US5117175A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Remote bias voltage setting LTC control system
Assignee: Hubbell Power Systems Inc
•
Filing: 1990-10-16
•
Granted: 1992-05-26
•
Expires: 2010-10-16
Abstract
Abstract In a alternating current power distribution system utilizing load tap changing (LTC) transformers having selectively actuable tap selector switches operable in response to an LTC control, system including circuitry for providing remotely adjustable bias voltage for combining with the LTC control voltage to remotely control any change of the center operating level of the band.
Inventors
- 👤 Robert D. Pettigrew
- 👤 Sanh D. Luong
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 21:04
CPC Classifications
G; G05; G05F; G05F1/00; G05F1/10; G05F1/12; G05F1/14; G05F1/147; G05F1/153; H; H02; H02J; H02J3/00; H02J3/12
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
142 words
In a alternating current power transmission or distribution system utilizing load tap changing (LTC) transformers having selectively actuable tap selector switches, a remote bias voltage setting LTC control system comprising in combination, (a) a load tap changing control having a plurality of signal inputs, (b) means for establishing a voltage band within which an associated transformer must provide an output, (c) means for providing a center voltage level for said band, (d) means for providing a remotely adjustable bias voltage with said center voltage to change the center operating level of said band, (e) a parallel current balancing module and an AC overcurrent relay for enabling paralleling of associated LTC transformers, (f) supervisory control analog and digital access communication means, and (g) means for coupling control pulses through said communication means to control said means for providing said remotely adjustable bias voltage.
Claim 2
Dependent Claim
142 words
In a alternating current power transmission or distribution system utilizing load tap changing (LTC) transformers having selectively actuable tap selector switches, a remote bias voltage setting LTC control system comprising in combination, (a) a load tap changing control having a plurality of signal inputs, (b) means for establishing a voltage band within which an associated transformer must provide an output, (c) means for providing a center voltage level for said band, (d) means for providing a remotely adjustable bias voltage with said center voltage to change the center operating level of said band, (e) a parallel current balancing module and an AC overcurrent relay for enabling paralleling of associated LTC transformers, (f) supervisory control analog and digital access communication means, and (g) means for coupling control pulses through said communication means to control said means for providing said remotely adjustable bias voltage.
Claim 3
Dependent Claim
38 words
Apparatus as in claim 1 further including software programming for obtaining optimum power flow in said distribution system, and a supervisory control analog and digital access communication system for providing control pulses to said adjustable bias voltage means.
Claim 4
Dependent Claim
38 words
Apparatus as in claim 2 wherein said software programming simulates changes of selected voltage outputs from load tap changing transformer and evaluates said changes prior to providing control pulses to said means for providing said adjustable bias voltage.
Claim 5
Dependent Claim
96 words
Apparatus as in claim 1 wherein said load tap changing control includes an RMS to DC converter and motor means for actuating tap changing switches, said voltage defining a center point of said voltage band being coupled as one input to said converter, the output of said converter being coupled to drive said tap changing switches, and further including, (a) an alternating current relay for controlling circulating currents effected by said LTC transformers, and (b) a parallel balancing means for controlling the position of said LTC transformer taps to minimize circulating current in said LTC transformers.
References Cited (Backward Citations)
US2747157A
Cited
US3238442A
Cited
US4323838A
Cited
US4384247A
Cited
US4419619A
Cited
US4413189A
Cited
US4540934A
Cited
US4695737A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-05-26 | 1995-11-25 | 1996-05-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-05-26 | 1999-11-25 | 2000-05-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-05-26 | 2003-11-25 | 2004-05-26 | $7700.00 | Window Closed / Lapsed |