EP0987718A1 - Impregnation compound for electrical cables - Google Patents
Impregnation compound for electrical cables Download PDFInfo
- Publication number
- EP0987718A1 EP0987718A1 EP99401901A EP99401901A EP0987718A1 EP 0987718 A1 EP0987718 A1 EP 0987718A1 EP 99401901 A EP99401901 A EP 99401901A EP 99401901 A EP99401901 A EP 99401901A EP 0987718 A1 EP0987718 A1 EP 0987718A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- weight
- compound
- styrene
- conductor
- insulation
- 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.)
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Classifications
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- 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
- H01B3/20—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances liquids, e.g. oils
- H01B3/22—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances liquids, e.g. oils hydrocarbons
-
- 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
- H01B3/28—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances natural or synthetic rubbers
Definitions
- the present invention relates to an impregnation compound for electrical cables, especially for high voltage DC power cables, with an insulation of a plurality of permeable tapes.
- Such cables of the mass impregnated type i.e. metal sheathed cables insulated with paper which is impregnated with a viscous compound, are also designed for high voltage direct current (HVDC) transmission, underground as well as submarine.
- HVDC high voltage direct current
- an oil based electrical insulation compound comprising mineral oils and an oil soluble polymer being a synthetic hydrocarbonic block-copolymer of polystyrene and synthetic rubber having molecular weights from 50,000 - 1,000,000.
- the parallel PCT WO97/04466 also describes an impregnating compound which has a very steep slope of change of viscosity characteristics, whereby the viscosity being high at temperatures equal and below the maximum cable operating temperature and being low at higher temperatures.
- a second object of the present invention is to decrease the possibility of creation of voids in the compound during thermal cycling of the cable.
- a further object of this invention is to reduce the impregnation temperature and in the following to shorten the manufacturing time and to save production costs.
- the impregnating compound has a high nearly constant viscosity of 200 - 700 Pas up to an operating cable conductor temperature of at least 40°C and a low viscosity of less than 0.1 Pas in a temperature range of about 75° to 130°C.
- the impregnating compound has a high nearly constant viscosity of 300 - 500 Pas up to an operating cable conductor temperature of 70°C and a low viscosity of less than 0.1 Pas in a temperature range of about 95° to 125°C.
- the compound or impregnating mass according to the inventions consists of
- the mineral oil in the compound according to this invention is preferably a hydrogenated naphthenic oil with a boiling point between 250 and 540°C with a viscosity at 40°C between 20 and 300 cSt and containing aromatic hydrocarbons in a range between 25 and 50 % by weight.
- thermoplastic elastomer used according to the present invention is a styrene-ethylen-butylene-styrene (SEBS) elastomer with a molecular weight between 100,00 and 250,000 and a styrene content of 25 - 35 % mass.
- SEBS styrene-ethylen-butylene-styrene
- the present invention relates not only to the impregnating compound or mass described above but also to the cable with an insulation impregnated with this compound/mass.
- the invention relates also to the method for making such cables. With the invention there is obtained a HVDC power cable having the properties mentioned above and extra high effect transfer capacity, in the order of 500 MW and above at a voltage of 350 kV and above.
- FIG. 1 is schematically illustrated a HVDC power cable 1 comprising a central multiwire conductor 2 having a substantially circular cross section.
- At least one insulation layer 3 which encompasses the conductor consists of a plurality of permeable paper tapes wound around the conductor.
- At least one non-permeable sheath 4 having a substantially circular cross section encompasses the insulation layer(s) 3 and an impregnating compound substantially fill all interstices within the conductor, all interstices between individual tape layers and all voids within the tape structure itself.
- Two or more insulated cores can be arranged within the same non-permeable sheath.
- the electrical properties of the cable insulating system depend not only on the type of insulation and the cable manufacturing process, but especially on the choice of the impregnation compound.
- Such a compound to be used for HVDC cables should have a low dielectric loss and the ability to absorb hydrogen gas when subjected to ionic bombardment and moreover it should have a long-term stability.
- This compound is characterized by a low viscosity at 100 - 80°C, i.e. 40 m Pas at 100°C, and a nearly constant viscosity from 55 - 50 and down to 0°C. At 0°C this compound has a viscosity of 450 Pas.
- This impregnating compound/mass has a low viscosity at 125 - 115°C and nearly a constant viscosity from 70 - 60 and down to 0°C.
- the above mentioned impregnating compound E has a low viscosity at 100 - 80°C and a nearly constant viscosity from 50 - 40 and down to 0°C.
