US3829707A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Gas insulated high voltage electrical transmission line with means for damping transients
Assignee: Allis Chalmers Corp
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Filing: 1973-02-09
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Granted: 1974-08-13
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Expires: 1993-02-09
Abstract
Abstract A gas insulated electrical transmission line, such as a high voltage transmission line insulated by SF6 (sulphur hexafluoride) gas, in which the conductor member is enclosed in a grounded metal sheath filled with an insulating gas, and in which the transmission line conductor member is coated for at least part of its length with a thin coating or skin of a material, such as iron, which has a low skin depth in the frequency range of the undesirable electrical transients which it is desired to damp or attenuate. For example, the skin of iron may typically have a radial thickness of 0.01 mm. The inner conductor member to which the coating is applied should be of a material such as aluminum or copper which is a good electrical conductor and which has a large skin depth at the normal power frequency far below the frequency range of the electrical transients which the outer skin is to damp or attenuate.
Inventors
- 👤 H Pflanz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 16:21
CPC Classifications
H; H02; H02G; H02G5/00; H02G5/06; H02G5/063
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
40 words
A high voltage transmission line as defined in claim 1 in which the lower dielectric strength of said intermediate portion is due to lower density of the insulating gas in said intermediate portion than in said first and second portions.
Claim 2
Dependent Claim
58 words
A high voltage transmission line as defined in claim 1 in which the lower dielectric strength of said intermediate portion is obtained by using the same insulating gas density in said intermediate portion as in said first and second portions but providing a smaller internal sheath diameter in said intermediate portion than in said first and second portions.
Claim 3
Dependent Claim
67 words
A high voltage transmission line as defined in claim 1 in which the lower dielectric strength of said intermediate portion is obtained by the combined effect of using together (1) a lower density of insulating gas in said intermediate portion than in said first and second portions; and (2) also using a smaller internal sheath diameter in said intermediate portion than in said first and second portions.
Claim 4
Dependent Claim
33 words
A high voltage transmission line as defined in claim 1 in which said coating material has a low skin depth at the frequency range of the electrical transients which are to be attenuated.
Claim 5
Dependent Claim
45 words
A high voltage transmission line as defined in claim 1 in which said conductor has a large skin depth at normal power frequencies and said coating material has a low skin depth at the frequency range of the electrical transients which are to be attenuated.
Claim 6
Dependent Claim
20 words
A high voltage transmission line as defined in claim 1 in which said coating material has a high permeability characteristic.
Claim 7
Dependent Claim
23 words
A high voltage transmission line as defined in claim 1 in which said conductor is chosen from the group comprising aluminum and copper.
Claim 8
Dependent Claim
17 words
A high voltage transmission line as defined in claim 1 in which said coating material is iron.
Claim 9
Dependent Claim
19 words
A high voltage transmission line as defined in claim 1 in which said insulating gas is SF6 (sulphur hexafluoride).
Claim 10
Dependent Claim
37 words
A high voltage transmission line as defined in claim 1 in which said coating material is chosen from the group comprising: (1) iron; (2) a nickel-iron alloy; (3) lead; (4) tin; (5) fibre metal; (6) foam metal.
Claim 11
Dependent Claim
317 words
A high voltage transmission line for normally transmitting electricity in the power frequency range, said transmission line being adapted to be connected at one end thereof to a sending station and at an opposite end thereof to a receiving station, said transmission line comprising a grounded hollow electrically conductive sheath extending substantially the entire length of said transmission line, an electrical conductor positioned within said sheath in spaced relation to the inner wall surface of said sheath, said conductor having good electrical conductive properties in the power frequency range, said conductor being coated on the outer surface thereof for a first portion of the length of said transmission line which extends a predetermined distance from said one end of said transmission line and for a second portion of the length of said transmission line which extends a predetermined distance from said opposite end of said transmission line with a transient attenuating coating material in the form of a thin coating of a material selected from the group comprising: (1) iron, (2) a nickel-iron alloy, (3) lead, (4) tin, (5) fibre metal, and (6) foam metal, which coating substantially attenuates electrical transients having a frequency or rate of change substantially higher than said power frequency range, said transmission line including an intermediate portion extending from said first portion to said second portion, said electrical conductor not being coated with a transient attenuating coating material along said intermediate portion of said transmission line, and SF6 insulating gas in said sheath between said electrical conductor and the inner surface of said sheath in both said first and second portions and in said intermediate portion, said electrical transmission line having substantially greater insulation and thus higher dielectric strength between said electrical conductor and said sheath in said first and said second portions of the length of said transmission line than in said intermediate portion of the length of said transmission line.
Claim 12
Dependent Claim
40 words
A high voltage transmission line as defined in claim 12 in which the lower dielectric strength of said intermediate portion is due to lower density of the insulating gas in said intermediate portion than in said first and second portions.
Claim 13
Dependent Claim
57 words
A high voltage transmission line as defined in claim 12 in which the lower dielectric strength of said intermediate portion is obtained by using the same insulating gas density in said intermediate portion as in said first and second portions but providing a smaller sheath diameter in said intermediate portion than in said first and second portions.
Claim 14
Dependent Claim
28 words
A high voltage transmission line as defined in claim 1 in which said intermediate portion is of substantially greater length than said first portion or said second portion.
Claim 15
Dependent Claim
28 words
A high voltage transmission line as defined in claim 12 in which said intermediate portion is of substantially greater length than said first portion or said second portion.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-08-12 | 1978-02-11 | 1978-08-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-08-12 | 1982-02-11 | 1982-08-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-08-12 | 1986-02-11 | 1986-08-13 | $7700.00 | Window Closed / Lapsed |