GB2073965A - Surge diverter/arrester - Google Patents

Surge diverter/arrester Download PDF

Info

Publication number
GB2073965A
GB2073965A GB8011609A GB8011609A GB2073965A GB 2073965 A GB2073965 A GB 2073965A GB 8011609 A GB8011609 A GB 8011609A GB 8011609 A GB8011609 A GB 8011609A GB 2073965 A GB2073965 A GB 2073965A
Authority
GB
United Kingdom
Prior art keywords
surge
arrester
heat
electrical
housing
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
GB8011609A
Other versions
GB2073965B (en
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.)
Bowthorpe EMP Ltd
Original Assignee
Bowthorpe EMP 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 Bowthorpe EMP Ltd filed Critical Bowthorpe EMP Ltd
Priority to CY1295A priority Critical patent/CY1295A/en
Priority to GB8011609A priority patent/GB2073965B/en
Publication of GB2073965A publication Critical patent/GB2073965A/en
Application granted granted Critical
Publication of GB2073965B publication Critical patent/GB2073965B/en
Priority to SG238/85A priority patent/SG23885G/en
Priority to HK490/85A priority patent/HK49085A/en
Priority to MY110/86A priority patent/MY8600110A/en
Expired legal-status Critical Current

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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/66—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by liberation of internal stresses, e.g. shrinking of one of the parts to be joined
    • B29C65/68—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by liberation of internal stresses, e.g. shrinking of one of the parts to be joined using auxiliary shrinkable elements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
    • H01T4/00—Overvoltage arresters using spark gaps
    • H01T4/04—Housings
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
    • B29C66/71—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the composition of the plastics material of the parts to be joined
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2031/00—Other particular articles
    • B29L2031/34—Electrical apparatus, e.g. sparking plugs or parts thereof
    • B29L2031/3406—Components, e.g. resistors

Landscapes

  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Mechanical Engineering (AREA)
  • Thermistors And Varistors (AREA)

Abstract

An electrical surge diverter/arrester comprises a non-linear resistor arrangement (1) between end caps (2) formed with terminal posts (3) and with one or more electrically insulating reinforcing rods (6) extending through bores in the resistor and a heat-shrink sleeve (4) serving to secure the assembly together, the sleeve (4) compacting the end caps (2) onto the resistor arrangement (1) for ensuring good electrical connection therebetween. A plurality of sheds (5) can be integral with the sleeve (4) or separate therefrom. The heat shrink material may incorporate an anti-creepage tracking agent. The invention avoids the risk of explosive shattering associated with porcelain housing. <IMAGE>