- the typically Tan 6 is 0.070, the resistivity ⁇ 2 ⁇ 10 11 and the breakdown 60 kV.
- the gas absorbing quality is high, it is typically 12 - 15 mm 3 /min.
- the relatively constant viscosity of the impregnating mass at the working temperature of the cable decreases the possibility of the creation of voids or bubbles in a most effective way, also in the case of thermal cyclings of the cable.
- the low viscosity before the gel-point reduces the impregnation temperature of the cable essentially and as a result the cable manufacturing time, that means especially the time for impregnation of the cable insulation, can be reduced.
- the compound A has its low viscosity of about 0.05 Pas at about 90°C while the compound B, both regarding the invention, has its low viscosity also of about 0.05 Pas at about 110°C.
- the slope of change or both essential viscosity characteristics (high/low) is steep.
- the NH curve in the Fig. 2 describes another prior art (PCT/WO97/04465) which has a "high” viscosity at about 3,000 Pas and a "low” viscosity of about 0.05 Pas at a temperature of about 60°C. But the slope of change in this case is very steep, from its high level of viscosity the NH curve changes its gradient rapidly. So the compound according to the prior art will not perform the conditions which are necessary to acquire the advantages of the present invention.
Abstract
An impregnation compound for electrical cables, especially for high voltage DC power cables, with an insulation of a plurality of permeable tapes, has a high nearly constant viscosity of 200 - 700 Pas up to an operating cable conductor temperature of at least 40 DEG C and low viscosity of less than 0.1 Pas in a temperature range of about 75 DEG to 130 DEG C. The compound consists of 80-98wt% of a mineral oil, 1-10wt% of a thermoplastic elastomer and 1-10wt% of a gas absorbing agent, especially dibenzyltoluene.
Description
The present invention relates to an impregnation compound for electrical cables,
especially for high voltage DC power cables, with an insulation of a plurality of
permeable tapes.
Such cables of the mass impregnated type, i.e. metal sheathed cables insulated
with paper which is impregnated with a viscous compound, are also designed for
high voltage direct current (HVDC) transmission, underground as well as submarine.
During operation of the cable its insulation is heat cycled when the cable is loaded
and unloaded. During loading the impregnating mass expands as a result of heating
caused by the cable conductor, the cable dielectric, the cable sheath and possibly
by cable armouring losses. When the cable cools down during off-loading the drop
of temperature is the highest in the conductor, so that impregnating mass or
compound will be sucked into it, depleting the surrounding insulation of
mass/compound, creating vacuum bubbles and wholly or at least partly empty
spaces within the insulation. High field strength in the section of the said bubbles
causes discharges inside the cable insulation. As in the case of direct current (DC)
the number of partial discharges (PD) per unit time is several decades lower it
allows the use of the mass-impregnated insulation to much higher electrical
stresses. Nevertheless it is the PD during the cooling of the cable that limits the
maximum transmission of power on such a type of cable.
Other limiting factors concerned with making mass-impregnating cables for higher
voltages are linked to the manufacturing processes. The impregnating procedures
are very time consuming and the process can create zones with a lower content of
mass or impregnating compound. Dissection of cables have confirmed that zones in
the cable insulation are sometimes not fully impregnated. This defines a limit for
energy transmission with known cable insulation.
From the PCT WO98/01869 application an electric device with a conductor
insulation with an open porosity is known whereby this insulation is impregnated
with a dielectric fluid comprising an admixture of a polymer to a hydrocarbon based
fluid. Within a first low temperature range this fluid is said to be in a highly viscous
and elastic state, within a second higher temperature range it is in low viscosity and
in a third limited temperature range the viscosity of the dielectric fluid should be
changed between the low viscosity and the highly viscous state.
In the former PCT WO97/04465 application an oil based electrical insulation
compound is described comprising mineral oils and an oil soluble polymer being a
synthetic hydrocarbonic block-copolymer of polystyrene and synthetic rubber having
molecular weights from 50,000 - 1,000,000.
The parallel PCT WO97/04466 also describes an impregnating compound which
has a very steep slope of change of viscosity characteristics, whereby the viscosity
being high at temperatures equal and below the maximum cable operating
temperature and being low at higher temperatures.
Concerning the problems in DC high voltage cables, first in manufacturing such a
kind of cable and second in keeping the insulation bubble-free to avoid damages in
the respective cable by discharges within the compound/mass impregnated
insulation the above mentioned prior art will not be sufficient to have a "bubble-free"
insulation also with an increasing cable working temperature and to have a faster
production time with a decreasing of the manufacturing costs.
