CA2497032C - High-voltage direct current cable insulation and semiconductive shield - Google Patents

High-voltage direct current cable insulation and semiconductive shield Download PDF

Info

Publication number
CA2497032C
CA2497032C CA2497032A CA2497032A CA2497032C CA 2497032 C CA2497032 C CA 2497032C CA 2497032 A CA2497032 A CA 2497032A CA 2497032 A CA2497032 A CA 2497032A CA 2497032 C CA2497032 C CA 2497032C
Authority
CA
Canada
Prior art keywords
less
ethylene
blend
grams
density
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.)
Expired - Fee Related
Application number
CA2497032A
Other languages
French (fr)
Other versions
CA2497032A1 (en
Inventor
Jinder Jow
Alfred Mendelsohn
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.)
Union Carbide Corp
Original Assignee
Union Carbide Chemicals and Plastics Technology LLC
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 Union Carbide Chemicals and Plastics Technology LLC filed Critical Union Carbide Chemicals and Plastics Technology LLC
Publication of CA2497032A1 publication Critical patent/CA2497032A1/en
Application granted granted Critical
Publication of CA2497032C publication Critical patent/CA2497032C/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01BCABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B3/00Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
    • H01B3/18Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances
    • H01B3/30Insulators 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
    • H01B3/44Insulators 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
    • H01B3/441Insulators 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

Abstract

A high-voltage direct current cable insulation is made from a blend which includes an ethylene copolymer, such as ethylene-alpha olefin copolymer, with low crystallinity to reduce physical space charge trapping sites, a polar polymer modifier in an effective amount to enhance local conductivity to leak space charge quickly when local stress is enhanced, and an ion scavenger to stabilize or neutralize the space charge to provide a composition which is an effective high-voltage DC cable insulation. A high-voltage direct current cable semiconductive shield is made from a blend that includes an ethylene copolymer, a carbon black having a low level of ionic species, a polar polymer modifier, and an ion scavenger.

