EP0012772A1 - Utilization of a glass-ceramic material as electrical insulator - Google Patents

Utilization of a glass-ceramic material as electrical insulator

Info

Publication number
EP0012772A1
EP0012772A1 EP79901151A EP79901151A EP0012772A1 EP 0012772 A1 EP0012772 A1 EP 0012772A1 EP 79901151 A EP79901151 A EP 79901151A EP 79901151 A EP79901151 A EP 79901151A EP 0012772 A1 EP0012772 A1 EP 0012772A1
Authority
EP
European Patent Office
Prior art keywords
glass
utilization
electrical insulator
weight
ceramic material
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Withdrawn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
EP79901151A
Other languages
German (de)
French (fr)
Inventor
Veikko Orpana
Matti Wisur
Olov WÄRULF
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.)
SSAB Svenskt Stal AB
Original Assignee
SSAB Svenskt Stal AB
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 SSAB Svenskt Stal AB filed Critical SSAB Svenskt Stal AB
Publication of EP0012772A1 publication Critical patent/EP0012772A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C10/00—Devitrified glass ceramics, i.e. glass ceramics having a crystalline phase dispersed in a glassy phase and constituting at least 50% by weight of the total composition
    • C03C10/0063—Devitrified glass ceramics, i.e. glass ceramics having a crystalline phase dispersed in a glassy phase and constituting at least 50% by weight of the total composition containing waste materials, e.g. slags
    • 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
    • H01B3/02—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of inorganic substances
    • H01B3/08—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of inorganic substances quartz; glass; glass wool; slag wool; vitreous enamels
    • H01B3/087—Chemical composition of glass
    • 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
    • H01B3/02—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of inorganic substances
    • H01B3/12—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of inorganic substances ceramics
    • 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
    • H02G5/00—Installations of bus-bars
    • H02G5/06—Totally-enclosed installations, e.g. in metal casings
    • H02G5/066—Devices for maintaining distance between conductor and enclosure

Abstract

Utilisation d'un materiau de verre-ceramique comme isolateur electrique (16) fabrique a partir de scories de haut fourneau. Le materiau a une teneur de CaO qui depasse ou est egale a 10 pourcent en poids, de preference environ 22 pourcent, et contient aussi des substances dont les valeurs en pourcentages en poids sont les suivantes: 57 % SiO 6 % Al2O3 2,6% MgO 0,2% FeO 0,05% MnO 0,1% TiO2 0,2% S 0,01% P2O5 1,7% Na2O 5,0% K2O L'isolateur electrique constitue un porte-isolateur (16) place, dans un cable ou capsule tubulaire isolee au gaz (10, 12) et destines aux courants de haute tension.Use of a glass-ceramic material as an electrical insulator (16) made from blast furnace slag. The material has a CaO content which exceeds or is equal to 10 percent by weight, preferably about 22 percent, and also contains substances the values of which in percentages by weight are as follows: 57% SiO 6% Al2O3 2.6% MgO 0.2% FeO 0.05% MnO 0.1% TiO2 0.2% S 0.01% P2O5 1.7% Na2O 5.0% K2O The electrical isolator is a place-holder (16), in a cable or tubular capsule insulated with gas (10, 12) and intended for high voltage currents.

