Nothing Special   »   [go: up one dir, main page]

GB2474708A - Line-end clamp for earthing an electrical conductor - Google Patents

Line-end clamp for earthing an electrical conductor Download PDF

Info

Publication number
GB2474708A
GB2474708A GB0918694A GB0918694A GB2474708A GB 2474708 A GB2474708 A GB 2474708A GB 0918694 A GB0918694 A GB 0918694A GB 0918694 A GB0918694 A GB 0918694A GB 2474708 A GB2474708 A GB 2474708A
Authority
GB
United Kingdom
Prior art keywords
line
conductor
end clamp
platform
hook formations
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB0918694A
Other versions
GB2474708B (en
GB0918694D0 (en
Inventor
Michael Robert Mundy
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
PBSI Ltd
Original Assignee
PBSI Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by PBSI Ltd filed Critical PBSI Ltd
Priority to GB0918694.1A priority Critical patent/GB2474708B/en
Publication of GB0918694D0 publication Critical patent/GB0918694D0/en
Publication of GB2474708A publication Critical patent/GB2474708A/en
Application granted granted Critical
Publication of GB2474708B publication Critical patent/GB2474708B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R11/00—Individual connecting elements providing two or more spaced connecting locations for conductive members which are, or may be, thereby interconnected, e.g. end pieces for wires or cables supported by the wire or cable and having means for facilitating electrical connection to some other wire, terminal, or conductive member, blocks of binding posts
    • H01R11/11—End pieces or tapping pieces for wires, supported by the wire and for facilitating electrical connection to some other wire, terminal or conductive member
    • H01R11/12—End pieces terminating in an eye, hook, or fork
    • H01R11/14—End pieces terminating in an eye, hook, or fork the hook being adapted for hanging on overhead or other suspended lines, e.g. hot line clamp
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R4/00—Electrically-conductive connections between two or more conductive members in direct contact, i.e. touching one another; Means for effecting or maintaining such contact; Electrically-conductive connections having two or more spaced connecting locations for conductors and using contact members penetrating insulation
    • H01R4/28—Clamped connections, spring connections
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R4/00—Electrically-conductive connections between two or more conductive members in direct contact, i.e. touching one another; Means for effecting or maintaining such contact; Electrically-conductive connections having two or more spaced connecting locations for conductors and using contact members penetrating insulation
    • H01R4/58—Electrically-conductive connections between two or more conductive members in direct contact, i.e. touching one another; Means for effecting or maintaining such contact; Electrically-conductive connections having two or more spaced connecting locations for conductors and using contact members penetrating insulation characterised by the form or material of the contacting members
    • H01R4/64—Connections between or with conductive parts having primarily a non-electric function, e.g. frame, casing, rail
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02G—INSTALLATION OF ELECTRIC CABLES OR LINES, OR OF COMBINED OPTICAL AND ELECTRIC CABLES OR LINES
    • H02G1/00—Methods or apparatus specially adapted for installing, maintaining, repairing or dismantling electric cables or lines
    • H02G1/02—Methods or apparatus specially adapted for installing, maintaining, repairing or dismantling electric cables or lines for overhead lines or cables
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02G—INSTALLATION OF ELECTRIC CABLES OR LINES, OR OF COMBINED OPTICAL AND ELECTRIC CABLES OR LINES
    • H02G7/00—Overhead installations of electric lines or cables
    • H02G7/05—Suspension arrangements or devices for electric cables or lines
    • H02G7/053—Suspension clamps and clips for electric overhead lines not suspended to a supporting wire

Landscapes

  • Suspension Of Electric Lines Or Cables (AREA)

Abstract

A line-end clamp 10 for earthing/grounding an electrical conductor comprises a body 12 on which are mounted two opposed hook formations 14, 22 and a platform 30 disposed in a space between the hook formations 14, 22. The hook formations 14, 22 curve inwardly over the body 12 such that their inner surfaces 18 can engage with a conductor. The line-end clamp 10 further comprises biasing means (e.g, compression spring 32) for biasing the platform 30 towards an extended position in which it can engage with a lower portion of the conductor when an upper portion of the conductor is engaged with the hook formations 14, 22 such that the conductor is gripped between the platform 30 and the inner surfaces 18 of the hook formations 14, 22. The line-end clamp 10 may be of unitary construction and may include a locking mechanism form impeding retraction of the platform 30 from the extended position. The upper surface of the platform 30 may be electrically conductive and insulated and may be flat or profiled to accommodate a profile of the conductor. The hook formations 14, 22 may terminate in retaining ends 16 and the outer surfaces 17 of the hook formations 14, 22 may be sloped.

