WO1999008292A1 - Lightning arrestor - Google Patents

Lightning arrestor Download PDF

Info

Publication number
WO1999008292A1
WO1999008292A1 PCT/ZW1998/000012 ZW9800012W WO9908292A1 WO 1999008292 A1 WO1999008292 A1 WO 1999008292A1 ZW 9800012 W ZW9800012 W ZW 9800012W WO 9908292 A1 WO9908292 A1 WO 9908292A1
Authority
WO
WIPO (PCT)
Prior art keywords
cap
arrestor
surge arrestor
surge
mounting
Prior art date
Application number
PCT/ZW1998/000012
Other languages
French (fr)
Inventor
Bryan Michael Risi
Philip Edward Lawrence Risi
Original Assignee
Chengeta, Cuthbert
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 Chengeta, Cuthbert filed Critical Chengeta, Cuthbert
Priority to AU90431/98A priority Critical patent/AU9043198A/en
Publication of WO1999008292A1 publication Critical patent/WO1999008292A1/en

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
    • H01C7/10—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material voltage responsive, i.e. varistors
    • H01C7/12—Overvoltage protection resistors

Definitions

  • This invention relates to lightning arrestors and, more particularly, to a method of indicating failure of a surge arrestor of a lightning arrestor, and to a lightning arrestor having failure indication.
  • Lightning arrestors are commonly used to protect electrical transmission lines against lightning strikes.
  • Prior art lightning arrestors generally comprise an assembly of an elongate surge arrestor and an explosive cap which detonates when a current exceeding a predetermined magnitude passes through the cap. The assembly is clamped into position with one end of the assembly connected to the transmission line, and the other end earthed.
  • a method of indicating failure of a surge arrestor of a lightning arrestor including the steps of: providing a surge arrestor having a cap attached thereto, the cap being frangible when a current of a predetermined magnitude passes through the cap; and mounting the surge arrestor and the cap between a pair of conductive mounting members to cause the surge arrestor and the cap to be retained in position as a result of a combined length of the surge arrestor and the cap, and for destruction of the cap to cause the combined length to be reduced and the surge arrestor to move out of engagement with the mounting members, thereby indicating failure of the surge arrestor.
  • a lightning arrestor comprising: a surge arrestor; a cap which is mounted on an end of the surge arrestor, the cap being frangible when a current of a predetermined magnitude passes through the cap; and a mounting means arranged on the surge arrestor and the cap for mounting the surge arrestor and the cap on an insulator such that destruction of the cap causes the surge arrestor to move into a position indicating failure of the surge arrestor.
  • the cap may include an explosive charge so that detonation occurs when said current passes through the cap.
  • the mounting means may include a first mounting member positioned on the cap.
  • the first mounting member may be pivotally engageable with a complementary mounting formation extending from the insulator.
  • the mounting means may further include a second mounting member, arranged on an opposed end of the surge arrestor.
  • the second mounting member may be releasably engageable with a complementary mounting formation extending from the insulator.
  • the second mounting member may be such that it moves away from its complementary mounting formation when the cap is destroyed, so that the surge arrestor can pivot away from the insulator.
  • the lightning arrestor may include a retaining means fastened between the surge arrestor and the first mounting member so that the surge arrestor is inhibited from falling to the ground.
  • Figure 1 is a side view of a lightning arrestor according to the invention.
  • FIG. 2 is a perspective view of the lightning arrestor of Figure 1.
  • a lightning arrestor is indicated generally by reference numeral (10)
  • the lightning arrestor (10) includes a surge arrestor (12).
  • a cap (14), including an explosive charge, is mounted on a first end (16) of the surge arrestor (12).
  • the explosive charge in the cap (14) is detonated when a current of a predetermined magnitude passes through the cap (14).
  • the lightning arrestor (10) includes a mounting means (18) which is arranged on the surge arrestor (12) and the cap (14) for mounting the surge arrestor (12) and the cap (14) on an insulator (20).
  • the mounting means (18) includes a first mounting member in the form of a rod (22) which is mounted transversely on an end (21) of the cap (14) via a bracket (24).
  • a carrier (26) is mounted on one end (28) of the insulator (20).
  • the carrier (26) defines a pair of spaced, open-ended slots (30).
  • the rod (22) is received in the slots (30) to be pivotal with respect to the carrier (26)
  • the rod (22), the bracket (24) and the carrier (26) are conductive.
  • the mounting means (18) also includes a part-spherical projection (32) extending from a second end (34) of the surge arrestor (12).
  • An opposed end (36) of the insulator (20) has a blade(38) of spring steel extending therefrom. A portion of the blade (38) defines a part-spherical recess (40).
  • a combined length of the surge arrestor (12) and cap (14) is such that, when the rod (22) is received in the slots (30), the surge arrestor (12) and the cap (14) can be pivoted towards the insulator (20) in the direction of an arrow (42) in Figure 1.
  • the insulator (20) has a mounting bracket (46) extending therefrom. In use, the insulator (20) is mounted, via the mounting bracket (46), on a mast (not shown). The insulator (20) is mounted so that, when the surge arrestor (12) is in the position shown in the drawings, the surge arrestor (12) will pivot, under gravity, away from the insulator (20), in the direction of an arrow (48) in Figure 1 should the projection (32) be displaced from the recess (40).
  • a plate (58) extends into the cap (14).
  • the plate (58) is connected to a stud (not shown) which is fastened to the surge arrestor (12).
  • the lightning arrestor (10) includes a retaining means in the form of a nylon cord (not shown) which is looped between openings (not shown) defined in the plate (58) and in the bracket (24). Thus, the surge arrestor (12) is inhibited from falling to the ground.
  • a handling formation (52) extends from the second end (34) of the surge arrestor (12).
  • the handling formation (52) defines a ring (54) and a push bar (56).
  • the handling formation (52) permits a user to replace the lightning arrestor (10) via a suitable elongate tool.
  • a further ring (62) is mounted on the rod (22) further to facilitate replacement of the lightning arrestor (10).
  • the applicant believes that the invention provides a simple and convenient means for indicating failure of a lightning arrestor.

