EP1360702A1 - Systeme d'isolation, en particulier pour cables d'alimentation electrique - Google Patents

Systeme d'isolation, en particulier pour cables d'alimentation electrique

Info

Publication number
EP1360702A1
EP1360702A1 EP02715385A EP02715385A EP1360702A1 EP 1360702 A1 EP1360702 A1 EP 1360702A1 EP 02715385 A EP02715385 A EP 02715385A EP 02715385 A EP02715385 A EP 02715385A EP 1360702 A1 EP1360702 A1 EP 1360702A1
Authority
EP
European Patent Office
Prior art keywords
composition
insulation system
semiconducting
layer
weight
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.)
Withdrawn
Application number
EP02715385A
Other languages
German (de)
English (en)
Inventor
Esben Str Bech
Inger-Margrete Procida
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.)
NKT Cables AS
Original Assignee
NKT Cables AS
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 NKT Cables AS filed Critical NKT Cables AS
Publication of EP1360702A1 publication Critical patent/EP1360702A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
    • H01B3/18—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances
    • H01B3/30—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes
    • H01B3/44—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes vinyl resins; acrylic resins
    • H01B3/441—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes vinyl resins; acrylic resins from alkenes

Definitions

  • An insulation system in particular for electric power cables
  • the invention relates to an insulation system, in particular for electric power cables.
  • a typical insulated electric power cable generally comprises one or more high potential conductors in a cable core that is surrounded by several layers of polymeric materials including a first semiconducting shield layer, an insulating layer, a second semiconducting layer, a metallic wire or tape shield used as ground phase, and- a protective jacket. Additional layers within this construction such as moisture impervious materials are often incorporated.
  • Polymeric semiconducting shields have been utilized in multilayered power cable construction for many decades. Generally they are used to fabricate solid dielectric power cables rated for voltages higher than 6 kiloVolt
  • the primary purpose of the semiconduc ing stress control shield between the conductor and insulation within an electrical power cable construction is to ensure the long term viability of the primary solid insulation.
  • the use of extruded semiconducting shields essentially eliminates partial discharge within the cable construction at the interface of the conductive and dielectric layers. Longer cable life is also realized through improvement of the conductor shield interfacial smoothness, which minimizes any localized electrical stress concentration. Polymeric conductor shields with improved smoothness have been demonstrated to extend the cable life through accelerated testing.
  • Semiconductors for insulation systems' used for electric power cables are normally produced by mixing a polymer with carbon black. When using 35-40 % of the conductive carbon black, the polymer composition obtains a much higher conductivity.
  • Today polymers such as ethylene vinyl acetate (EVA) , ethylene ethyl acrylate (EEA) and ethylene butyl acrylate (EBA) are preferred in the manufacture of semiconductors. Common for these amorphous polymers are good properties with regard to the high filling of the conductive substance as well as the ability to be extruded. Unfortunately residual polar monomers and other residues are present or develop ' during the compounding, and/or crosslinking can deteriorate the electric properties of the semiconductor.
  • EVA ethylene vinyl acetate
  • ESA ethylene ethyl acrylate
  • EBA ethylene butyl acrylate
  • WO 0079543 discloses an electric cable comprising at least one lead-free polymer insulation, wherein the lead- free polymer insulation is made from a specific elastomer terpolymer EPDM composition.
  • the insulation layer of lead-free polymer material is a replacement of lead- containing insulating polymer compositions used in the art and provides the cable with similar properties with respect to the ability to prevent decay of dielectric strength with time and the formation of water trees.
  • the electric cable may comprise two semiconductive layers with the insulation layer in between the semiconductive layers, wherein all three layers may be based on the same polymer material .
  • the polymer composition used in WO 0079543 as insulating layer and semiconductive layers may result in diffusion residual polar monomers during the compounding and/or crosslinking or diffusion of polar volatile substances into the polymeric insulation, which may deteriorate the electric properties of the semiconductor.
  • One object of the present invention is to provide an alternative insulation system which provides excellent insulating properties.
  • Another object of the present invention is to provide an insulating system where the semiconducting layers and the insulating layer can be extruded to obtain a smooth surface .
  • high power cables cables capable of transmission of above 6 kV or preferably above 32 kV, such as above 72 kV, 150 kV, 400 kV or even more e.g 600 kV.
  • the invention provides an insulating system by which it is possible to optimise the insulating properties due to the compatibility between the semiconducting layers and the insulating layers of the system. Consequently it is possible to produce electric power cables with insulation systems that are long lasting and have excellent insulation properties.
  • One aspect the invention relates to an insulation system in particular for electric power cables, which system comprises at least three adjacent layers constituted by - a first layer of a first semiconducting composition,