Description

HIGH-VOLTAGE DIRECT CURRENT
CABLE INSULATION AND SEMICONDUCTIVE SHIELD
FIELD OF THE INVENTION
This invention is directed to insulation and a semiconductive shield for power cables. More particularly, this invention is directed to insulation and a semiconductive shield for high-voltage direct current power cables.
s DESCRIPTION OF THE PRIOR ART
Direct Current (DC) power transmission has several advantages over alternating current (AC) power transmission. DC transmission does not have a length limit, permits long-distance submarine cables (>50 km), has good connectivity among different networks/sources (such as windmills), has lower operating costs due to low l0 conductor loss and no power loss, has superior power quality and flow control for system reliabilitylstability, and has higher voltage ratings. Cables insulated with oil/paper insulation have been successfully used for high-voltage direct current (HVDC) applications since 1954. Cables insulated with crosslinked polyethylene can have several advantages over cables insulated with oil/paper for HVDC
applications.
15 The advantages of crosslinked polyethylene include lower manufacturing costs, lower operation costs, easier maintenance for utilities, higher temperature ratings (such as 90 degrees C vs. 60 degreesC to 70 degrees C) to utilities, and environmental friendliness due to no oil leakage.
Polymeric dielectric insulating materials, particularly polyethylene without 2o modification, however, cannot be used for HVDC applications. These materials have local space charge buildup, which can significantly enhance local fields under surge or lightning impulse, have charge neutralizations during reverse polarity, which can reduce local DC breakdown strength, and have stress inversions due to temperature-dependent conductivity, which can reverse local field enhancement.
25 A known approach to develop HVDC polymeric cable insulation products has been to have low and well-distributed space charge traps. Space charge can be trapped by physical traps formed between crystallinity and amorphous boundaries or chemical traps due to chemical structures of substances. The instant invention, however, is a cable insulation made from a blend which includes an ethylene copolymer, such as an 3o ethylene-alpha olefin copolymer with low crystallinity to reduce physical space charge trapping sites. The invention uses at least one polar polymer modifier in an effective amount to enhance local conductivity to leak space charge quickly when local stress is enhanced, and at least one ion scavenger to stabilize or neutralize the space charge to provide a composition which is an effective high-voltage DC cable insulation.
The instant invention is also a semiconductive shield made from a blend that includes an ethylene copolymer, a carbon black having low levels of ionic species, a polar polymer modifier, and an ion scavenger.
SUMMARY OF THE INVENTION
The invention is directed to (1) a direct current cable, which includes insulation, to which resists breakdown and deterioration when exposed to high-voltage direct current,
(2) an insulation composition which resists deterioration and breakdown when exposed to high-voltage direct current, and (3) a method for reducing the deterioration of such insulation. The invention is also directed to a semiconductive shield with similar resistance to breakdown and deterioration.
The cable insulation composition includes at least one crosslinked nonpolar, low crystallinity resin with a density of less than 0.900grams/cubic centimeter which tends not to trap charge or create charge trap sites for a cable insulation temperature rating of at least 90degrees C. In another aspect, the resin is not crosslinked or is crosslinked only in a low amount (hereinafter a non-crosslinked polymer) which is 2o effective for providing a cable insulation with a temperature rating of 75degrees C or above. In either aspect, the cable insulation also includes (1) at least one polar polymeric modifier which dissipates or leaks charge quickly under high fields, (2) at least one ion scavenger which stabilizes or neutralizes space charges, and (3) optionally at least one heat stabilizer which minimizes internal charge generation during in service thermal degradation of insulation.
The crosslinked nonpolar low crystalline resin, polar polymeric modifier, ion scavenger and heat stabilizer are in amounts effective for achieving temperature rating of 90degrees C or above, a charge density less of than 2 Coulomb/mm3 measured by a pulsed electro acoustic (PEA) method after 24 hours with either positive or negative 20 3o kV/mm applied. For the cable insulation which has a temperature rating of not more than 75degrees C the amount and extent of crosslinking of such resin, the amounts of polar polymeric modifier, ion scavenger and heat stabilizer all are effective for achieving temperature rating of 75degreesC or above, a charge density less of than 2 Coulomb/mm3 measured by a pulsed electro acoustic (PEA) method after 24 hours with either positive or negative 20 kV/mm applied.
In another aspect, the invention is a high-voltage direct current cable insulation composition which has a temperature rating of 90degreesC or above and which comprises a blend of or which is made from a blend of at least one crosslinked ethylene copolymer, such as ethylene/alpha olefin copolymer, having a density of less than 0.900grams/cubic centimeter, a melt index of from 0.5 to lOgrams/10 minutes, a crystallinity of less than about 10 percent; at least one polar polymeric modifier in an l0 amount effective to provide field conductivity and permitting leakage of space and charge only at high fields; at least one ion scavenger in an amount effective to reduce charge build-up relative to a blend which does not include an ion scavenger;
