US4126825A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic current transducer for high voltage transmission lines
Assignee: Electric Power Research Institute
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Filing: 1977-10-25
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Granted: 1978-11-21
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Expires: 1997-10-25
Abstract
Abstract An electronic current transducer for high voltage transmission lines including a fast analog data channel for providing effective relaying information which is stablized by a slow, highly accurate, channel which is insensitive to changes in gain. In addition for dc transmission lines where polarity may reverse, offsetting or biasing allows for bipolar measurement.
Inventors
- 👤 John M. Houston
- 👤 Harry R. Summerhayes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 19:36
CPC Classifications
G; G01; G01R; G01R15/00; G01R15/14; G01R15/18; G01R15/22
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
104 words
Electronic current transformer apparatus for measuring the line current of a high voltage transmission line comprising: an analog fast channel having means for transmitting line current data in continuous form with a relatively wide dynamic range and frequency response but with a relatively unstable gain characteristic; a slow channel in parallel with said fast channel and having means for transmitting line current data in discrete form with a relatively stable gain characteristic but with relatively narrow dynamic range and frequency response, and means for calibrating said fast channel data with said slow channel data to produce a gain stabilized replica of said line current.
Claim 2
Dependent Claim
104 words
Electronic current transformer apparatus for measuring the line current of a high voltage transmission line comprising: an analog fast channel having means for transmitting line current data in continuous form with a relatively wide dynamic range and frequency response but with a relatively unstable gain characteristic; a slow channel in parallel with said fast channel and having means for transmitting line current data in discrete form with a relatively stable gain characteristic but with relatively narrow dynamic range and frequency response, and means for calibrating said fast channel data with said slow channel data to produce a gain stabilized replica of said line current.
Claim 3
Dependent Claim
20 words
Apparatus as in claim 1 where said slow channel includes analog to digital conversion means for producing said discrete data.
Claim 4
Dependent Claim
36 words
Apparatus as in claim 1 where said channels both include a portion at line potential and another portion at ground potential, such portions being linked by fiber optic means respectively transmitting said continuous and discrete data.
Claim 5
Dependent Claim
16 words
Apparatus as in claim 1 where the averaging time constants of each channel are substantially equal.
Claim 6
Dependent Claim
39 words
Apparatus as in claim 1 where said line current is dc and said fast and slow channels include a common input amplifier for sensing said line current together with means for offsetting said sensed line current or predetermined amount.
Claim 7
Dependent Claim
13 words
Apparatus as in claim 5 where said offsetting means includes a Zener diode.
Claim 8
Dependent Claim
19 words
Apparatus as in claim 5 together with another offsetting means included in said calibrating means for removing said offset.
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) | 1981-11-20 | 1982-05-22 | 1982-11-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-11-20 | 1986-05-22 | 1986-11-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-11-20 | 1990-05-22 | 1990-11-21 | $7700.00 | Window Closed / Lapsed |