  • the semiconducting and the insulation compositions are based on the same polymer material. This means that the major part of the polymeric substance in the polymer matrix of the system is the same polymer.
  • the amount of this polymer constitutes at least 50, preferably at least 60 e.g from 75 to 100 % by weight of the total amount of polymer exclusive fillers in the polymer matrix of the first and the second semiconducting composition and the insulation composition, respectively.
  • the polymer material on which the compositions are based is low density metallocene catalysed polyethylene having a density from 0.825 to 0.920 g/cm 3 .
  • Low density metallocene catalysed polyethylene has excellent properties with regard to electric insulation and has a potential for receiving large amounts of conductive filling material or other filling material due to the low crystallinity of the low density metallocene catalysed polyethylene .
  • the layers of the polymer composition thus comprise at least 50 %, preferably at least 70 %, more preferably at least 80 %, such as more than 90 % by weight of the total amount of polymer of low density metallocene catalysed polyethylene having a density from 0.825 to 0.920 g/cm 3 .
  • the amount of low density metallocene catalysed polyethylene having a density from 0.825 to 0.920 g/cm 3 constitutes at least 50 %, such as at least 60 % or even 80 % by weight of the insulating layer or layers, and the low density metallocene catalysed polyethylene having a density from 0.825 to 0.920 g/cm 3 constitutes at least 30 %, such as at least 40 % or even 60 % by weight of the semiconducting layer or layers.
  • the polyethylene in a preferred embodiment therefore comprises one or more oils in an amount up to 5% by weight, and preferably from 0,2 to 2% by weight .
  • the oil is dielectric oil selected from the group consisting of mineral and synthetic oils, where the synthetic oils are chosen among polyisobutylene, silicon oils and lower molecular PE waxes .
  • the semiconducting compositions comprise carbon black in an amount of 15 to 55 % by weight, preferably in an amount of 30 to 50 % by weight, and even more preferably in an amount of 35 to 45 % by weight.
  • carbon black normally used for polymerbased semiconductors can be used according to the invention. The skilled person is able to select the optimal type of carbon black for a specific purpose and hereby the best semiconductive properties. Thus the possibility of designing an insulation system with the desired semiconductive properties is obtained.
  • the polymer material comprises low density metallocene polyethylene having a density from 0.855 to 0.915 g/cm 3 , more preferably from 0.865 to 0.910 g/cm 3 .
  • low density metallocene polyethylene both the semiconducting compositions and the insulating composition achieve good and stable electric properties.
  • the polyethylene is cross-linked, preferably in a degree of 40-95%, more preferably in a degree of 60-85%.
  • the polyethylene is cross-linked by use of a radical former.
  • the radical former is preferably peroxide, more preferably it is dicumylperoxide .
  • the radical former is added in an amount of preferably 0.2 to 5 % by weight, more preferably 1 to 2 % by weight .
  • the semiconducting compositions have a volume resistance of less than 1000 ohm cm at ambient and working temperature.
  • the best properties of the insulation system are obtained.
  • the ambient and working temperature of the semiconducting compositions is between 0 and 100°C.
  • the invention also relates to the use of the insulation system as described above in medium or high voltage power cables for alternating or direct current (AC or DC) .
  • the invention relates to a method of producing an electric power cable with a polymer-based insulation system comprising the steps of extruding a first layer of a semiconducting composition around a conductor, extruding a layer of an insulating composition around the first layer of semiconducting composition, and extruding a second layer of a semiconducting composition around said layer of an insulating composition wherein the first semiconducting composition, the insulating composition and the second semiconducting composition are based on the same polymer material, which is to be understood in such a way that the major part of the polymeric substance in the polymer matrix of the system is the same polymer.
  • the amount of this polymer constitutes from 50 to 100 %, preferably from 40 to 100
  • the polymer composition of the semiconducting composition and the insulation composition, respectively, should be as described above for the insulation system.
  • the polymer material substantially consists of low density metallocene polyethylene, i.e. at least 95 % by weight of the polymer is low density metallocene polyethylene with a density below 0,920 g/cm 3 .
  • This composition appears to have particularly good electric properties and is very suitable for serving as the polymer basis in an insulation system, in particular for electric power cables.
  • a metallocene PE with a density of about 0.885 and a MFI of 3 g/10 min are melted during mixing in a Haake Reocord at 170 °C for 5 min. 37 % by weight of the PE of Carbon Black (Acetylene Black) is added as well as an antioxidant (Irganox 1010) .
  • the composition is blended at 170 °C for 10 min. at a speed of 50 RPM.
  • the compound is granulated.
  • a second portion of metallocene PE with a density of about 0.885 and a MFI of 3 g/10 min are used for the production of an insulating layer and a power cable with an insulation system composed of a first semiconductive layer made from the PE/carbon black blending, a second insulating layer of the PE and a third semiconductive layer made from the PE/carbon black blending are produced by triple extrusion and cured continuously in a pressure chamber.
  • a cable with a insulation system according to the invention is then obtained.