and, optionally, at least one heat stabilizer in an amount effective to prevent thermally induced degradation and resulting internal charge generation. The polar polymeric modifier, ion scavenger, and optional heat stabilizer are in amounts and ratios which when in combination with the crosslinked resin provide the insulation with a charge density less than 2 Coulomb/mm3 measured by a PEA method after 24 hours with either positive or negative 20 kV/mm applied.
In another aspect, for cable insulation which has a temperature rating of 75degreesC or above, the cable insulation composition comprises a nonpolar, non-crosslinked ethylene copolymer, such as an ethylene/alpha olefin copolymer, having a density of less than 0.900 gramslcubic centimeter a melt index of from 0.5 to lOgrams/10 minutes, a crystallinity of less than about 10 percent; at least one polar polymeric modifier in an amount effective to provide field conductivity and permitting leakage of space and chaxge only at high fields; at least one ion scavenger in an amount effective to reduce charge build-up relative to a blend which does not include an ion scavenger; and, optionally, at least one heat stabilizer in an amount effective to prevent thermally induced degradation and resulting internal charge generation. The polar polymeric modifier, ion scavenger, and optional heat stabilizer are in amounts and ratios which when in combination with the resin provide the insulation with a charge density less than 2 Coulomb/mm3 measured by a PEA method after 24 hours with either positive or negative 20 kV/mm applied.
3 In yet another aspect, the invention is a high-voltage direct current cable insulation which comprises a blend of or which is made from a blend of at least one crosslinked ethylene/butene or ethylene/hexene olefin polymer having a density of less than 0.900grams/cubic centimeter, a melt index of from 0.5 to lOgrams/10 minutes;
from 0.1 to 15 weight percent of at least one polar polymeric modifier; from 0.05 to 0.5 weight percent of at least one charge scavenger to reduce charge build-up, and optionally, from 0.1 to 5 weight percent of at least one heat stabilizer in an amount effective to prevent thermally induced degradation and resulting internal charge generation.
l0 The semiconductive shield composition of the present invention includes (a) at least one nonpolar, low crystallinity resin with a density of less than 0.900grams/cubic centimeter, (b) a carbon black having low levels of ionic species, (c) at least one polar polymeric modifier, and (d) at least one ion scavenger. Optionally, the composition can include at least one heat stabilizer. The resin can be crosslinked or not. The polar polymeric modifier dissipates or leaks charge quickly under high fields. The ion scavenger stabilizes or neutralizes space charges. The optional heat stabilizer minimizes internal charge generation during in service thermal degradation of insulation. The resulting cable should achieve either a temperature rating of (a) 90degrees C or above or (b) 75degrees C or above.
BRIEF DESCRIPTION OF DRAWING
Figure 1 describes PEA space charge measurements after 24 hours at +20 kV/mm.
Figure 2 describes PEA space charge measurements after 24 hours at -20 kV/mm.
DESCRIPTION OF THE INVENTION
The nonpolar ethylene copolymer, which can be used in the invention, includes ethylene/alpha olefin interpolymers, such as an ethylene/propylene copolymer.
The resin has low crystallinity and has a density of less than 0.90grams/cubic centimeter. In a very important aspect, the resin used in the invention is a C2-C6 alpha olefin 3o copolymer. Low crystallinity means a crystallinity of less than 20 percent as determined by a differential scanning calorimeter. The alpha olefin resins, which may be used in the invention, include an ethylene-hexene copolymer made with a single site
4 catalyst (SSC), an ethylene-butene copolymer made with a Ziegler Natta (Z/N) catalyst, and an ethylene-octene copolymer made with a SSC catalyst. The nonpolar ethylene copolymer may have some polar components, but such polar components should not be in such an amount to make the resin crystalline and loose its amorphous characteristics.
Hence, the nonpolar resin may contain an ethylene/styrene copolymer, an ethylene vinyl acetate copolymer, or an ethylene/ethyl acrylate copolymer in low amounts. In the aspect of the invention, which includes a crosslinked resin, the resin may be crosslinked using a peroxide, irradiation or a moisture cure.
Polar polymer modifiers are polymeric materials having at least one polar to component. These polar components may be a part of the polymer structure as side groups which group may be residues of malefic anhydride, vinyl acetate and vinyl acrylate, where such compounds have been incorporated into the polymer, such as by grafting or were a part of the monomer precursor of the polymer. Polar components also may include hydroxyl group, styrenic group and carboxyl group. The polar polymeric modifier may be polyethylene glycol (where the polar component is hydroxyl group), ethylene ethyl acrylate (where the polar component is a residue of vinyl acrylate), ethylene styrene copolymer (where the polar component is a styrenic group) or a polyester having an acid number (where the polar component is a carboxyl group). The polar polymer modifiers may include malefic-anhydride-grafted very low 2o density ethylene/alpha olefin copolymers having a density of less than about 0.900grams/cubic centimeter as described above having about 0.3 percent malefic anhydride, polycaprolactone resins (having a carboxyl group in the main chain with a diol group at the end) and mixtures thereof.
Ion scavengers are compounds that have chelating groups, such as hydroxyl and carboxyl. Ion scavengers may include 1,2-bis(3,5-di-tert-butyl-4 hydroxyhydrocinnamoyl) hydrazine, poly[[6-[1,1,3,3-tetramethylbutyl)amino]-s triazine-2,4-diyl] [2,2,6,6-tetramethyl-4-piperidyl)imino]hexamethylene [(2,2,6,6 tetramethyl-4-piperidyl)imino], N,N'-bis(0-hydroxybenzal) oxalydihydride, barbituric acid, tertiary phosphorous acid ester of a thiobisphenol, and N,N'-diphenyuloxamid, 3o and mixtures thereof.
