Patent US5793593A successfully refreshed from Google Patents.
US5793593A
Expired / Lapsed
US
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Method and apparatus using a five-wire network for distribution of electrical power
Assignee: New York State Electric and Gas Corp
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Filing: 1995-10-24
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Granted: 1998-08-11
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Expires: 2015-10-24
Abstract
Abstract The present invention features a method and an apparatus for distributing electrical power from a power source to a distribution transformer, using at least one hot-phase conductor, a neutral conductor and an independent ground conductor. The neutral conductor is connected to the ground conductor at only one point in the distribution system, preferably at or near the power source. Normal imbalance current flows only in the neutral conductor. Return current flow in the earth is eliminated by the single point neutral-to-ground connection. Magnetic field (MF) generation in this power distribution system is thus reduced and stray voltage problems eliminated. In addition, high-impedance faults are easily detected because the only current ever flowing in the ground conductor is fault current. A method is also described for converting existing power distribution systems to the independent ground topology of the present invention.
Inventors
- 👤 Robert G. Reed
- 👤 Leon D. Hall
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 15:20
CPC Classifications
H; H02; H02J; H02J3/00; H02G; H02G3/00; H02G7/00; H02G7/20
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
165 words
A utility-class power distribution system for distributing electrical power from a power source to a distribution transformer utilizing a five-wire system wherein separate neutral and ground conductors are functionally independent of each other, comprising: a) a hot electrical conductor disposed between and connected to said power source and said distribution transformer; b) a neutral conductor disposed between and connected to said power source and said distribution transformer; c) a ground conductor disposed between and connected to said power source and said distribution transformer, said ground conductor being connected to said power source, the earth and said distribution transformer; and d) a direct connection between said neutral conductor and said ground conductor, said connection being the only direct connection between said neutral conductor and said ground conductor, whereby essentially all neutral current between said power source and said distribution transformer flows in said neutral conductor, and essentially no current flows in said ground conductor, except under a fault condition between said hot conductor and the earth.
Claim 2
Dependent Claim
165 words
A utility-class power distribution system for distributing electrical power from a power source to a distribution transformer utilizing a five-wire system wherein separate neutral and ground conductors are functionally independent of each other, comprising: a) a hot electrical conductor disposed between and connected to said power source and said distribution transformer; b) a neutral conductor disposed between and connected to said power source and said distribution transformer; c) a ground conductor disposed between and connected to said power source and said distribution transformer, said ground conductor being connected to said power source, the earth and said distribution transformer; and d) a direct connection between said neutral conductor and said ground conductor, said connection being the only direct connection between said neutral conductor and said ground conductor, whereby essentially all neutral current between said power source and said distribution transformer flows in said neutral conductor, and essentially no current flows in said ground conductor, except under a fault condition between said hot conductor and the earth.
Claim 3
Dependent Claim
38 words
The utility-class power distribution system for distributing electrical power in accordance with claim 1, wherein said one point at which said neutral conductor and said ground conductor are connected via a direct connection is proximate said power source.
Claim 4
Dependent Claim
27 words
The utility-class power distribution system for distributing electrical power in accordance with claim 1, wherein said power source comprises at least one secondary winding of a transformer.
Claim 5
Dependent Claim
19 words
The system for distributing electrical power in accordance with claim 1, wherein said power source comprises an electrical generator.
Claim 6
Dependent Claim
22 words
The system for distributing electrical power in accordance with claim 1, wherein said power source comprises at least one distributed generation source.
Claim 7
Dependent Claim
44 words
The utility-class power distribution system for distributing electrical power in accordance with claim 1, the system further comprising: e) detection means connected to said ground conductor for detecting current flow in said ground conductor and for generating an output signal that is representative thereof.
Claim 8
Dependent Claim
35 words
The utility-class power distribution system for distributing electrical power in accordance with claim 6, the system further comprising: f) means connected to said detection means for clearing a fault in response to said output signal.
Claim 9
Independent Claim
115 words
A method of distributing polyphase electrical power from a power source to a distribution transformer in a utility-class power distribution system, comprising the steps of: a) providing a plurality of hot electrical conductors disposed between said power source and said distribution transformer; b) providing a neutral conductor disposed between said power source and said distribution transformer; c) providing a ground conductor disposed between said power source and said distribution transformer; d) connecting said power source to said distribution transformer via said plurality of hot conductors and said neutral conductor; and e) connecting said ground conductor to said power source, to the earth, and, via a direct connection, to said neutral conductor at only one point.