Description

A CLAMP
Technical Field
The present invention relates to a clamp, and in particular to a clamp for earthing an electrical conductor such as a station busbar, transmission or distribution line, hereinafter referred to as a "conductor", used in an electricity supply and distribution network.
Background to the Invention
It is common for electricity to be distributed from a power station or electricity sub-station to residential premises by means of high-voltage conductors carried by towers, pylons or poles. Typically these conductors carry electricity at voltages between 1 1kV and 400kV. Regular maintenance of substations, transmission lines and distribution lines is essential to ensure the effective operation of the distribution network. Maintenance is typically carried out by technicians who must access the affected substation, tower or pole to effect necessary repairs or maintenance. It will be appreciated that to ensure the safety of the technician the relevant conductor must be isolated from the electricity supply during a maintenance operation. However, additional safety measures are also taken to reduce the risk to a technician in the event that the transmission line being worked on inadvertently becomes live.
One common safety measure is to connect all of the affected conductors to earth prior to commencing work, so that in the event that any of the conductors becomes live the electricity will safely be conducted to earth, rather than passing through the body of the technician. This earthing of the conductors is typically achieved by clamping each of the conductors with a conductive clamp (known as a line-end clamp), with the line-end clamp being electrically connected to a second conductive clamp (known as an earth-end clamp) by means of an electrical cable, the earth-end clamp being clamped to an earthing point so as to establish an electrical connection between the conductor and the earthing point. The earthing point itself is electrically connected to earth potential, and thus by
I
making an electrical connection between the conductors and the earthing point the conductors are electrically connected to earth.
A line-end clamp is typically attached to a conductor by attaching it to a pole and hooking it onto the conductor. As conductors are typically several metres above ground level, the pole must be several metres long, and the length of the pole to which the line-end clamp is attached, combined with the weight of the clamp itself, makes it difficult to manipulate the line-end clamp to hook it onto the conductor, and this process can be time-consuming and frustrating for technicians. Moreover, prolonged manipulation of the poles can lead to injuries. Thus, a need exists for a line-end clamp which can easily be manipulated by a technician to facilitate hooking it onto a conductor.
Summary of Invention
According to a first aspect of the invention, there is provided a line-end clamp comprising a body on which are mounted two opposed hook formations and a platform disposed in a space between the hook formations, the hook formations curving inwardly over the body such that their inner surfaces can engage with a conductor, the line-end clamp further comprising biasing means for biasing the platform towards an extended position in which it can engage with a lower portion of the conductor when an upper portion of the conductor is engaged with the hook formations, such that the conductor is gripped between the platform and the inner surfaces of the hook formations.
The biased platform of the line-end clamp of the present invention facilitates the engagement and disengagement of the clamp from a conductor, as a simple push and twist action can be used both to engage the clamp and to disengage it. Additionally, the biased platform ensures a good connection between the conductor and the clamp, as it ensures that the conductor is securely gripped between the inner surfaces of the hook formations and the platform. Thus, the clamp cannot easily be dislodged by wind or the like, whilst the biased platform is able to accommodate and compensate for any movement caused by arcing that may occur between the clamp and the conductor in use of the clamp.
The biasing means may comprise a compression spring.
The line-end clamp may further comprise a locking mechanism for impeding retraction of the platform from the extended position.
Preferably an upper surface of the platform is substantially flat.
Alternatively the upper surface of the platform may be profiled to accommodate a profile of the conductor.
In some embodiments the platform is electrically conductive, whilst in other embodiments the platform may be electrically insulated.
Outer surfaces of the hook formations may be sloped to assist in engaging the line-end clamp with a conductor, by directing the conductor towards an interior of the clamp.
The hook formations may terminate in retaining ends.
The line-end clamp may be of a unitary construction.
Brief Description of the Drawings
Embodiments of the invention will now be described, strictly by way of example only, with reference to the accompanying drawings, of which: Figure 1 is a view from one side of a line-end clamp; Figure 2 is a cross-sectional view of the line-end clamp of Figure 1; and Figure 3 is a view from above the clamp of Figures 1 and 2.
Description of the Embodiments
Referring first to Figure 1, a line-end clamp is shown generally at 10. The clamp 10 comprises a unitary body 12 which in this example is cast from aluminium, but which may be of another electrically conductive metal, or of a conductive metal alloy.
Aluminium is preferred, however, as it has good electrical conductivity whilst also being relatively lightweight, which reduces the burden on a technician who must attach the line-end clamp to an overhead conductor.