Antioxidants also may be put into the insulation or semiconductive shield compositions. Antioxidants, which may be used, include: 1,3,5-tris(4-tent-butyl-3-
5 hydroxy-2,6-dimethylbenzyl)-1,3,5-tria.zine-2,4,6-(1H, 3H, 5H)-trione, commercially available as Cyanox 1790; and distearylthiodipropionate (DSTDP).
For semiconductive shield compositions, the carbon black should have a low level of ionic species, preferably less than about 200 ppm. More preferably, the amount of ionic species is less than about 100 ppm. The amount of ionic species of a carbon black can be determined by Induction Coupling Plasma Spectroscopy or the method described in J. Tanaka, "Interfacial Aging Phenomena In Power Cable Insulation systems", Institute of Materials Science, University of Connecticut, Progress Report No. 8 and 9, September 13, 1988.
l0 For a crosslinked insulation composition with a temperature rating of 90degrees C, its elongation and set at a temperature of 150degreesC per ICEA T-test method should not be greater than 175 percent and 10 percent, respectively. The alternative referee method is the solvent extraction test per ASTM D2765. The crosslinked insulation composition generally will have maximum extractables after 20 hours drying time of no more than 30 percent. Insulation with a temperature rating of 75degreesC generally requires having percent retained tensile strength and elongation at break of no less than 70 percent after heat aged at 113degreesC for 7 days in air-circulated over per UL-1581 standard.
Examples 1-7 Examples l, 2, 3, 4 and 6 illustrate the invention. Examples 5 and 7 are comparative examples.
For each example, the base ethylene polymer was characterized as having low crystallinity and a low melt index and as being a very low density polyethylene: (a) Exact 4033TM ethylene/hexene copolymer; (b) DGH-8480TM ethylene/butene copolymer; or (c) Engage 8003TM ethylene/octene copolymer. Unless otherwise indicated in Table 1, the exemplified composition contained Exact 4033TM
ethylene/hexene copolymer as the base polymer.
Exact 4033TM ethylene/hexene copolymer, having a density of 0.880 grams/cubic centimeter and a melt index of 0.8 grams/10 minutes, is a single-site 3o catalyzed polyethylene available from Exxon Chemical Co. DGH-8480TM
ethylene/butene copolymer, having a density of 0.884 grams/cubic centimeter and a melt index of 0.8 gramsll0 minutes, is available from The Dow Chemical Company.
6 Engage 8003TM ethylene/octene copolymer, having a density of 0.885 grams/cubic centimeter and a melt index of 1.0 grams/10 minutes, is a single-site catalyzed polyethylene available from DuPont Dow Elastomers LLC.
All of the exemplified compositions also contained 0.25 weight percent of Chimassorb 944 poly[[6-[1,1,3,3-tetramethyl-butyl)amino]-s-triazine-2,4-diyl]
[2,2,6,6-tetramethyl-4-piperidyl)imino]hexamethylene[(2,2,6,6-tetramethyl-4-piperidyl)imino]]
as an ion scavenger, 0.14 weight percent of Cyanox 1790 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H, 3H, SH)-trione as a primary antioxidant, and 0.23 weight percent of DSTDP as a secondary antioxidant.
l0 Chimassorb 994 is available from Ciba Specialty Chemicals Corporation.
Cyanox 1790 is available from Cytec Corporation. DSTDP is available from Great Lakes Corporation.
Also, each composition was cured with bis(1-methyl-1-phenylethyl) peroxide, which is available from Hercules Corporation.
Various other components were used in the exemplified composition. DEFA-1373TM very low density ethylene/butene copolymer, having a 0.3 weight percent malefic anhydride graft, is available from The Dow Chemical Company and characterized as a polar polymer modifier. DEFA-1373 has a density of 0.903 grams/cubic centimeter and a melt index of 2.0 grams/10 minutes. Tone Polymer P-767TM polylactone resin has a density of 1.145 grams/cubic centimeter, a melt index of 30.0 grams/10 minutes, and melting point of 60 degrees C. P-767 polylactone resin is available from The Dow Chemical Company and characterized as a polar polymer modifier. Zinc oxide, which was added as a heat stabilizer/phonon dissipator, is available as Kadox 911P from Zinc Corporation of America. Irganox 1024 1,2-bis(3,5-di-tert-butyl-4-hydroxyhydrocinnamoyl)hydrazine, which was added as an ion scavenger, is available from Ciba Specialty Chemicals Corporation.
The space charge measurements were performed by a pulsed electro acoustic method. The details of this method can be found in literature as described in Y. Li, M.
Yasuda, and T. Takad, "Pulsed Electro-acoustic Method for Measurement of Charge 3o Accumulation in Solid Dielectrics, " IEEE Transaction EI, Vol. l, pp. 188-195, 1994.
Each sample had l.6mm thickness with a diameter of 135mm, placed between semicon electrodes of O.lmm and a diameter of 30mm, placed between semicon
7
8 PCT/US2003/029070 electrodes of O.lmm and diameter of 30mm. The application of 32 kV DC (20 kV/mm) was applied for 24 hours, and space charge was measured by PEA without voltage applied as shown in Figure 1. The sample was grounded without applied voltage for 12 hours, and then voltage was applied with -32 kV DC (20 kV/mm) for 24 hours.
The space charge without voltage applied was measured again by the PEA as shown in Figure 2. All measurements were done at ambient temperature about 20degrees C.
Space charge measurements were plotted as charge density (Coulomb per cubic millimeter) as a function of time (nano-second). Each division shown in Figures 1 and 2 is equivalent to a value of 2 Coulomb/mm3.
1o For HVDC cable applications, HVDC cable insulation should keep the space charge as low as possible and as uniform as possible throughout the measurement of time. The value of space charge measurement for excellent HVDC cable insulation should be no more than 2 Coulomb/mm3 for both positive and negative DC stress.