Description

SPECIFICATION Improvements in electrical surge diverters This invention concerns improvements in electrical surge diverters (also known as surge arresters) as used particularly, though not exclusively, in electrical power distribution and transmission systems for the safe handling of atmospherically induced surges (lightning strikes for instance) and overvoltages caused by switching operations.
As is well known in the surge diverter art and as is described in our British Patent Application No.
7918273 (Serial No. ), surge arresters commonly comprise a non-linear resistor arrangement contained within the bore of a glazed porcelain insulator housing. The non-linear resistor arrangement commonly has comprised a series arrangement of spark gaps and silicon carbide varistor elements and is designed such that, in the event of a voltage surge on a line connected to the arrester, the spark gaps flash over and put an earth fault on the line for the duration of the surge, the power follow current which can flow through the arrester being limited by the series non-linear resistors to a level which can be cleared by the spark gaps.
The porcelain housing places various constraints upon the manufacture of surge arresters. It is conventional to vacuum dry the assembly of the non-linear resistor arrangement with the porcelain housing and to fill the arrester with an inert gas prior to final sealing. It is also conventional, particularly in the case of larger sized, station class diverters but also in the case of smaller distribution type diverters, to provide a pressure-relief diaphragm at one or both ends of the porcelain insulator housing adapted to rupture in the event of an overpressure occurring in the gas filling of the diverter as a result of the expansion of this gas when the diverter operates to divert a current surge to earth. The purpose of these provisions has been to protect the porcelain housing against explosive shattering which otherwise can occur with corresponding risk to life and property.
The cost of the porcelain insulator housing and of the treatments and arrangements necessary to minimise the danger it presents by virtue of its risk of explosive shattering, has conventionally contributed very significantly to the cost of a surge diverter.
The present invention proposes to obviate the use of porcelain insulators as housings for surge arresters. According to the invention, a surge arrester comprises a generally tubular housing formed of a heat-shrink material. Such a surge arrester can accommodate within its housing any type of electrical surge arrester arrangement and, by virtue of the nature of heat-shrink materials which are in themselves well known, is not subject to any explosive shattering problems and so has no need for special rupturable end seals and, in its manufacture, has no need for the evacuation, drying and inert gas filling stages of conventional surge arresters housed in porcelain.Other advantages arise by virtue of the considerable weight saving which arises by use of heat-shrink material in place of porcelain, which reflects in lower mounting bracket costs, lower installation costs, and lower transportation costs.
The heat-shrink material is necessarily a high voltage electrical insulator, capable of withstanding the electrical potential of a lightning strike for example without dielectric breakdown. Such materials are known per se and are available for example from Raychem Limited. One such heat-shrink material is a modified ethylene propylene polymer preferably incorporating an anti-creepage tracking agent.
An exemplary embodiment of the invention is illustrated in the accompanying drawing and will be described hereinafter in order that the invention might be clearly understood.
In the drawing, details of the non-linear resistor assembly 1 are not shown. This assembly can be of any appropriate form such as the conventional series arrangement of spark gaps and silicon carbide resistors for example or an alternative arrangement comprising zinc oxide varistors. End caps 2 formed with terminal posts 3 are provided at each end of the non-linear resistor arrangement 1, and the whole is secured together by means of a sleeve 4 of heatshrink material. The end caps 2 are formed as shown so as to constitute with the heat-shrink sleeve 4 effective end seals for the non-linear resistor arrangement 1 and also so that as the sleeve 4 is shrunk down onto the resistor 1 and end caps 2 combination, the sleeve 4 compacts the end caps 2 onto the resistor arrangement 1 and ensures good electrical connection between the end caps 2 and the resistor 1.Circumferential grooves formed in the end caps 2 ensure that the heat shrink material binds firmly with the end caps 2.