Towards one end of the body 12 there is mounted a first hook formation 14. The first hook formation 14 may be integral with the body 12, or may be attached to the body by welding or the like. The first hook formation 14 extends from an outer edge of the body 12 and curves inwardly over the body 12, terminating in a retaining end 16, which helps to prevent the clamp 10 from accidentally disengaging from a conductor in use. An inner surface of the first hook formation 14 faces a first surface 20 of the body 12. An outer surface 17 of an end part of the first hook formation 14 is sloped to direct a conductor towards an interior of the clamp 10 (i.e. towards the first surface 20 of the body 12), to assist in the engagement of the line-end clamp 10 with the conductor.
Towards an opposite end of the body 12 there is mounted a second hook formation 22 which takes a generally similar form to that of the first hook formation, but is oriented in an opposite sense to the first hook formation 14, as is shown in Figure 3. As with the first hook formation 14, the second hook formation 22 extends from an outer edge of the body 12 and curves inwardly over the body, terminating in a retaining end, with an inner surface of the second hook formation facing a first surface 20 of the body 12. An outer surface of an end part of the second hook formation 22 is sloped to direct a conductor towards an interior of the clamp 10, to assist in the engagement of the line-end clamp 10 with the conductor.
A bore 24 is provided in a generally cenfral region of a lower part 26 of the body 12, as is shown most clearly in Figure 2. A piston 28 is received in the bore 24, and the piston 28 terminates in a generally circular platform 30. In the embodiment illustrated in the accompanying drawings an upper surface of the platform 30 is flat, which is advantageous as the flat upper surface of the platform 30 facilitates the engagement of the upper surface of the platform 30 with a conductor. However, in other embodiments of the line-end clamp 10 the upper surface of the platform 30 may be profiled to accommodate a profile of the conductor to be clamped. For example, the upper surface of the platform 30 my have a curved profile to accommodate a conductor of cylindrical cross-section.
The platform 30 and the piston 28 may be formed of an elecfrically conductive material such as aluminium to improve the electrical connection between the line-end clamp 10 with the conductor. However, certain applications may require that the platform 30 and the piston 28 are electrically isolated from the conductor, so in certain embodiments the platform 30 and/or the piston 28 may be formed of or coated in an electrically insulating material such as a plastics or ceramic material. A compression spring 32 is disposed around the piston 28, with its lower end being retained in the bore 24, and serves to bias the platform 30 towards an extended position, as shown in Figure 2.
The clamp 10 may have a locking mechanism which is operative to lock the piston 28 and the platform 30 in the extended position shown in Figure 2, by impeding retraction of the platform 30 and piston 28, to increase the security of the engagement of the clamp 10 with the conductor. The locking mechanism may be, for example, a collet-based mechanism having a collet which is positioned so as to engage with the piston 28 as it extends under the influence of the compression spring 32 such that arms of the collet constrict around the piston 28, thereby impeding it from being refracted. Alternatively, the locking mechanism may include a twist-operated locking sleeve of a type that will be familiar to those skilled in the art. It will be appreciated that a great many locking mechanisms will be suitable for use in the clamp of the present invention.
An attachment formation 34 is provided on an underside of the lower part 26 of the body 12 to permit the line-end clamp 10 to be attached to a conventional pole to enable the line-end clamp 10 to be engaged with or disengaged from a conductor. An electrical connector 36 is provided on one side of the body 10 to which an electrical cable can be attached to connect the line-end clamp 10 to an earth-end clamp. The electrical connector 36 may take the form of or a simple bolted connection or a specialised bridging clamp.
In use of the line-end clamp 10, one end of an electrical cable is connected to the electrical connector 36, with the other end being attached to an earth-end clamp which is earthed, for example by being clamped to a tower, pylon, earth tape or earth rod. The line-end clamp 10 is then attached to one end of a pole and lifted into the air towards an overhead conductor. The pole is twisted to position the first and second hook formations 14, 22 on either side of the conductor. The pole is then raised further, such that the upper surface of the platform 30 comes into contact with a lower portion of the conductor. The pole is raised further to compress the compression spring 32 and the pole is twisted (in an anticlockwise direction from the orientation shown in Figure 3, although it will be appreciated that the clamp 10 could equally be configured to facilitate application in a clockwise direction for certain applications) to bring the lower surfaces 18 of the first and second hook formations 14, 22 into position above the conductor. The pole is then lowered, or the technician's grip on the pole can simply be relaxed, allowing the compression spring 32 to extend, causing the conductor to be gripped between the upper surface of the platform 30 and the lower surfaces 18 of the first and second hook formations 14, 22, to establish a firm physical and electrical connection between the clamp 10 and the conductor. The pole can then be disconnected from the clamp 10.
To disengage the clamp 10 from a conductor, a pole is raised into the air and attached to the attachment formation 34. The pole is then lifted upwardly against the biasing action of the compression spring 32. This causes the first and second hook formations 14, 22 to disengage from the conductor. When the first and second hook formations 14, 22 have been raised into a position above the conductor the pole is twisted to rotate the clamp 10 into a position in which the conductor is located between the first and second hook formations 14, 22. The pole is then lowered and the line-end clamp 10 can be disconnected from the pole.