Landscapes

  • Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Compositions Of Macromolecular Compounds (AREA)

Abstract

Cette invention concerne un système d'isolation destiné en particulier à des câbles d'alimentation électrique. Ce système d'isolation compte au moins trois couches adjacentes constituées par une première couche faite d'un composition semi-conductrice, une deuxième couche de composition isolante, et une troisième couche faite d'une seconde composition semi-conductrice. La première composition semi-conductrice, la deuxième composition isolante et la seconde composition semi-conductrice sont constituées de matériaux comprenant au moins 50 % en poids de la quantité totale de polymère d'un polyéthylène de faible densité catalysé par un métallocène, d'une densité inférieure à 0,920 g/cm3. Le système d'isolation de l'invention marque un progrès en termes de stabilité dans la mesure où la diffusion de substances polaires volatiles se trouve réduite. Est également décrite un procédé de fabrication du système d'isolation.
EP02715385A 2001-01-25 2002-01-24 Systeme d'isolation, en particulier pour cables d'alimentation electrique Withdrawn EP1360702A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DK200100136 2001-01-25
DKPA200100136 2001-01-25
PCT/DK2002/000049 WO2002059909A1 (fr) 2001-01-25 2002-01-24 Systeme d'isolation, en particulier pour cables d'alimentation electrique

Publications (1)

Publication Number Publication Date
EP1360702A1 true EP1360702A1 (fr) 2003-11-12

Family

ID=8160099

Family Applications (1)

Application Number Title Priority Date Filing Date
EP02715385A Withdrawn EP1360702A1 (fr) 2001-01-25 2002-01-24 Systeme d'isolation, en particulier pour cables d'alimentation electrique

Country Status (3)

Country Link
EP (1) EP1360702A1 (fr)
NO (1) NO20033327L (fr)
WO (1) WO2002059909A1 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016097250A1 (fr) * 2014-12-19 2016-06-23 Borealis Ag Composition polymère aux propriétés électriques avantageuses, destinée à une application sur des w&c
EP3173442A1 (fr) * 2015-11-27 2017-05-31 Borealis AG Composition de polyéthylène semiconductrice

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1138733A (en) * 1965-04-19 1969-01-01 Gen Electric Process for preparing curable elastomer composition
NL6903660A (fr) * 1968-03-26 1969-09-30
JPS63301427A (ja) * 1987-06-01 1988-12-08 Fujikura Ltd プラスチツク電力ケ−ブルの製造方法
TW215446B (fr) * 1990-02-23 1993-11-01 Furukawa Electric Co Ltd
CA2116380A1 (fr) * 1993-02-26 1994-08-27 Nof Corporation Composition de polyethylene pour isolants et joints d'alimentation tres haute tension et cables et joints fabriques a partir de cette composition
JPH10116518A (ja) * 1996-10-11 1998-05-06 Fujikura Ltd 直流架橋ポリエチレン絶縁電力ケーブル
PT1192624E (pt) * 1999-06-21 2005-02-28 Pirelli & C Spa Cabo, em particular para transporte ou distribuicao de energia electrica
SE516260C2 (sv) * 1999-07-01 2001-12-10 Borealis Polymers Oy Isolerande komposition för en elektrisk kraftkabel

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO02059909A1 *

Also Published As

Publication number Publication date
NO20033327D0 (no) 2003-07-23
NO20033327L (no) 2003-07-23
WO2002059909A1 (fr) 2002-08-01

Similar Documents

Publication Publication Date Title
EP0935806B1 (fr) Cable resistant aux arbres
EP2092535B1 (fr) Câble électrique
EP0179845B1 (fr) Composition isolante pour cables
JP3682947B2 (ja) 電気絶縁樹脂組成物およびそれを用いた電線・ケーブル
CN111354507B (zh) 耐水树电缆
EP2582751A2 (fr) Isolants contenant des copolymères du styrène
EP1218176B1 (fr) Compose de remplissage a conducteur torsade et cables l'utilisant
EP0970482B1 (fr) Cable resistant a la formation de criques
KR102267280B1 (ko) 극성 유전체 액체를 포함하는 중합체 조성물
US8581102B2 (en) Curable composition for medium and high voltage power cables
JPH04106B2 (fr)
EP1360702A1 (fr) Systeme d'isolation, en particulier pour cables d'alimentation electrique
EP0099640B1 (fr) Câbles isolés à l'aide de polyéthylène réticulé
AU2002224765A1 (en) An insulation system, in particular for electric power cables
KR102354984B1 (ko) 내트래킹성 절연 조성물 및 이를 포함하는 고전압 케이블
EP0152911B1 (fr) Câble électrique isolé
JPH09231839A (ja) 直流ケーブル
JPH08319381A (ja) 電気絶縁樹脂組成物
KR100450184B1 (ko) 전력케이블용 반도전 수밀 펠렛 화합물
JPH07107806B2 (ja) 電力ケ−ブル
JP3414581B2 (ja) 電力ケーブルの半導電層用組成物
KR100291669B1 (ko) 고압 내열 케이블용 반도전 재료
WO2016005791A1 (fr) Câble d'énergie comportant une couche thermoplastique électriquement isolante
JPS61235444A (ja) 半導電性樹脂組成物
JPS6332204B2 (fr)

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20030812

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR

AX Request for extension of the european patent

Extension state: AL LT LV MK RO SI

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN

18W Application withdrawn

Effective date: 20031206