US3987239A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High voltage dc cables
Assignee: Individual
•
Filing: 1974-07-15
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Granted: 1976-10-19
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Expires: 1994-07-15
Abstract
Abstract This disclosure deals with the minimization of electric stresses and the increase of breakdown-withstanding capabilities in DC insulation systems or conductivity, or conductance and resistance, within the insulation media. The stress is kept at a minimum by arranging the layers of insulations to follow a particular pattern based on conductivity constants of the material at its distance from the conductor.
Inventors
- 👤 Shee-Ming Chen
- 👤 Spyridon Armenis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 11:07
CPC Classifications
H; H01; H01B; H01B7/00; H01B7/02; H01B7/0208
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
103 words
Insulated conductor apparatus having, in combination, successive sections of insulation disposed at successive contiguous distances r from a conductor to which DC voltage is to be applied that electrically stresses the medium, the successive sections being of successively different conductivities σ o following an unsymmetrical conductivity distribution through the insulation and generally having a relatively low, substantially flat region for distances closer to the conductor and increasing steeply to relatively higher values at distances more remote from the conductor in order to minimize electric stress in the medium at all load conditions and flatten the electric stress distribution over said sections, under load.
Claim 2
Dependent Claim
103 words
Insulated conductor apparatus having, in combination, successive sections of insulation disposed at successive contiguous distances r from a conductor to which DC voltage is to be applied that electrically stresses the medium, the successive sections being of successively different conductivities σ o following an unsymmetrical conductivity distribution through the insulation and generally having a relatively low, substantially flat region for distances closer to the conductor and increasing steeply to relatively higher values at distances more remote from the conductor in order to minimize electric stress in the medium at all load conditions and flatten the electric stress distribution over said sections, under load.
Claim 3
Dependent Claim
40 words
Insulated conductor apparatus as claimed in claim 1 and in which said voltage is of the order of tenths and hundreds of DC kilovolts and the said conductivity ratio distribution extends within a range of at least 1 to 10.
Claim 4
Dependent Claim
17 words
Insulated conductor apparatus as claimed in claim 2 and in which said sections are substantially equal-thickness layers.
Claim 5
Dependent Claim
17 words
Insulated conductor apparatus as claimed in claim 2 and in which said sections are of different thicknesses.
Claim 6
Dependent Claim
28 words
Insulated conductor apparatus as claimed in claim 2 and in which said insulation is selected from the group of dielectric materials consisting of solid, liquid and liquid-solid insulators.
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) | 1979-10-19 | 1980-04-19 | 1980-10-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-10-19 | 1984-04-19 | 1984-10-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-10-19 | 1988-04-19 | 1988-10-19 | $7700.00 | Window Closed / Lapsed |