A plurality of sheds 5 are provided. These preferably are formed also of heat-shrink material and can be formed integrally with the sleeve 4 or can be separate therefrom.
One or more electrically insulating reinforcing rods 6 may be passed through bores in the resistor arrangement 1 to augment the rigidity of the finished arrester.
The above-described embodiment of the invention is but one example of a surge arrester constructed in accordance with the invention and, as will be appreciated by those possessed of appropriate skills and knowledge, various modifications and alternatives are possible. For example, a three phase type surge arrester could be constructed in accordance with the invention so as to have three non-linear resistor limbs extending from a common base mounting, each limb constituting an arrester for one particular phase, and with the three limbs housed within a three-part heat-shrink "udder".
1. An electrical surge diverter/arrester comprising a non-linear resistor arrangement within a tubular housing formed of heat-shrink material.
2. An electrical surge diverter/arrester according to claim 1 wherein said heat-shrink material incorporates an agent for inhibiting electrical creepage tracking.
3. An electrical surge diverter/arrester as claimed in claim 1 or 2 wherein said heat-shrink material
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (10)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements in electrical surge diverters This invention concerns improvements in electrical surge diverters (also known as surge arresters) as used particularly, though not exclusively, in electrical power distribution and transmission systems for the safe handling of atmospherically induced surges (lightning strikes for instance) and overvoltages caused by switching operations. As is well known in the surge diverter art and as is described in our British Patent Application No. 7918273 (Serial No. ), surge arresters commonly comprise a non-linear resistor arrangement contained within the bore of a glazed porcelain insulator housing. The non-linear resistor arrangement commonly has comprised a series arrangement of spark gaps and silicon carbide varistor elements and is designed such that, in the event of a voltage surge on a line connected to the arrester, the spark gaps flash over and put an earth fault on the line for the duration of the surge, the power follow current which can flow through the arrester being limited by the series non-linear resistors to a level which can be cleared by the spark gaps. The porcelain housing places various constraints upon the manufacture of surge arresters. It is conventional to vacuum dry the assembly of the non-linear resistor arrangement with the porcelain housing and to fill the arrester with an inert gas prior to final sealing. It is also conventional, particularly in the case of larger sized, station class diverters but also in the case of smaller distribution type diverters, to provide a pressure-relief diaphragm at one or both ends of the porcelain insulator housing adapted to rupture in the event of an overpressure occurring in the gas filling of the diverter as a result of the expansion of this gas when the diverter operates to divert a current surge to earth. The purpose of these provisions has been to protect the porcelain housing against explosive shattering which otherwise can occur with corresponding risk to life and property. The cost of the porcelain insulator housing and of the treatments and arrangements necessary to minimise the danger it presents by virtue of its risk of explosive shattering, has conventionally contributed very significantly to the cost of a surge diverter. The present invention proposes to obviate the use of porcelain insulators as housings for surge arresters. According to the invention, a surge arrester comprises a generally tubular housing formed of a heat-shrink material. Such a surge arrester can accommodate within its housing any type of electrical surge arrester arrangement and, by virtue of the nature of heat-shrink materials which are in themselves well known, is not subject to any explosive shattering problems and so has no need for special rupturable end seals and, in its manufacture, has no need for the evacuation, drying and inert gas filling stages of conventional surge arresters housed in porcelain.Other advantages arise by virtue of the considerable weight saving which arises by use of heat-shrink material in place of porcelain, which reflects in lower mounting bracket costs, lower installation costs, and lower transportation costs. The heat-shrink material is necessarily a high voltage electrical insulator, capable of withstanding the electrical potential of a lightning strike for example without dielectric breakdown. Such materials are known per se and are available for example from Raychem Limited. One such heat-shrink