firing thyristor controlled inductance.
Inventors
- 👤 Laszlo Gyugyi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 23:22
CPC Classifications
H; H02; H02J; H02J3/00; H02J3/001; H02J3/0014; H02J3/18; H02J3/1821; H02J3/1835; H02J3/1864; Y; Y02; Y02E; Y02E40/00; Y02E40/10
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
83 words
A static VAR generator and network stabilizer comprising: (a) a reactance means disposed for connection into an AC network; (b) a frequency monitoring means for measuring the period of the network voltage and comparing it to the period of a reference voltage cycle to detect subsynchronous resonance in said AC network; (c) a control means connected to said reactance means and said frequency monitoring means for connection of said reactance means into said AC network to damp subsynchronous resonance in said AC network.
Claim 2
Dependent Claim
83 words
A static VAR generator and network stabilizer comprising: (a) a reactance means disposed for connection into an AC network; (b) a frequency monitoring means for measuring the period of the network voltage and comparing it to the period of a reference voltage cycle to detect subsynchronous resonance in said AC network; (c) a control means connected to said reactance means and said frequency monitoring means for connection of said reactance means into said AC network to damp subsynchronous resonance in said AC network.
Claim 3
Dependent Claim
169 words
A static VAR generator and network stabilizer as recited in claim 1 wherein said frequency monitoring means is further comprised of: (a) a network voltage frequency pulse generator disposed to generate pulses representing the period of the network voltage cycle; (b) a high frequency reference clock pulse generator disposed to generate pulses representing the period of an unmodulated reference terminal voltage for comparison with the AC network voltage; (c) an error pulse generator responsive to deviations in the signals of the network voltage frequency pulse generator and the signals of the high frequency reference clock pulse generatir; (d) an error pulse integrator responsive to the output of the error pulse generator disposed to produce a voltage proportional to the deviations of frequency between the network voltage frequency pulse generator and the high frequency reference clock pulse generator representing subsynchronous resonance; and (e) a firing pulse generator responsive to said error pulse integrator to modulate firing delays of thyristors disposed to insert said reactance means to dampen said subsynchronous resonance.
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) | 1987-03-20 | 1987-09-19 | 1988-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-03-20 | 1991-09-19 | 1992-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-03-20 | 1995-09-19 | 1996-03-20 | $7700.00 | Window Closed / Lapsed |