It is therefore one object of this invention to provide an impregnating compound with
excellent dielectric properties like Tan δ, resistivity and breakdown and good
absorbing qualities.
A second object of the present invention is to decrease the possibility of creation of
voids in the compound during thermal cycling of the cable.
A further object of this invention is to reduce the impregnation temperature and in
the following to shorten the manufacturing time and to save production costs.
Therefore according to this invention the impregnating compound has a high nearly
constant viscosity of 200 - 700 Pas up to an operating cable conductor temperature
of at least 40°C and a low viscosity of less than 0.1 Pas in a temperature range of
about 75° to 130°C.
Preferably according to the invention the impregnating compound has a high nearly
constant viscosity of 300 - 500 Pas up to an operating cable conductor temperature
of 70°C and a low viscosity of less than 0.1 Pas in a temperature range of about 95°
to 125°C.
Thus the relatively constant viscosity of the impregnating mass i.e. in the range of 4°
to 55°C as the working temperature of the cable will decrease the possibility of the
creation of voids or bubbles in the cable insulation essentially.
The compound or impregnating mass according to the inventions consists of
- 80 - 98 % by weight of a mineral oil,
- 1 - 10 % by weight of a thermoplastic elastomer and
- 1 - 10 % by weight of gas absorbing agents.
The mineral oil in the compound according to this invention is preferably a
hydrogenated naphthenic oil with a boiling point between 250 and 540°C with a
viscosity at 40°C between 20 and 300 cSt and containing aromatic hydrocarbons in
a range between 25 and 50 % by weight.
The thermoplastic elastomer used according to the present invention is a styrene-ethylen-butylene-styrene
(SEBS) elastomer with a molecular weight between 100,00
and 250,000 and a styrene content of 25 - 35 % mass.
The present invention relates not only to the impregnating compound or mass
described above but also to the cable with an insulation impregnated with this
compound/mass. The invention relates also to the method for making such cables.
With the invention there is obtained a HVDC power cable having the properties
mentioned above and extra high effect transfer capacity, in the order of 500 MW and
above at a voltage of 350 kV and above.
The above mentioned and other features and objects of the present invention will
clearly appear from the following detailed description of embodiments of the
invention taken in conjunction with some detailed examples of compounds and the
drawings, where
- Fig. 1
- illustrates a high-voltage direct current (HVDC) cable and
- Fig. 2
- schematically illustrates the viscosity characteristics of some impregnating compounds.
In Figure 1 is schematically illustrated a HVDC power cable 1 comprising a central
multiwire conductor 2 having a substantially circular cross section. At least one
insulation layer 3 which encompasses the conductor consists of a plurality of
permeable paper tapes wound around the conductor. At least one non-permeable
sheath 4 having a substantially circular cross section encompasses the insulation
layer(s) 3 and an impregnating compound substantially fill all interstices within the
conductor, all interstices between individual tape layers and all voids within the tape
structure itself. Normally there will also be semiconductive layers 5 and 6 over the
conductor 2 and under the metal sheath 4 respectively. Externally there will be
armour and other protectional layers (not shown). Two or more insulated cores can
be arranged within the same non-permeable sheath.
The electrical properties of the cable insulating system depend not only on the type
of insulation and the cable manufacturing process, but especially on the choice of
the impregnation compound. Such a compound to be used for HVDC cables should
have a low dielectric loss and the ability to absorb hydrogen gas when subjected to
ionic bombardment and moreover it should have a long-term stability.
Examples of compounds with essential characteristics to be used according to the
invention are the following:
- 80 - 96 %
- by weight of a hydrogenated naphthenic mineral oil with a boiling point > 330°C and containing about 35 % by weight of aromatic hydrocarbons,
- 2 - 10 %
- by weight of a styrene-ethylen-butylene-styrene-block copolymer with a molecular weight of 150,000 and
- 2 - 10 %
- by weight of an isomeric mixture of dibenzyltoluene.
This compound is characterized by a low viscosity at 100 - 80°C, i.e. 40 m Pas at
100°C, and a nearly constant viscosity from 55 - 50 and down to 0°C. At 0°C this
compound has a viscosity of 450 Pas.
- 85 - 96 %
- by weight of a hydrogenated naphthenic mineral oil with a boiling point > 330°C and containing about 35 % by weight of aromatic hydrocarbons,
- 2 - 5 %
- by weight of a styrene-ethylen-butylene-styrene-block copolymer with a molecular weight of 200,000 and
- 2 - 10 %
- by weight of an isomeric mixture of dibenzyltoluene.