material is a modified ethylene propylene polymer preferably incorporating an anti-creepage tracking agent. An exemplary embodiment of the invention is illustrated in the accompanying drawing and will be described hereinafter in order that the invention might be clearly understood. In the drawing, details of the non-linear resistor assembly 1 are not shown. This assembly can be of any appropriate form such as the conventional series arrangement of spark gaps and silicon carbide resistors for example or an alternative arrangement comprising zinc oxide varistors. End caps 2 formed with terminal posts 3 are provided at each end of the non-linear resistor arrangement 1, and the whole is secured together by means of a sleeve 4 of heatshrink material. The end caps 2 are formed as shown so as to constitute with the heat-shrink sleeve 4 effective end seals for the non-linear resistor arrangement 1 and also so that as the sleeve 4 is shrunk down onto the resistor 1 and end caps 2 combination, the sleeve 4 compacts the end caps 2 onto the resistor arrangement 1 and ensures good electrical connection between the end caps 2 and the resistor 1.Circumferential grooves formed in the end caps 2 ensure that the heat shrink material binds firmly with the end caps 2. A plurality of sheds 5 are provided. These preferably are formed also of heat-shrink material and can be formed integrally with the sleeve 4 or can be separate therefrom. One or more electrically insulating reinforcing rods 6 may be passed through bores in the resistor arrangement 1 to augment the rigidity of the finished arrester. The above-described embodiment of the invention is but one example of a surge arrester constructed in accordance with the invention and, as will be appreciated by those possessed of appropriate skills and knowledge, various modifications and alternatives are possible. For example, a three phase type surge arrester could be constructed in accordance with the invention so as to have three non-linear resistor limbs extending from a common base mounting, each limb constituting an arrester for one particular phase, and with the three limbs housed within a three-part heat-shrink "udder". CLAIMS
1. An electrical surge diverter/arrester comprising a non-linear resistor arrangement within a tubular housing formed of heat-shrink material.
2. An electrical surge diverter/arrester according to claim 1 wherein said heat-shrink material incorporates an agent for inhibiting electrical creepage tracking.
3. An electrical surge diverter/arrester as claimed in claim 1 or 2 wherein said heat-shrink material comprises a modified ethylene propylene polymer.
4. An electrical surge diverter/arrester as claimed in any of the preceding claims wherein the nonlinear resistor arrangement comprises zinc oxide varistors.
5. An electrical surge diverter/arrester as claimed in any of the preceding claims incorporating one or more electrically insulating reinforcing elements extending through the non-linear resistor arrangement longitudinally of the tubular housing.
6. An electrical surge diverterlarrester as claimed in any of the preceding claims incorporating end caps formed for cooperation with said heat-shrink material housing such that when said housing is heat-shrunk the lateral contraction thereof engages the end caps with the housing and the longitudinal contraction thereof compacts the end caps on to the non-linear resistor arrangement.
7. An electrical surge diverter/arrester as claimed in any of the preceding claims including a number of sheds externally of said housing, the said sheds being formed of heat-shrink material.
8. An electrical surge diverterlarrester as claimed in claim 7 wherein the sheds are formed integrally with the heat-shrink material housing.
9. An electrical surge diverterlarrester as claimed in any of the preceding claims constructed for multi-phase application and comprising a non-linear resistor limb for each phase extending from a common base mounting, each limb constituting a diverter/arrester for one particular phase, and wherein the multiple limbs are housed each within one part of a multiple part heat shrink "udder".
10. An electrical surge diverterlarrester substantially as herein described with reference to the accompanying drawing.
GB8011609A 1980-04-08 1980-04-08 Surge diverter/arrester Expired GB2073965B (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
CY1295A CY1295A (en) 1980-04-08 1980-04-08 Surge diverter/arrester
GB8011609A GB2073965B (en) 1980-04-08 1980-04-08 Surge diverter/arrester
SG238/85A SG23885G (en) 1980-04-08 1985-03-30 Improvements in electrical surge diverters
HK490/85A HK49085A (en) 1980-04-08 1985-06-20 Improvements in electrical surge diverters
MY110/86A MY8600110A (en) 1980-04-08 1986-12-30 Improvements in electrical surge diverters