~C oo ' W

~ o U o ~i o a, ~ c N O O O

l~ O '~ 01 W 01 (V O 01 O

SC oo ' W m N

U ~ a1, N O O O O N

~ ~ o O O

z W oo ~ cV N O 01 H

O

O O
Z

1- W 01 N (VO 01 a U a\

O

H N N O O N

h" l~ O ,-i01 H

O

,_,oo O ' N O O N

01 O '-'01 W oo .~ O o .

O

N

O

~ o O ~ i O

', bA .

~ ~ >, O ..~~-, s-, .
~ >, +~

O _ N ~ O N V~ Eo _ O

N ~ ~ ~ ~ p O ~ by . ~ ~ ~ ~ bA
~

U . w U ~ ~ ~ 'N ~ ~ ~

.

Effect of Additives Comparative Example 5 containing typical antioxidants and UV stabilizer did not meet the desired requirement on space charge value at the applied positive DC
stress of 20 kV/mm. However, Examples 1 and 2 with Irganox 1024 and two different polar polymer modifiers, respectively, met the desired requirements at both positive and negative DC stresses. Example 2 showed lower space charge distribution than Example 1. Example 3 with additional heat stabilizer, zinc oxide, showed further improvement in space charge when compared with Example 2. Example 4 with the combination of additive packages from Example 3 and 1 showed acceptable space to charge performance.
Effect of the Resins Examples 2 and 6 and Comparative Example 7 showed the effect of various VLDPE resins on space charge distribution. Comparative Example 7 made by octene comonomer did not meet the space charge distribution criteria with the levels of polymer modifier and ion scavenger shown.
io

Claims (10)

CLAIMS:
1. A high-voltage direct current cable insulation comprising:

a blend of or which is made from a blend of:

(a) at least one ethylene copolymer, having a density of less than 0.900 grams/cubic centimeter, a melt index of from 0.5 to 10 grams/10 minutes, a crystallinity of less than 10 percent and a catalyst residue of less than 1000 ppm, selected from the group consisting of (i) ethylene/alpha olefin copolymers, and (ii) nonpolar, low crystalline ethylene copolymers selected from the group consisting of ethylene/propylene copolymer and ethylene/styrene copolymer and mixtures thereof;

(b) at least one polar polymer modifier in an amount effective to provide an insulation made with the blend with an enhanced field conductivity and enhanced space charge leakage at high fields relative to an insulation made with a blend which does not include a polar polymer modifier, wherein the polar polymer modifier is present in an amount of at least 0.1 weight percent; and (c) at least one ion scavenger in an amount effective to reduce ionic mobility relative an insulation made with a blend which does not include an ion scavenger, wherein the ion scavenger is present in an amount of at least 0.05 weight percent, wherein the cable insulation has a charge density of less than 2 Coulomb/mm3 measured by a pulsed electro acoustic method after 24 hours with either positive or negative 20 kV/mm.
2. A high-voltage direct current cable insulation comprising:
a blend of or which is made from a blend of (a) at least one ethylene/alpha olefin copolymer having a density of less than 0.900 grams/cubic centimeter, a melt index of from 0.5 to 10 grams/10 minutes, a crystallinity of less than 10 percent and a catalyst residue of less than 1000 ppm;

(b) from 0.1 to 15 weight percent of at least one polar polymer modifier having at least one polar component; and (c) from 0.05 to 0.5 weight percent of at least one ion scavenger having at least one chelating component, wherein the cable insulation has a charge density of less than 2 Coulomb/mm3 measured by a pulsed electro acoustic method after 24 hours with either positive or negative 20 kV/mm applied.
3. The high-voltage direct current insulation of claim 1 or 2, wherein (a) the polar polymer modifier is selected from the group consisting of (i) a polymer having a density of less than 0.900 grams/cubic centimeter with at least one side group selected from the group consisting of hydroxyl, carboxyl, styrenic;
(ii) a polymer having a density of less than 0.900 grams/cubic centimeter and at least one side group which is a residue of maleic anhydride, vinyl acetate or vinyl acrylate;
(iii) a polylactone resin and; (iv) mixtures thereof, and (b) the ion scavenger has at least one chelating group.
4. The high-voltage direct current insulation of any one of claims 1 to 3, wherein the ethylene copolymer is crosslinked.
5. A high-voltage direct current cable comprising:
(a) an electrical conductor; and (b) cable insulation comprising:

a blend or which is made from a blend of:

(i) at least one nonpolar, low crystalline ethylene copolymer selected from the group consisting of ethylene/propylene copolymer and ethylene/styrene copolymer and mixtures thereof, the ethylene copolymer having a density of less than 0.900 grams/cubic centimeter, a melt index of from 0.5 to 10 grams/10 minutes, a crystallinity of less than 10 percent and a catalyst residue of less than 1000 ppm;

(ii) at least one polar polymer modifier having at least one polar component in an amount effective to provide an insulation made with the blend with an enhanced field conductivity and enhanced space charge leakage at high fields relative to an insulation made with a blend which does not include a polar polymer modifier, wherein the polar polymer modifier is present in an amount of at least 0.1 weight percent; and (iii) at least one ion scavenger having at least one chelating component in an amount effective to reduce ion mobility relative to an insulation made with a blend which does not include an ion scavenger, wherein the ion scavenger is present in an amount of at least 0.05 weight percent, wherein the cable insulation with has a charge density of less than 2 Coulomb/mm measured by a pulsed electro acoustic method after 24 hours with either positive or negative 20 kN/mm applied.
6. The high-voltage direct current cable as recited in claim 5, wherein the ethylene copolymer is crosslinked.
7. A method for providing a cable insulation with a charge density of less than 2 Coulomb/mm measured by a pulsed electro acoustic method after 24 hours with either positive or negative 20 kN/mm applied, the method comprising:

(a) mixing:

(i) at least one ethylene/alpha olefin copolymer having a density of less than 0.900 grams/cubic centimeter, a melt index of from 0.5 to 10 grams/10 minutes, a crystallinity of less than 10 percent and a catalyst residue of less than 1000 ppm;

(ii) from 0.1 to 15 weight percent of at least one polar polymer modifier having at least one polar component;

(iii) from 0.05 to 0.5 weight percent of at least one ion scavenger having at least one chelating component, wherein the cable insulation has a charge density of less than 2 Coulomb/mm3 measured by a pulsed electro acoustic method after 24 hours with either positive or negative 20 kN/mm applied.
8. A high-voltage direct current cable semiconductive shield comprising:
a blend of or which is made from a blend of:

(a) at least one ethylene copolymer, having a density of less than 0.900 grams/cubic centimeter, a melt index of from 0.5 to 10 grams/10 minutes, a crystallinity of less than 10 percent and a catalyst residue of less than 1000 ppm, selected from the group consisting of (i) ethylene/alpha olefin copolymers and (ii) nonpolar, low crystalline ethylene copolymers selected from the group consisting of ethylene/propylene copolymer and ethylene/styrene copolymer and mixtures thereof;

(b) a carbon black having a low level of ionic species;

(c) at least one polar polymer modifier in an amount effective to provide a semiconductive shield made with the blend with an enhanced field conductivity enhanced space charge leakage at high fields relative to a semiconductive shield made with a blend which does not include a polar polymer modifier, wherein the polar polymer modifier is present in an amount of at least 0.1 weight percent; and (d) at least one ion scavenger in an amount effective to reduce ionic mobility relative to a semiconductive shield made with a blend, which does not include an ion scavenger, wherein the ion scavenger is present in an amount of at least 0.05 weight percent.
9. The high-voltage direct current semiconductive shield of claim 8, wherein (a) the polar polymer modifier is selected from the group consisting of (i) a polymer having a density of less than 0.900 grams/cubic centimeter with at least one side group selected from the group consisting of hydroxyl, carboxyl, styrenic;
(ii) a polymer having a density of less than 0.900 grams/cubic centimeter and at least one side group which is a residue of maleic anhydride, vinyl acetate or vinyl acrylate;
(iii) a polylactone resin and; (iv) mixtures thereof, and (b) the ion scavenger has at least one chelating group.
10. The high-voltage direct current semiconductive shield of claim 8 or 9, wherein the ethylene copolymer is crosslinked.
CA2497032A 2002-10-07 2003-09-16 High-voltage direct current cable insulation and semiconductive shield Expired - Fee Related CA2497032C (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US10/263,328 US6670554B1 (en) 2002-10-07 2002-10-07 High-voltage direct current cable insulation
US10/263,328 2002-10-07
PCT/US2003/029070 WO2004034408A1 (en) 2002-10-07 2003-09-16 High-voltage direct current cable insulation and semiconductive shield