Description

Utilization of a glass-ceramic material as electrical insulator .
The present invention relates to utilization as electrical insulator of a glass-ceramic material made from blast furnace slag.
It is desirable that an underground tube cable generally has an effective service length of at least 50 to 100 years, and to realize this aim v e ry high demands must be put on all details forming part of the cable, i.a. the required insulators which normally will not be replaced in the cable during the said period of time because of the highly complicated working moments associated with such a replacement. Therefore, in order to satisfy the high demands the insulators must have the following properties:
- excellent electrical insulating capacity,
- excellent mechanical strength,
- excellent shape permanence,
- excellent corrosion resistance,
- excellent resistance against ageing, and
- excellent resistance against carbonizing.
One of the reasons why underground tube cables have not yet been used to any greater extent as an alternative to conventional overhead power transmission lines is that the costs of manufacture are relatively high, which i.a. resides therein that there are no cheap insulators which to a desirable extent satisfy all abovestated demands.
Hitherto, the insulators have been made mainly from ceramic materials such as porcelain, of glass and of various epoxy compositions. The insulators consisting of epoxy material have proved to be those which are best suited for utilization in tube cables and tube capsules. Such insulators of epoxy material are manufactured by moulding, but the manufacturing process is highly complicated.
The high costs are also the sole overshading reason why insulators of conventional glass-ceramic material have not at all been utilized in connection with underground tube cables and tube capsules in spite thereof that this material has proved to possess the desired material pro- perties.
The main object of the invention is to provide an electrical insulator which satisfies the demands set forth in the introductory part of this description, especial regard being taken to the requirement of resistance against ageing, simultaneously as the insulator is cheap to manufacture. This is rendered possible, according to the invention, by utilization as electrical insulator of a glass- ceramic material obtained from blast furnace slag, said glass-ceramic material having a content of CaO exceeding or equalling 10 per cent by weight, and preferably amounting to approximately 22 per cent by weight, the electrical insulator forming a pin insulator in a gas-insulated tube cable or tube capsule intended for high voltage. Glass- ceramic material or so-called glass-ceramics of the stated kind have proved to satisfy the aforestated demands on insulator material equally well as conventional glass- ceramic materials having a lower content of CaO and . produced from molten glass. As a starting material for glass-ceramic materials intended for insulators, there is thus utilized extremely cheap so-called low-grade blast furnace slag which is intermixed with a suitable quantity, determinable in advance, of silica, Si02, and treated in a controlled process utilizing high temperatur and high pressure. A material produced in this way and known under the denomination "Slaggsital" has the fol lowing particu lars:
- weight by volume 2.6 - 2.75 gs/cm3
- modulus of elasticity 0.75- 106 - 1.1-106
- bending transverse strength 650 - 1200 kgs/cm2
- compressive strength 4500 - 6000 kgs/cm2
- specific impact value (V-notch value) 2.8 4.0 kgcms/cm2
- microhardness 600 - 800 kgs/mm2 longitudinal expansion coefficient 72-10 -- 95-10- 7 water absorption 0 %
Heat resistance according to
GO ST 11103-64 test piece
30 x 30 x 4 m s 100 150 °C temperature of deformation under load 900 - 1000 °C ther al conductiv ty at
20°C Cal/m, t, °C 0.9
- melting point 1230 - 1270 °C
- acid-resistance in 96% HO 99.15 - 99.98 %
- dielectric strength in electric field at 50 c.p.s. 40 50 kVs/mm
- tangential angle for dielectric losses at 50 c.p.s 0.07 - 0.0029
- specific electric capacity at 50 c.p.s. 7 -7.7
- electrical resistivity 1.7-10 12 Ohm/cm
Hereinafter two examples are given for a chemical analysis (values in per cent) relating to firstly the said "Slaggsital" material and secondly a glass-ceramic material of conventional type which at present is utilized for insulators.
In the Chalmers University of Technology the dielectric strength and the running spark limit have been compared for the "Slaggsital" material and epoxy materials containing various fillers. The tests were carried out in an atmosphere of sulfur hexafluoride, SF6, and evidenced that the "Slaggsital" material was a material equivalent to the epoxy material with regard to utilization in insulators. In endurance tests insulators made of porcelain, epoxy material and glass-ceramic material were, in addition, while kept under voltage, subjected to an aggressive coastal atmosphere. The glass-ceramic insulator solely remained entirely unattacked by corrosion and showed to possess extremely high resistance against ageing, which indicates that this insulator is especially well suited for utilization in underground tube cables and tube capsules.
The above-mentioned "Slaggsital" material has earlier been produced mainly in the shape of plates and discs and has been utilized as covering material in the building industry and as grinding material in the mining industry and the iron and steel industry and in the coal industry and also as acid-proof lining in the chemical industry.
With reference to the accompanying drawing, there will now be described a tube cable containing insulators of the type envisaged by the invention.
Figure 1 is a side view of a tube cable section which is partly cut up for the purpose of improved illustration
Figure 2 is a sectional view on an enlarged scale of the tube cable shown in Figure 1.
The tube cable consists of a sleeve which may be composed of an exterior part 10 and a shielding interior part 12. Disposed within the sleeve are three tubular conductors 14 of aluminium for three-phase operation which are applied symmetrically with a spacing from one another and the encasing sleeve, pin insulators 16 constructed in accordance with the principles of the invention and disposed in spaced relationship along the conductor units serving as spacing members. The ends of the cable section are closed by insulators also made according to the invention in the shape of end discs 18. The prefabricated tube cable sections can already in connection with the fabrication be filled with insulating medium up to operation pressure. When joining the sections together in the ground a minor quantity only of insulating medium need to be added. Alternately, all insulating medium may, of course, be supplied in one operation in connection with the mounting of the tube cable.
The pin insulators 16 are directly secured onto the cable sleeve or (not shown), they may be mounted on a ring member which is inserted into the said sleeve. The insulating medium between the conductors 14 an t e conductors and the sleeve 10, 12 may consist of e.g. sulfur hexafloride, SF6, or gaseous nitrogen, N2, or a mixture of said gases. Oil may also be used in some cases.