Claims (11)

  1. CLAIMS1. A line-end clamp comprising a body on which are mounted two opposed hook formations and a platform disposed in a space between the hook formations, the hook formations curving inwardly over the body such that their inner surfaces can engage with a conductor, the line-end clamp further comprising biasing means for biasing the platform towards an extended position in which it can engage with a lower portion of the conductor when an upper portion of the conductor is engaged with the hook formations, such that the conductor is gripped between the platform and the inner surfaces of the hook formations.
  2. 2. A line-end clamp according to claim 1 wherein the biasing means comprises a compression spring.
  3. 3. A line-end clamp according to claim 1 or claim 2 further comprising a locking mechanism for impeding retraction of the platform from the extended position.
  4. 4. A line-end clamp according to any one of claims 1 to 3 wherein an upper surface of the platform is substantially flat.
  5. 5. A line-end clamp according to any one of claims 1 to 3 wherein an upper surface of the platform is profiled to accommodate a profile of the conductor.
  6. 6. A line-end clamp according to any one of the preceding claims wherein the platform is electrically conductive
  7. 7. A line-end clamp according to any one of claims 1 to 5 wherein the platform is electrically insulated.
  8. 8. A line-end clamp according to any one of the preceding claims wherein the hook formations terminate in retaining ends.
  9. 9. A line-end clamp according to any one of the preceding claims wherein outer surfaces of the hook formations are sloped.
  10. 10. A line-end clamp according to any one of the preceding claims wherein the line-end clamp is of a unitary construction.
  11. 11. A line-end clamp substantially as hereinbefore described with reference to the accompanying drawings.
GB0918694.1A 2009-10-26 2009-10-26 A clamp Active GB2474708B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB0918694.1A GB2474708B (en) 2009-10-26 2009-10-26 A clamp

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB0918694.1A GB2474708B (en) 2009-10-26 2009-10-26 A clamp

Publications (3)

Publication Number Publication Date
GB0918694D0 GB0918694D0 (en) 2009-12-09
GB2474708A true GB2474708A (en) 2011-04-27
GB2474708B GB2474708B (en) 2014-06-25

Family

ID=41426667

Family Applications (1)

Application Number Title Priority Date Filing Date
GB0918694.1A Active GB2474708B (en) 2009-10-26 2009-10-26 A clamp

Country Status (1)

Country Link
GB (1) GB2474708B (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104184090A (en) * 2014-09-18 2014-12-03 国家电网公司 Short-circuit ground wire suspension device
CN105140662A (en) * 2015-08-13 2015-12-09 国网山东夏津县供电公司 Rapid connection device of grounding line
CN106025601A (en) * 2016-06-15 2016-10-12 国网四川省电力公司宜宾供电公司 Convenient-to-connect safety connection device applied to field of power
CN106129664A (en) * 2016-08-30 2016-11-16 江苏兆邦电力器材有限公司 A kind of Integral earthing wire clamp
CN106450837A (en) * 2016-12-01 2017-02-22 国家电网公司 Power supply clamp
CN106785503A (en) * 2017-01-10 2017-05-31 国家电网公司 Short clip is fixed in a kind of livewire work

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112436468A (en) * 2020-11-13 2021-03-02 贵州电网有限责任公司 Self-locking type drainage wire fixing device
CN114725705B (en) * 2022-04-19 2023-11-28 国网河北省电力有限公司经济技术研究院 Adjustable power transmission line grounding wire hook

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1672477A (en) * 1926-03-08 1928-06-05 Tip S Tool Company Inc Tool for handling high-tension electric wires
US2834950A (en) * 1955-03-16 1958-05-13 Samuel S Houlton Hot line connector
DE1089827B (en) * 1957-09-23 1960-09-29 Josef Maeder Current draw, earthing or short-circuit rod for electrical overhead lines
DE1874844U (en) * 1963-04-27 1963-07-04 Dehn & Soehne EARTH, SHORT-CIRCUIT OR CURRENT CONNECTION TERMINAL FOR OVERHEAD LINES.
GB1174401A (en) * 1965-12-29 1969-12-17 P & B Engineering Company Ltd Improvements in or relating to Electrical Connectors.
CN2188809Y (en) * 1993-06-04 1995-02-01 北京供电局城区供电局 Portable earthing wire
DE102007013440A1 (en) * 2007-03-21 2008-09-25 Klotter, Werner Clamp for medium-voltage system or distribution stations for maintaining and repairing medium-voltage switch, is attached in form of movable clamping jaws and opposite support in geometrical form