Publications (2)

Publication Number Publication Date
CA2497032A1 CA2497032A1 (en) 2004-04-22
CA2497032C true CA2497032C (en) 2012-12-04

Family

ID=29735651

Family Applications (1)

Application Number Title Priority Date Filing Date
CA2497032A Expired - Fee Related CA2497032C (en) 2002-10-07 2003-09-16 High-voltage direct current cable insulation and semiconductive shield

Country Status (8)

Country Link
US (2) US6670554B1 (en)
EP (1) EP1552535B1 (en)
JP (2) JP2006502552A (en)
AT (1) ATE346362T1 (en)
AU (1) AU2003270691A1 (en)
CA (1) CA2497032C (en)
DE (1) DE60309910T2 (en)
WO (1) WO2004034408A1 (en)

Families Citing this family (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6670554B1 (en) * 2002-10-07 2003-12-30 Union Carbide Chemicals & Plastics Technology Corporation High-voltage direct current cable insulation
US20060116456A1 (en) * 2004-11-30 2006-06-01 Lin Thomas S Composition with enhanced heat resistance property
JP5437250B2 (en) * 2007-09-25 2014-03-12 ダウ グローバル テクノロジーズ エルエルシー Styrenic polymer as a blending component to control adhesion between olefinic substrates
KR101355572B1 (en) 2009-02-19 2014-01-24 엘에스전선 주식회사 Extra high voltage cable
CN102687356B (en) 2009-09-14 2015-11-25 罗杰.福克纳 Underground modular high-voltage direct current electric power transmission system
JP5830848B2 (en) * 2010-10-29 2015-12-09 ダイキン工業株式会社 Surface treatment agent and composition, processed product
RU2500047C1 (en) * 2012-05-03 2013-11-27 ЗАО "Лидер-Компаунд" Electroconductive peroxide cross-linkable composition
CA2908972C (en) 2013-04-18 2022-08-02 Dow Global Technologies Llc Coated conductor with voltage-stabilized inner layer
CN103613828B (en) * 2013-11-26 2015-12-30 无锡市明珠电缆有限公司 A kind of high voltage direct current cable material and its preparation method and application
WO2016097254A1 (en) * 2014-12-19 2016-06-23 Borealis Ag Power cable polymer composition, power cable and uses with advantageous properties
WO2016097250A1 (en) * 2014-12-19 2016-06-23 Borealis Ag Polymer composition for w&c application with advantageous electrical properties
JP7088923B2 (en) * 2016-12-01 2022-06-21 ダウ グローバル テクノロジーズ エルエルシー Peroxide curable polyolefin composition
FR3079067B1 (en) * 2018-03-19 2020-03-20 Nexans ELECTRIC CABLE COMPRISING AN EASILY PEELABLE POLYMERIC LAYER
CN111989361B (en) 2018-04-26 2023-06-27 陶氏环球技术有限责任公司 Polyolefin additive formulations
CN109438807B (en) * 2018-10-29 2020-12-01 北京科技大学 Insulating material and preparation method and application thereof
CN112858801A (en) * 2021-01-08 2021-05-28 青岛科技大学 Method and system for reducing space charge injection under direct-current high electric field