This impregnating compound/mass has a low viscosity at 125 - 115°C and nearly a
constant viscosity from 70 - 60 and down to 0°C.
- 80 - 96 %
- by weight of a hydrogenated naphthenic mineral oil with a boiling point > 330°C and containing about 42 % by weight of aromatic hydrocarbons,
- 2 - 10 %
- by weight of a styrene-ethylen-butylene-styrene-block copolymer with a molecular weight of 150,000 and
- 2 - 10 %
- by weight of an isomeric mixture of dibenzyltoluene.
- 90 - 95 %
- by weight of a hydrogenated naphthenic mineral oil with a boiling point > 330°C and containing about 42 % by weight of aromatic hydrocarbons,
- 2 - 6 %
- by weight of a styrene-ethylen-butylene-styrene-block copolymer with a molecular weight of 200,000 and
- 2 - 4 %
- by weight of an isomeric mixture of dibenzyltoluene.
- 80 - 95 %
- by weight of a hydrogenated naphthenic mineral oil with a boiling point > 250°C and containing about 30 % by weight of aromatic hydrocarbons,
- 3 - 10 %
- by weight of a styrene-ethylen-butylene-styrene-block copolymer with a molecular weight of 200,000 and
- 2 - 10 %
- by weight of an isomeric mixture of dibenzyltoluene.
The above mentioned impregnating compound E has a low viscosity at 100 - 80°C
and a nearly constant viscosity from 50 - 40 and down to 0°C.
The advantages of the above impregnating compounds are essentially the following:
Their dielectric properties are excellent, the typically Tan 6 is 0.070, the resistivity ~
2 · 1011 and the breakdown 60 kV. The gas absorbing quality is high, it is typically 12
- 15 mm3/min.
The relatively constant viscosity of the impregnating mass at the working
temperature of the cable decreases the possibility of the creation of voids or bubbles
in a most effective way, also in the case of thermal cyclings of the cable.
The low viscosity before the gel-point reduces the impregnation temperature of the
cable essentially and as a result the cable manufacturing time, that means
especially the time for impregnation of the cable insulation, can be reduced.
From the above mentioned impregnating compounds A - E according to the
invention the characteristics of the compounds A and B are shown in the Fig. 2. As
to be seen from this Fig. in the range up to at least 40°C the high viscosity of about
500 Pas will be relatively constant in the case of the compound A, while the viscosity
of the compound B of about 450 Pas will be relatively constant up to 65°C. The low
viscosity which is important for the impregnating process insofar as for reducing the
time for impregnation the temperature should be as low as possible with a minimum
of viscosity of the impregnating mass at the same time.
In the Fig. it is shown that the compound A has its low viscosity of about 0.05 Pas at
about 90°C while the compound B, both regarding the invention, has its low viscosity
also of about 0.05 Pas at about 110°C. The slope of change or both essential
viscosity characteristics (high/low) is steep.
Comparing the characteristic figures of the compound A and B according to the
invention with the regularly used (RU) compound starting with a "high" viscosity of
about 150 Pas the "low" viscosity is about 0.6 Pas at a temperature of 80 to 85°C.
The slope of change from the "high" to the "low" viscosity is flat.
The NH curve in the Fig. 2 describes another prior art (PCT/WO97/04465) which
has a "high" viscosity at about 3,000 Pas and a "low" viscosity of about 0.05 Pas at
a temperature of about 60°C. But the slope of change in this case is very steep,
from its high level of viscosity the NH curve changes its gradient rapidly. So the
compound according to the prior art will not perform the conditions which are
necessary to acquire the advantages of the present invention.
Claims (14)
- Impregnation compound for electrical cables, especially for high voltage DC power cables, with an insulation of a plurality of permeable tapes, characterized in that the said compound has a high nearly constant viscosity of 200 - 700 Pas up to an operating cable conductor temperature of at least 40°C and a low viscosity of less than 0.1 Pas in a temperature range of about 75° to 130°C.
- Compound according to claim 1, characterized in that the said compound has a high nearly constant viscosity of 300 - 500 Pas up to an operating cable conductor temperature of 70°C and a low viscosity of less than 0.1 Pas in a temperature range of about 95° to 125°C.
- Compound according to claim 1 or 2, characterized in that said compound consists of
- 80 - 98 %
- by weight of a mineral oil,
- 1 - 10 %
- by weight of a thermoplastic elastomeres and
- 1 - 10 %
- by weight of gas absorbing agents.