Claims

1. Utilization as electrical insulator of a glass-cerami material made from blast furnace slag, c h a r a c t e r i z e d by the glass-ceramic material having a content of CaO exceeding or equalling 10 per cent by weight, preferably 22 per cent by weight, and in addition containing the following substances with the approximative values in per cent by weight stated hereinafter:
and the electrical insulator forming a pin insulator in a gas-insulated tube cable or tube capsule intended for high voltage.
2. Utilization according to claim 1, c h a r a c t e r i z e d by the insulating gas consisting of sulfur hexafluoride, SF6.
3. Utilization according to claim l, c h a r a c t e r i z e d by the insulating gas consisting of a gas mixture containing nitrogen and sulfur hexafluoride.
EP79901151A 1978-03-10 1979-10-09 Utilization of a glass-ceramic material as electrical insulator Withdrawn EP0012772A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE7802801A SE7802801L (en) 1978-03-10 1978-03-10 ELECTRICAL INSULATOR
SE7802801 1978-03-10

Publications (1)

Publication Number Publication Date
EP0012772A1 true EP0012772A1 (en) 1980-07-09

Family

ID=20334282

Family Applications (1)

Application Number Title Priority Date Filing Date
EP79901151A Withdrawn EP0012772A1 (en) 1978-03-10 1979-10-09 Utilization of a glass-ceramic material as electrical insulator

Country Status (5)

Country Link
EP (1) EP0012772A1 (en)
JP (1) JPS55500150A (en)
DK (1) DK448579A (en)
SE (1) SE7802801L (en)
WO (1) WO1979000737A1 (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4550301A (en) * 1982-02-17 1985-10-29 Raychem Corporation PTC Circuit protection device
US4481498A (en) * 1982-02-17 1984-11-06 Raychem Corporation PTC Circuit protection device
US4542365A (en) * 1982-02-17 1985-09-17 Raychem Corporation PTC Circuit protection device
US4549161A (en) * 1982-02-17 1985-10-22 Raychem Corporation PTC Circuit protection device
CN106517798B (en) * 2016-10-21 2019-05-17 北京科技大学 In utilization, the method that low titanium blast furnace slag prepares devitrified glass

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB140874A (en) * 1919-02-12 1920-04-08 Thomas Frederick Hoare Improvements in or relating to the utilization of slag as a building and other constructional material
US3022180A (en) * 1959-09-23 1962-02-20 Gen Electric Ceramic material and method of making the same
US3006775A (en) * 1959-09-23 1961-10-31 Gen Electric Ceramic material and method of making the same
BE639369A (en) * 1962-10-30
FR1447653A (en) * 1965-09-22 1966-07-29 Zd Glass based on metallurgical slag and process for obtaining crystallized glass parts therefrom
DE1696070C3 (en) * 1968-02-07 1974-03-07 Ordena Trudowowo Krasnowo Snameni Sawod, Awtosteklo, Konstantinowka (Sowjetunion) Thermally devitrifiable glass with a low crystallization temperature that can be produced using blast furnace slag, in particular in the form of a continuous strip, as well as glass ceramic made from this glass

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO7900737A1 *

Also Published As

Publication number Publication date
SE7802801L (en) 1979-09-11
JPS55500150A (en) 1980-03-21
DK448579A (en) 1979-10-24
WO1979000737A1 (en) 1979-10-04

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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

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AK Designated contracting states

Designated state(s): FR

17P Request for examination filed
STAA Information on the status of an ep patent application or granted ep patent

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18D Application deemed to be withdrawn

Effective date: 19810917

RIN1 Information on inventor provided before grant (corrected)

Inventor name: WAERULF, OLOV

Inventor name: ORPANA, VEIKKO

Inventor name: WISUR, MATTI