Family Cites Families (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59152937A (en) * 1983-02-18 1984-08-31 Mitsui Petrochem Ind Ltd Ethylene-alpha-olefin copolymer composition
US5237014A (en) * 1989-05-08 1993-08-17 Union Carbide Chemicals & Plastics Technology Corporation Tree resistant compositions
JPH0765633A (en) 1993-08-20 1995-03-10 Fujikura Ltd Dc cable
JPH09231839A (en) 1996-02-20 1997-09-05 Showa Electric Wire & Cable Co Ltd Direct current cable
KR20010024534A (en) 1997-10-17 2001-03-26 그래햄 이. 테일러 Compositions of interpolymers of alpha-olefin monomers with one or more vinyl or vinylidene aromatic monomers
SE512580C2 (en) 1997-11-03 2000-04-03 Abb Ab Process for preparing a material, composition and use of the composition
SE511215C2 (en) 1997-12-22 1999-08-23 Asea Brown Boveri Dielectric gelling composition, use thereof, insulated electric DC cable comprising such composition and process for making it
SE511214C2 (en) 1997-12-22 1999-08-23 Asea Brown Boveri Dielectric gelling composition, method of manufacture thereof and an electric DC cable comprising an insulation system impregnated with such composition
SE514062C2 (en) 1997-12-22 2000-12-18 Abb Ab Isolated electric DC cable
SE514263C2 (en) 1997-12-22 2001-01-29 Abb Ab An electric DC cable with an insulation system comprising an extruded polyethylene composition and a method for manufacturing such a cable
SE511942C2 (en) 1998-02-06 1999-12-20 Abb Ab A method of manufacturing a cable with an insulation system comprising an extruded, cross-linked conductive polyethylene composition
SE9800567L (en) 1998-02-25 1999-08-26 Abb Ab An electric DC cable with an insulation system comprising a composition based on extruded, cross-linked polyethylene and a method for making such a cable
WO1999058615A1 (en) * 1998-05-11 1999-11-18 Union Carbide Chemicals & Plastics Technology Corporation High solids conductive coatings compositions suitable for electrostatic atomization application methods
DK1283527T3 (en) * 2000-03-31 2006-07-03 Sumitomo Electric Industries Electrical insulating resin composition and electrical wire or cable, both coated therewith
JP2001312922A (en) * 2000-04-28 2001-11-09 Sumitomo Electric Ind Ltd Plastic insulating composition and electrical wire, cable, cable connecting part using the same
US6670554B1 (en) * 2002-10-07 2003-12-30 Union Carbide Chemicals & Plastics Technology Corporation High-voltage direct current cable insulation

Also Published As

Publication number Publication date
ATE346362T1 (en) 2006-12-15
JP2012009436A (en) 2012-01-12
DE60309910T2 (en) 2007-04-12
DE60309910D1 (en) 2007-01-04
EP1552535B1 (en) 2006-11-22
US20040112618A1 (en) 2004-06-17
US6670554B1 (en) 2003-12-30
EP1552535A1 (en) 2005-07-13
JP5431419B2 (en) 2014-03-05
JP2006502552A (en) 2006-01-19
US6924435B2 (en) 2005-08-02
CA2497032A1 (en) 2004-04-22
AU2003270691A1 (en) 2004-05-04
WO2004034408A1 (en) 2004-04-22

Similar Documents

Publication Publication Date Title
JP5431419B2 (en) High voltage DC cable insulator and semiconductive shield
Hanley et al. A general review of polymeric insulation for use in HVDC cables
KR101732756B1 (en) Medium voltage cable insulation
KR101859852B1 (en) Polypropylene resin and Power cable comprising the same in insulation layer
KR101362560B1 (en) Cross-linked polyethylene compositions
US11257607B2 (en) Electric cable with improved temperature ageing resistance
KR20170139696A (en) Energy Cable Having a Voltage Stabilized Thermoplastic Electrically Insulating Layer
WO2011159611A2 (en) Insulation containing styrene copolymers
US10703889B2 (en) Insulated electric wire and insulating resin composition
JPWO2001075904A1 (en) Electric insulating resin composition and electric wire or cable coated with the same
US20140017494A1 (en) Insulations containing non-migrating antistatic agent
JP7159912B2 (en) insulated wire and cable
JPH10283851A (en) Direct current power cable and its connection part
WO2013140692A1 (en) Non-halogen flame retardant resin composition, and electric wire and cable using same
RU2399105C1 (en) Power cable
CN107709443B (en) Cable insulation composition comprising a sulfur-containing second antioxidant
KR100561272B1 (en) Crosslinked polyolefin composition having excellent electrical property and thermal stability
JP2017191657A (en) LAN cable
JP2001325834A (en) Dc power cable
US20240062930A1 (en) Electric cable comprising a thermoplastic insulating layer with improved electrical and mechanical performance
KR20180131339A (en) High voltage DC power cable joint system
KR20200079201A (en) Electric cable resistant to water trees
JP2023038166A (en) Polyolefin resin composition with high resistance to tracking and article molded therefrom
FR3124760A1 (en) cable comprising a compact fire-retardant sheath
Kumar et al. Underground Cable Construction: A Survey

Legal Events

Date Code Title Description
EEER Examination request
MKLA Lapsed

Effective date: 20200916