- Compound according to claim 3, characterized in that the mineral oil is a hydrogenated naphthenic oil with a boiling point between 250° and 540°C with a viscosity at 40°C between 20 and 300 cSt containing aromatic hydrocarbons in a range between 25 % and 50 % by weight.
- Compound according to claim 3, characterized in that the thermoplastic elastomer is a styrene-ethylen-butylene-styrene (SEBS) elastomer with a molecular weight between 100,00 and 250,000 and a styrene content of 25 - 35 % mass.
- Compound according to claim 3, characterized in that the gas absorbing agent is an isomeric mixture of dibenzyltoluene.
- Compound according to any of the claims 3 to 6, characterized in that the said compound consists of
- 80 -96 %
- by weight of a hydrogenated naphthenic mineral oil with a boiling point > 330°C and containing about 35 % by weight of aromatic hydrocarbons,
- 2 - 10 %
- by weight of a styrene-ethylen-butylene-styrene block copolymer with a molecular weight of 150,000 and
- 2 - 10 %
- by weight of an isomeric mixture of dibenzyltoluene.
- Compound according to any of the claims 3 to 6, characterized in that the said compound consists of
- 85 - 96 %
- by weight of a hydrogenated naphthenic mineral oil with a boiling point > 330°C and containing about 35 % by weight of aromatic hydrocarbons,
- 2 - 5 %
- by weight of a styrene-ethylen-butylene-styrene-block copolymer with a molecular weight of 200,000 and
- 2 - 10 %
- by weight of an isomeric mixture of dibenzyltoluene.
- Compound according to any of the claims 3 to 6, characterized in that the said compound consists of
- 80 - 96 %
- by weight of a hydrogenated naphthenic mineral oil with a boiling point > 330°C and containing about 42 % by weight of aromatic hydrocarbons,
- 2 - 10 %
- by weight of a styrene-ethylen-butylene-styrene-block copolymer with a molecular weight of 150,000 and
- 2 - 10 %
- by weight of an isomeric mixture of dibenzyltoluene.
- Compound according to any of the claims 3 to 6, characterized in that the said compound consists of
- 90 - 95 %
- by weight of a hydrogenated naphthenic mineral oil with a boiling point > 330°C and containing about 42 % by weight of aromatic hydrocarbons,
- 2 - 6 %
- by weight of a styrene-ethylen-butylene-styrene-block copolymer with a molecular weight of 200,000 and
- 2 - 4 %
- by weight of an isomeric mixture of dibenzyltoluene.
- Compound according to any of the claims 3 to 6, characterized in that the said compound consists of
- 80 - 95 %
- by weight of a hydrogenated naphthenic mineral oil with a boiling point > 250°C and containing about 30 % by weight of aromatic hydrocarbons,
- 3 - 10 %
- by weight of a styrene-ethylen-butylene-styrene-block copolymer with a molecular weight of 200,000 and
- 2 - 10 %
- by weight of an isomeric mixture of dibenzyltoluene.
- High voltage DC power cable (1) comprisingat least one conductor (2),at least one insulation layer (3) encompassing the conductor and consisting of a plurality of permeable tapes wound around the conductor,at least one non-permeable sheath (4) encompassing the insulated conductor (2) andan impregnating compound in accordance with the claims 1 - 11 substantially filling all interstices within the conductor, if any, and the insulation system including all interstices between individual tape layers and all voids within the tape structure itself.
- High voltage cable according to claim 1, characterized in that the permeable conductor insulation (3) consists of lapped tapes made from Kraft-paper.