Landscapes

  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Insulators (AREA)

Abstract

A lightning arrestor includes a surge arrestor, a cap which is mounted on an end of the surge arrestor, in line with the surge arrestor, the cap being frangible when a current of a predetermined magnitude passes through the cap, and mounting brackets arranged on the surge arrestor and the cap. The mounting brackets enable the surge arrestor and cap to be mounted on an insulator such that destruction of the cap causes the surge arrestor to move into a position indicating failure of the surge arrestor.

Description

FIELD OF THE INVENTION
This invention relates to lightning arrestors and, more particularly, to a method of indicating failure of a surge arrestor of a lightning arrestor, and to a lightning arrestor having failure indication.
BACKGROUND TO THE INVENTION
Lightning arrestors are commonly used to protect electrical transmission lines against lightning strikes. Prior art lightning arrestors generally comprise an assembly of an elongate surge arrestor and an explosive cap which detonates when a current exceeding a predetermined magnitude passes through the cap. The assembly is clamped into position with one end of the assembly connected to the transmission line, and the other end earthed.
I is difficult to detect when the cap of such a prior art arrestor has detonated, other then by close visual inspection. In order to replace the arrestor the transmission line must first be isolated, thereby disrupting the electrical supply to consumers.
OBJECT OF THE INVENTION
It is an object of this invention to provide a lightning arrestor which will, at least partially, alleviate the abovementioned difficulties.
SUMMARY OF THE INVENTION
According to a first aspect of the invention, there is provided a method of indicating failure of a surge arrestor of a lightning arrestor, the method including the steps of: providing a surge arrestor having a cap attached thereto, the cap being frangible when a current of a predetermined magnitude passes through the cap; and mounting the surge arrestor and the cap between a pair of conductive mounting members to cause the surge arrestor and the cap to be retained in position as a result of a combined length of the surge arrestor and the cap, and for destruction of the cap to cause the combined length to be reduced and the surge arrestor to move out of engagement with the mounting members, thereby indicating failure of the surge arrestor.
According to a second aspect of the invention, there is provided a lightning arrestor, comprising: a surge arrestor; a cap which is mounted on an end of the surge arrestor, the cap being frangible when a current of a predetermined magnitude passes through the cap; and a mounting means arranged on the surge arrestor and the cap for mounting the surge arrestor and the cap on an insulator such that destruction of the cap causes the surge arrestor to move into a position indicating failure of the surge arrestor.
The cap may include an explosive charge so that detonation occurs when said current passes through the cap.
The mounting means may include a first mounting member positioned on the cap. The first mounting member may be pivotally engageable with a complementary mounting formation extending from the insulator.
The mounting means may further include a second mounting member, arranged on an opposed end of the surge arrestor. The second mounting member may be releasably engageable with a complementary mounting formation extending from the insulator.
The second mounting member may be such that it moves away from its complementary mounting formation when the cap is destroyed, so that the surge arrestor can pivot away from the insulator. The lightning arrestor may include a retaining means fastened between the surge arrestor and the first mounting member so that the surge arrestor is inhibited from falling to the ground.
BRIEF DESCRIPTION OF THE DRAWINGS
A preferred embodiment of the invention is described below, by way of example only, and with reference to the accompanying drawings, in which:
Figure 1 is a side view of a lightning arrestor according to the invention; and
Figure 2 is a perspective view of the lightning arrestor of Figure 1.
DETAILED DESCRIPTION OF THE DRAWINGS
Referring to Figures 1 and 2 in which the features of the invention are indicated by like numerals, a lightning arrestor is indicated generally by reference numeral (10)
The lightning arrestor (10) includes a surge arrestor (12). A cap (14), including an explosive charge, is mounted on a first end (16) of the surge arrestor (12). The explosive charge in the cap (14) is detonated when a current of a predetermined magnitude passes through the cap (14).
The lightning arrestor (10) includes a mounting means (18) which is arranged on the surge arrestor (12) and the cap (14) for mounting the surge arrestor (12) and the cap (14) on an insulator (20).
The mounting means (18) includes a first mounting member in the form of a rod (22) which is mounted transversely on an end (21) of the cap (14) via a bracket (24).
A carrier (26) is mounted on one end (28) of the insulator (20). The carrier (26) defines a pair of spaced, open-ended slots (30). The rod (22) is received in the slots (30) to be pivotal with respect to the carrier (26)
The rod (22), the bracket (24) and the carrier (26) are conductive.
The mounting means (18) also includes a part-spherical projection (32) extending from a second end (34) of the surge arrestor (12). An opposed end (36) of the insulator (20) has a blade(38) of spring steel extending therefrom. A portion of the blade (38) defines a part-spherical recess (40).
A combined length of the surge arrestor (12) and cap (14) is such that, when the rod (22) is received in the slots (30), the surge arrestor (12) and the cap (14) can be pivoted towards the insulator (20) in the direction of an arrow (42) in Figure 1.
As the surge arrestor (12) and cap (14) are pivoted into this position, the projection (32) engages the recess (40), clip fashion. A pair of guides (44) is positioned on the blade (38). The second end (34) of the surge arrestor (12) is received between the guides (44).
The insulator (20) has a mounting bracket (46) extending therefrom. In use, the insulator (20) is mounted, via the mounting bracket (46), on a mast (not shown). The insulator (20) is mounted so that, when the surge arrestor (12) is in the position shown in the drawings, the surge arrestor (12) will pivot, under gravity, away from the insulator (20), in the direction of an arrow (48) in Figure 1 should the projection (32) be displaced from the recess (40).
It follows, therefore, that when the current of a predetermined magnitude passes through the cap (14) and detonates the charge in the cap (14), thereby reducing said combined length of the surge arrestor (12) and cap (14), the surge arrestor (12) drops away from the blade (38) and pivots, under gravity, in the direction of the arrow (48).
A plate (58) extends into the cap (14). The plate (58) is connected to a stud (not shown) which is fastened to the surge arrestor (12). Thus, when the cap (14) is destroyed, the plate (58) remains attached to the stud (60). The lightning arrestor (10) includes a retaining means in the form of a nylon cord (not shown) which is looped between openings (not shown) defined in the plate (58) and in the bracket (24). Thus, the surge arrestor (12) is inhibited from falling to the ground.
It is to be appreciated that it will be readily apparent to an observer that the lightning arrestor (10) has failed.
A handling formation (52) extends from the second end (34) of the surge arrestor (12). The handling formation (52) defines a ring (54) and a push bar (56). The handling formation (52) permits a user to replace the lightning arrestor (10) via a suitable elongate tool. A further ring (62) is mounted on the rod (22) further to facilitate replacement of the lightning arrestor (10).
The applicant believes that the invention provides a simple and convenient means for indicating failure of a lightning arrestor.