Claim 10
Independent Claim
115 words
A method of distributing polyphase electrical power from a power source to a distribution transformer in a utility-class power distribution system, comprising the steps of: a) providing a plurality of hot electrical conductors disposed between said power source and said distribution transformer; b) providing a neutral conductor disposed between said power source and said distribution transformer; c) providing a ground conductor disposed between said power source and said distribution transformer; d) connecting said power source to said distribution transformer via said plurality of hot conductors and said neutral conductor; and e) connecting said ground conductor to said power source, to the earth, and, via a direct connection, to said neutral conductor at only one point.
Claim 11
Dependent Claim
50 words
The method of distributing polyphase electrical power from a power source to a distribution transformer in a utility-class power distribution system in accordance with claim 8, wherein said one point at which said neutral conductor and said ground conductor are connected via a direct connection is proximate said power source.
Claim 12
Dependent Claim
35 words
The method of distributing polyphase electrical power from a power source to a distribution transformer in a utility-class power distribution system in accordance with claim 8, wherein said polyphase electrical power is three-phase electrical power.
Claim 13
Dependent Claim
42 words
The method of distributing polyphase electrical power in a utility-class power distribution system in accordance with claim 8, the steps further comprising: f) monitoring current in said ground conductor; and g) providing an output signal that is representative of said monitored current.
Claim 14
Dependent Claim
40 words
The method of distributing polyphase electrical power in a utility-class power distribution system in accordance with claim 11, the steps further comprising: h) actuating an alarm in response to said output signal when said output signal exceeds a predetermined value.
Claim 15
Dependent Claim
40 words
The method of distributing polyphase electrical power in a utility-class power distribution system in accordance with claim 11, the steps further comprising: h) clearing a fault in response to said output signal when said output signal exceeds a predetermined value.
Claim 16
Independent Claim
181 words
A method of converting a conventional, utility-class power distribution system to a system with independent neutral and ground conductors, comprising the steps of: a) connecting a respective ground conductor from a power source to each distribution transformer of a plurality of distribution transformers in said conventional, utility-class power distribution system; b) connecting a respective neutral conductor from a power source to each distribution transformer in said conventional, utility-class power distribution system when said neutral conductor is not already present; c) removing all connections between all neutral conductors of said conventional, utility-class power distribution system and the earth; and d) reconnecting said respective neutral conductors and said respective ground conductors of said conventional, utility-class power distribution system wherein each of the respective neutral conductors and each of the respective ground conductors are connected at only one point, whereby essentially all neutral current between said power source and each of said distribution transformers flows in each of said respective neutral conductors, and essentially no current flows in said respective ground conductors, except under a fault condition between a hot conductor and the earth.
Claim 17
Independent Claim
181 words
A method of converting a conventional, utility-class power distribution system to a system with independent neutral and ground conductors, comprising the steps of: a) connecting a respective ground conductor from a power source to each distribution transformer of a plurality of distribution transformers in said conventional, utility-class power distribution system; b) connecting a respective neutral conductor from a power source to each distribution transformer in said conventional, utility-class power distribution system when said neutral conductor is not already present; c) removing all connections between all neutral conductors of said conventional, utility-class power distribution system and the earth; and d) reconnecting said respective neutral conductors and said respective ground conductors of said conventional, utility-class power distribution system wherein each of the respective neutral conductors and each of the respective ground conductors are connected at only one point, whereby essentially all neutral current between said power source and each of said distribution transformers flows in each of said respective neutral conductors, and essentially no current flows in said respective ground conductors, except under a fault condition between a hot conductor and the earth.
Claim 18
Dependent Claim
29 words
The method of converting a conventional, utility-class power distribution system in accordance with claim 14, further comprising the step of: e) reconfiguring said power source to a wye configuration.
Claim 19
Dependent Claim
34 words
The method of converting a conventional, utility-class power distribution system in accordance with claim 14, further comprising the step of: e) reconfiguring a neutral current-sensing means to sense current in said respective ground conductors.
Claim 20
Dependent Claim
35 words
The method of converting a conventional, utility-class power distribution system in accordance with claim 14, wherein said only one point at which said respective neutral conductor is connected to ground is proximate said power source.
References Cited (Backward Citations)
US1938732A
Cited
US2214134A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-08-10 | 2002-02-09 | 2002-08-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-08-10 | 2006-02-09 | 2006-08-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-08-10 | 2010-02-09 | 2010-08-11 | $7700.00 | Window Closed / Lapsed |