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB8011609A GB2073965B (en) 1980-04-08 1980-04-08 Surge diverter/arrester

Publications (2)

Publication Number Publication Date
GB2073965A true GB2073965A (en) 1981-10-21
GB2073965B GB2073965B (en) 1984-05-02

Family

ID=10512663

Family Applications (1)

Application Number Title Priority Date Filing Date
GB8011609A Expired GB2073965B (en) 1980-04-08 1980-04-08 Surge diverter/arrester

Country Status (5)

Country Link
CY (1) CY1295A (en)
GB (1) GB2073965B (en)
HK (1) HK49085A (en)
MY (1) MY8600110A (en)
SG (1) SG23885G (en)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3426054A1 (en) * 1984-06-01 1985-12-12 BBC Aktiengesellschaft Brown, Boveri & Cie., Baden, Aargau Overvoltage suppressor
EP0274674A1 (en) * 1986-12-12 1988-07-20 Sediver, Societe Europeenne D'isolateurs En Verre Et Composite Process for manufacturing a lightning arrester, and lightning arrester obtained by this process
EP0280189A1 (en) * 1987-02-23 1988-08-31 Asea Brown Boveri Ab Surge arrester
EP0281945A1 (en) * 1987-03-06 1988-09-14 Sediver, Societe Europeenne D'isolateurs En Verre Et Composite Manufacturing process for a lightning arrester
US4812944A (en) * 1985-11-08 1989-03-14 Raychem Gmbh Electrical equipment
EP0372106A1 (en) * 1988-12-06 1990-06-13 Asea Brown Boveri Ab Surge arrester
GB2188199B (en) * 1986-01-29 1990-12-05 Bowthorpe Emp Ltd Electrical surge arrester/diverter
US5680289A (en) * 1996-06-27 1997-10-21 Raychem Corporation Surge arrester
US5712757A (en) * 1996-06-27 1998-01-27 Raychem Corporation Surge arrester having ridged terminals
US5757604A (en) * 1996-06-27 1998-05-26 Raychem Corporation Surge arrester having grooved and ridged terminals
DE102005007146A1 (en) * 2005-02-11 2006-08-24 Siemens Ag Method for sheathing a varistor block with an electrically insulating sheath and varistor block for a surge arrester
DE19927940B4 (en) * 1999-06-18 2011-08-18 Tridelta Überspannungsableiter GmbH, 07629 Plastic surge arresters in modular design and method for its production

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3426054A1 (en) * 1984-06-01 1985-12-12 BBC Aktiengesellschaft Brown, Boveri & Cie., Baden, Aargau Overvoltage suppressor
US4812944A (en) * 1985-11-08 1989-03-14 Raychem Gmbh Electrical equipment
GB2188199B (en) * 1986-01-29 1990-12-05 Bowthorpe Emp Ltd Electrical surge arrester/diverter
EP0274674A1 (en) * 1986-12-12 1988-07-20 Sediver, Societe Europeenne D'isolateurs En Verre Et Composite Process for manufacturing a lightning arrester, and lightning arrester obtained by this process
US4833438A (en) * 1986-12-12 1989-05-23 Ceraver Method of manufacturing a lightning arrester, and a lightning arrester obtained by the method
US4853670A (en) * 1987-02-23 1989-08-01 Asea Brown Boveri Ab Surge arrester
EP0280189A1 (en) * 1987-02-23 1988-08-31 Asea Brown Boveri Ab Surge arrester
AU595433B2 (en) * 1987-03-06 1990-03-29 Societe Anonyme Dite Ceraver A method of manufacturing a lightning arrester, and a lightning arrester obtained by the method
US4825188A (en) * 1987-03-06 1989-04-25 Ceraver Method of manufacturing a lightning arrester, and a lightning arrester obtained by the method
EP0281945A1 (en) * 1987-03-06 1988-09-14 Sediver, Societe Europeenne D'isolateurs En Verre Et Composite Manufacturing process for a lightning arrester
EP0372106A1 (en) * 1988-12-06 1990-06-13 Asea Brown Boveri Ab Surge arrester
US5680289A (en) * 1996-06-27 1997-10-21 Raychem Corporation Surge arrester
US5712757A (en) * 1996-06-27 1998-01-27 Raychem Corporation Surge arrester having ridged terminals
US5757604A (en) * 1996-06-27 1998-05-26 Raychem Corporation Surge arrester having grooved and ridged terminals
US5818677A (en) * 1996-06-27 1998-10-06 Raychem Corporation Surge arrester having ridged terminals
DE19927940B4 (en) * 1999-06-18 2011-08-18 Tridelta Überspannungsableiter GmbH, 07629 Plastic surge arresters in modular design and method for its production
DE102005007146A1 (en) * 2005-02-11 2006-08-24 Siemens Ag Method for sheathing a varistor block with an electrically insulating sheath and varistor block for a surge arrester

Also Published As

Publication number Publication date
HK49085A (en) 1985-06-28
GB2073965B (en) 1984-05-02
CY1295A (en) 1985-10-18
MY8600110A (en) 1986-12-31
SG23885G (en) 1985-09-13

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Legal Events

Date Code Title Description
732 Registration of transactions, instruments or events in the register (sect. 32/1977)
PE20 Patent expired after termination of 20 years

Effective date: 20000407