Claims

1. A method of indicating failure of a surge arrestor of a lightning arrestor, the method including the steps of: providing a surge arrestor having a cap attached thereto, the cap being frangible when a current of a predetermined magnitude passes through the cap; and mounting the surge arrestor and the cap between a pair of conductive mounting members to cause the surge arrestor and the cap to be retained in position as a result of a combined length of the surge arrestor and the cap, and for destruction of the cap to cause the combined length to be reduced and the surge arrestor to move out of engagement with the mounting members, thereby indicating failure of the surge arrestor.
2. A lightning arrestor, comprising: a surge arrestor; a cap which is mounted on an end of the surge arrestor, the cap being frangible when a current of a predetermined magnitude passes through the cap; and a mounting means arranged on the surge arrestor and the cap for mounting the surge arrestor and the cap on an insulator such that destruction of the cap causes the surge arrestor to move into a position indicating failure of the surge arrestor.
3. A lightning arrestor as claimed in claim 2 in which the cap includes an explosive charge which detonates when said current passes through the cap.
4. A lightning arrestor as claimed in either one of claims 2 or 3 in which the mounting means includes a first mounting member positioned on the cap.
5. A lightning arrestor as claimed in claim 4 in which the first mounting member is pivotally engageable with a complementary mounting formation extending from the insulator.
6. A lightning arrestor as claimed in either one of claims 4 or 5 in which the mounting means further includes a second mounting member, arranged on an opposed end of the surge arrestor.
7. A lightning arrestor as claimed in claim 6 in which the second mounting member is releasably engageable with a complementary mounting formation extending from the insulator.
8. A lightning arrestor as claimed in claim 7 in which the second mounting member moves away from its complementary mounting formation when the cap is destroyed so that the surge arrestor can pivot away from the insulator.
9. A lightning arrestor as claimed in any one of claims 4 to 8 which includes a retaining means fastened between the surge arrestor and the first mounting member so that the surge arrestor is inhibited from falling to the ground.
PCT/ZW1998/000012 1997-08-11 1998-08-10 Lightning arrestor WO1999008292A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU90431/98A AU9043198A (en) 1997-08-11 1998-08-10 Lightning arrestor

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ZA97/7155 1997-08-11
ZA977155 1997-08-11

Publications (1)

Publication Number Publication Date
WO1999008292A1 true WO1999008292A1 (en) 1999-02-18

Family

ID=25586529

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/ZW1998/000012 WO1999008292A1 (en) 1997-08-11 1998-08-10 Lightning arrestor

Country Status (2)

Country Link
AU (1) AU9043198A (en)
WO (1) WO1999008292A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20160056004A1 (en) * 2014-08-20 2016-02-25 The Trustees For The Time Being Of The Philip Edward Lawrence Risi Trust Electrical protection assembly

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60218732A (en) * 1984-04-13 1985-11-01 Toshiba Corp Cutting-off device of arrester
US5237482A (en) * 1991-07-10 1993-08-17 Joslyn Corporation High voltage surge arrester with failed surge arrester signaling device
US5444429A (en) * 1993-11-15 1995-08-22 Hubbell Incorporated Electrical assembly with surge arrester and insulator
ZA953621B (en) * 1995-05-05 1996-04-24 Philip Edward Lawrence Risi Drop out lightning arrestor
EP0729209A1 (en) * 1995-02-23 1996-08-28 ABB Management AG Device for indicating a defective state of an electric apparatus, especially a surge arrester

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60218732A (en) * 1984-04-13 1985-11-01 Toshiba Corp Cutting-off device of arrester
US5237482A (en) * 1991-07-10 1993-08-17 Joslyn Corporation High voltage surge arrester with failed surge arrester signaling device
US5444429A (en) * 1993-11-15 1995-08-22 Hubbell Incorporated Electrical assembly with surge arrester and insulator
EP0729209A1 (en) * 1995-02-23 1996-08-28 ABB Management AG Device for indicating a defective state of an electric apparatus, especially a surge arrester
ZA953621B (en) * 1995-05-05 1996-04-24 Philip Edward Lawrence Risi Drop out lightning arrestor

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 010, no. 069 (E - 389) 18 March 1986 (1986-03-18) *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20160056004A1 (en) * 2014-08-20 2016-02-25 The Trustees For The Time Being Of The Philip Edward Lawrence Risi Trust Electrical protection assembly

Also Published As

Publication number Publication date
AU9043198A (en) 1999-03-01

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