US3581152A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Round protection and detecting for high voltage dc transmission system
Assignee: Individual
•
Filing: 1970-03-16
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Granted: 1971-05-25
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Expires: 1990-03-16
Abstract
Abstract A grounding system for high voltage DC transmission lines which provides protection for and detection of changes in the normal operating mode of the high voltage system. The transmission system has a single connection to the earth, at a first point, all other points remote from the first being insulated from their local earth points. Common ground points are provided for all the equipment of the transmission system in each particular area, and these common ground points are then referenced by way of a return line to the single earth connection. Current sensitive means are provided at the single earth connection and voltage sensitive means are provided at the remote locations to detect fault conditions and, where necessary, to shut down the system.
Inventors
- 👤 Lloyd F Hunt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 20:12
CPC Classifications
H; H02; H02H; H02H7/00; H02H7/26; H02H7/268; H02H3/00; H02H3/16; H02J; H02J3/00; H02J3/36; Y; Y02; Y02E; Y02E60/00; Y02E60/60
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
145 words
In a system for protection and supervision of a high voltage DC transmission system having a positive and a negative line, a single common earth point, insulated local earth point remote from said common earth point, and a ground connection conductor from said remote local earth to said common earth point; first detection means connected between said ground connection conductor and said single common earth point to detect any changes in the normal ground current and to provide automatic response thereto; capacitor means connected between said transmission system and said local earth to ground any alternating current components locally while preventing grounding of any DC current at said local earth point; and second detection means connected across said capacitor means to detect any sustained current components absorbed at said local earth, said second detection means being voltage sensitive to provide automatic response to said components.
Claim 2
Dependent Claim
145 words
In a system for protection and supervision of a high voltage DC transmission system having a positive and a negative line, a single common earth point, insulated local earth point remote from said common earth point, and a ground connection conductor from said remote local earth to said common earth point; first detection means connected between said ground connection conductor and said single common earth point to detect any changes in the normal ground current and to provide automatic response thereto; capacitor means connected between said transmission system and said local earth to ground any alternating current components locally while preventing grounding of any DC current at said local earth point; and second detection means connected across said capacitor means to detect any sustained current components absorbed at said local earth, said second detection means being voltage sensitive to provide automatic response to said components.
Claim 3
Dependent Claim
24 words
The system of claim 1, wherein said first detection means comprises a shunt means feeding two parallel polarized ammeters and two parallel polarized relays.
Claim 4
Dependent Claim
55 words
The system of claim 2, wherein the first of said ammeters records full deflection at full ground current, and the second ammeter reads a fractional percentage of full ground current, said first detection means further including a first switching means in series with said second ammeter for selectively connecting said second ammeter into said system.
Claim 5
Dependent Claim
39 words
The system of claim 3, wherein a first of said relays sounds an alarm upon sensing a small ground current, and the second relay disconnects one of the positive or negative transmission lines when a heavy ground current occurs.
Claim 6
Dependent Claim
25 words
The system of claim 1, wherein said second detection means comprises a variable resistive means feeding two parallel polarized voltmeters and two parallel polarized relays.
Claim 7
Dependent Claim
57 words
The system of claim 5, wherein a first of said voltmeters reads a fractional percentage of any voltage across said capacitor, said percentage being established by said resistive means, switch means for selectively connecting said second voltmeter in parallel with said resistive means, said second voltmeter reading a fractional percentage of the reading of said first voltmeter.
Claim 8
Dependent Claim
48 words
The system of claim 6, wherein a first of said relays is adaptable to sound an alarm upon detection of a small voltage across said resistive means, the second of said polarized relays disconnecting one of said first and second DC transmission lines when a predetermined voltage occurs.
Claim 9
Dependent Claim
26 words
The system of claim 4, wherein said second detection means comprises a variable resistive means feeding two parallel polarized voltmeters and two parallel, voltage-sensitive polarized relays.
Claim 10
Dependent Claim
57 words
The system of claim 8, wherein a first of said voltmeters reads a fractional percentage of any voltage across said capacitor, said percentage being established by said resistive means, switch means for selectively connecting said second voltmeter in parallel with said resistive means, said second voltmeter reading a fractional percentage of the reading of said first voltmeter.
Claim 11
Dependent Claim
50 words
The system of claim 9, wherein the first of said voltage-sensitive relays is adapted to sound an alarm upon detection of a small voltage across said resistive means, the second of said voltage-sensitive polarized relays disconnecting one of said first and second DC transmission lines when a predetermined voltage occurs.
References Cited (Backward Citations)
US3454783A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-05-24 | 1974-11-23 | 1975-05-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-24 | 1978-11-23 | 1979-05-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-24 | 1982-11-23 | 1983-05-25 | $7700.00 | Window Closed / Lapsed |