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1672477A (en) * 1926-03-08 1928-06-05 Tip S Tool Company Inc Tool for handling high-tension electric wires
US2834950A (en) * 1955-03-16 1958-05-13 Samuel S Houlton Hot line connector
DE1089827B (en) * 1957-09-23 1960-09-29 Josef Maeder Current draw, earthing or short-circuit rod for electrical overhead lines
DE1874844U (en) * 1963-04-27 1963-07-04 Dehn & Soehne EARTH, SHORT-CIRCUIT OR CURRENT CONNECTION TERMINAL FOR OVERHEAD LINES.
GB1174401A (en) * 1965-12-29 1969-12-17 P & B Engineering Company Ltd Improvements in or relating to Electrical Connectors.
CN2188809Y (en) * 1993-06-04 1995-02-01 北京供电局城区供电局 Portable earthing wire
DE102007013440A1 (en) * 2007-03-21 2008-09-25 Klotter, Werner Clamp for medium-voltage system or distribution stations for maintaining and repairing medium-voltage switch, is attached in form of movable clamping jaws and opposite support in geometrical form

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104184090A (en) * 2014-09-18 2014-12-03 国家电网公司 Short-circuit ground wire suspension device
CN105140662A (en) * 2015-08-13 2015-12-09 国网山东夏津县供电公司 Rapid connection device of grounding line
CN106025601A (en) * 2016-06-15 2016-10-12 国网四川省电力公司宜宾供电公司 Convenient-to-connect safety connection device applied to field of power
CN106025601B (en) * 2016-06-15 2018-02-06 国网四川省电力公司宜宾供电公司 A kind of convenient for wiring safe termination applied to power domain
CN106129664A (en) * 2016-08-30 2016-11-16 江苏兆邦电力器材有限公司 A kind of Integral earthing wire clamp
CN106450837A (en) * 2016-12-01 2017-02-22 国家电网公司 Power supply clamp
CN106785503A (en) * 2017-01-10 2017-05-31 国家电网公司 Short clip is fixed in a kind of livewire work

Also Published As

Publication number Publication date
GB2474708B (en) 2014-06-25
GB0918694D0 (en) 2009-12-09

Similar Documents

Publication Publication Date Title
GB2474708A (en) Line-end clamp for earthing an electrical conductor
CN201054394Y (en) Omnipotent ground device
CN101325104A (en) Lightning protection post insulator
CN101378153B (en) Diverter for grounding wire
CN202189912U (en) Overhead transmission line grounding device
KR102027945B1 (en) Grounding wire bracket and grounding method using it
CN201233972Y (en) Multifunctional connecting plug
CN204205093U (en) Electricity testing grounding ring
CN101409386A (en) Multifunctional electric contact
CN102457036A (en) Grounding wire of overhead power transmission line
CN203135324U (en) Frapping tool used for power transmission line maintenance
CN206575086U (en) Insulate turnbuckle plate pulling device
KR102454437B1 (en) Lightning protection function-equipped fixing mechanism for overhead power distribution
CN210439765U (en) Composite insulation circuit angle iron cross arm
CN202839155U (en) Single-hanging-point single-wire-clamp duplex V-shaped composite insulator string for +/-500kV same-tower double-circuit lines
CN209249718U (en) A kind of shutter ground line
CN205544165U (en) Cold -contraction cable terminal
CN201829907U (en) Earth wire of overhead transmission line
CN201946765U (en) Grounding electrode
CN213988443U (en) Insulator structure convenient to assembly
CN206400166U (en) Cable fitting more than a kind of double cable OPGW of transformer station's single pole
CN217824162U (en) Insulated drainage wire prepared from insulated cable and suitable for double drainage strings
CN203180460U (en) Insulating support device of OPGW excess cable support for transmission tower
CN213905780U (en) Interlocking protection device at intelligent high-voltage cable terminal
CN205081393U (en) Electrified insulator chain lifting mechanism

Legal Events

Date Code Title Description
732E Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977)

Free format text: REGISTERED BETWEEN 20180426 AND 20180502