- Method for making a high voltage power cable having one or more conductors, an insulation system including layers of impregnated lapped tapes and outer non-permeable sheaths, including the steps of placing the insulated conductor(s) into a pressurized container for heating, drying and vacuuming the conductor(s) and/or insulation, thereafter filling the conductor(s) and/or the insulation with an impregnating insulated conductor(s), and including the steps of cooling the dry insulated conductor(s) (2, 3) under pressure before impregnating the conductor(s) (2) and/or the cable insulation (3) with a compound in accordance with the claims 1 to 12.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NO984234 | 1998-09-14 | ||
| NO984234A NO984234L (en) | 1998-09-14 | 1998-09-14 | Impregnation material for electric cables |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| EP0987718A1 true EP0987718A1 (en) | 2000-03-22 |
Family
ID=19902405
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP99401901A Withdrawn EP0987718A1 (en) | 1998-09-14 | 1999-07-26 | Impregnation compound for electrical cables |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0987718A1 (en) |
| JP (1) | JP2000090750A (en) |
| NO (1) | NO984234L (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2001093279A2 (en) * | 2000-05-31 | 2001-12-06 | Abb Ab | Insulated electric cable |
| US6824870B2 (en) | 2000-09-28 | 2004-11-30 | Pirelli S.P.A. | Cable with recyclable covering |
| US6908673B2 (en) | 2000-06-28 | 2005-06-21 | Pirelli Cavi E Sistemi S.P.A. | Cable with recyclable covering |
| US7196270B2 (en) | 2003-01-20 | 2007-03-27 | Prysmian Cavi E Sistemi Energia S.R.L. | Cable with recyclable covering layer |
| US7744950B2 (en) | 2000-12-06 | 2010-06-29 | Prysmian Cavi E Sistemi Energia S.R.L. | Process for producing a cable with a recyclable coating comprising a thermoplastic polymer and a dielectric liquid |
| US7884284B2 (en) | 2005-10-25 | 2011-02-08 | Prysmian Cavi E Sistemi Energia S.R.L. | Energy cable comprising a dielectric fluid and a mixture of thermoplastic polymers |
| US7999188B2 (en) | 2007-06-28 | 2011-08-16 | Prysmian S.P.A. | Energy cable |
| EP3967721A1 (en) | 2020-09-10 | 2022-03-16 | Nexans | Impregnating fluid for high voltage paper lapped power cables |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100773695B1 (en) | 2007-02-02 | 2007-11-05 | 엘에스전선 주식회사 | Impregnation method for high voltage direct current cable |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4259540A (en) * | 1978-05-30 | 1981-03-31 | Bell Telephone Laboratories, Incorporated | Filled cables |
| EP0170054A1 (en) * | 1984-07-11 | 1986-02-05 | Siemens Aktiengesellschaft | Insulating oil for electrical devices |
| WO1997004465A1 (en) * | 1995-07-14 | 1997-02-06 | Norsk Hydro A.S | Electrical insulating oil based compound and its use |
-
1998
- 1998-09-14 NO NO984234A patent/NO984234L/en not_active Application Discontinuation
-
1999
- 1999-07-26 EP EP99401901A patent/EP0987718A1/en not_active Withdrawn
- 1999-09-13 JP JP11258845A patent/JP2000090750A/en not_active Withdrawn
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4259540A (en) * | 1978-05-30 | 1981-03-31 | Bell Telephone Laboratories, Incorporated | Filled cables |
| EP0170054A1 (en) * | 1984-07-11 | 1986-02-05 | Siemens Aktiengesellschaft | Insulating oil for electrical devices |
| WO1997004465A1 (en) * | 1995-07-14 | 1997-02-06 | Norsk Hydro A.S | Electrical insulating oil based compound and its use |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2001093279A2 (en) * | 2000-05-31 | 2001-12-06 | Abb Ab | Insulated electric cable |
| WO2001093279A3 (en) * | 2000-05-31 | 2002-06-27 | Abb Ab | Insulated electric cable |
| US6908673B2 (en) | 2000-06-28 | 2005-06-21 | Pirelli Cavi E Sistemi S.P.A. | Cable with recyclable covering |
| US6824870B2 (en) | 2000-09-28 | 2004-11-30 | Pirelli S.P.A. | Cable with recyclable covering |
| US7744950B2 (en) | 2000-12-06 | 2010-06-29 | Prysmian Cavi E Sistemi Energia S.R.L. | Process for producing a cable with a recyclable coating comprising a thermoplastic polymer and a dielectric liquid |
| US7196270B2 (en) | 2003-01-20 | 2007-03-27 | Prysmian Cavi E Sistemi Energia S.R.L. | Cable with recyclable covering layer |
| US7884284B2 (en) | 2005-10-25 | 2011-02-08 | Prysmian Cavi E Sistemi Energia S.R.L. | Energy cable comprising a dielectric fluid and a mixture of thermoplastic polymers |
| US7999188B2 (en) | 2007-06-28 | 2011-08-16 | Prysmian S.P.A. | Energy cable |
| EP3967721A1 (en) | 2020-09-10 | 2022-03-16 | Nexans | Impregnating fluid for high voltage paper lapped power cables |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2000090750A (en) | 2000-03-31 |
| NO984234L (en) | 2000-03-15 |
| NO984234D0 (en) | 1998-09-14 |
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