CN1322362A - Electric dc-cable with insulation system comprising extruded polyethylene composition and method for manufacturing such cable - Google Patents
Electric dc-cable with insulation system comprising extruded polyethylene composition and method for manufacturing such cableInfo
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- CN1322362A CN1322362A CN99811805A CN99811805A CN1322362A CN 1322362 A CN1322362 A CN 1322362A CN 99811805 A CN99811805 A CN 99811805A CN 99811805 A CN99811805 A CN 99811805A CN 1322362 A CN1322362 A CN 1322362A
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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
- H01B3/30—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
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B9/00—Power cables
- H01B9/02—Power cables with screens or conductive layers, e.g. for avoiding large potential gradients
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- Spectroscopy & Molecular Physics (AREA)
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- Extrusion Moulding Of Plastics Or The Like (AREA)
Abstract
An electric DC-cable with an insulation system comprising an extruded polyethylene composition and a method for manufacturing such a cable. The insulating system comprises an extruded cross-linked polyethylene based insulation disposed around the conductor. The extruded insulation system in addition to the polyethylene based compound includes an additive, which is a glycerol fatty acid ester of the general formula (I): R<1>O(C3H5(OR<2>)O)nR<3> where n>/=1, R<1>, R<2>, and R<3>, which are the same or different, designate hydrogen or the residue of a carboxylic acid with 8-24 carbon atoms, with the proviso that there are at least two free OH groups and at least one residue of a carboxylic acid with 8-24 carbon atoms in the molecule. In the method for producing the DC-cable the compounded polyethylene based composition is extruded and cross-linked at a temperature and for a period of time sufficient enough to cross-link the insulation.
Description
Technical field
The present invention relates to a kind of isolated dc cable, promptly a kind of like this direct current (DC) cable, it comprises charged (curtage) body, i.e. conductor, and be configured in insulation system around the conductor, wherein this insulation system comprises extrusion molding and crosslinked polyethylene composition.
The invention particularly relates to a kind of isolated dc cable that is used to transmit with electrical power distribution.Its extrusion molding insulation system comprises a plurality of layers, for example inner semiconductor layer, insulating barrier and out semiconductor layer.At least this extrusion molding insulating barrier comprises the electric insulation composition based on crosslinked polyethylene, and the latter comprises additive system such as crosslinking agent, scorch retarder and antioxidant.
Background of invention
Be used for carrying electric power system with electrical power distribution that many DC techniques that are based on are arranged in early days.Yet the system that these technology are used alternating current (being AC) rapidly replaces.The AC system has desirable feature, promptly carries out conversion between generating voltage, transmission voltage and distribution voltage easily.Half leaf before 20th century, the development of modern electric power system all are based on the AC transmission system.To generation nineteen fifty, the long distance power transmission scheme has had growing demand, clearly, adopts the system based on direct current to be beneficial in some cases.Predictable advantage comprises and has reduced the problem that interrelates with the AC stability of a system and occur, more effectively utilizes equipment, because the power factor of system is 1 forever, and can use given insulation thickness and gap under higher operation voltage.As the opposite of these extremely important advantages, have to weigh and AC is converted into DC uses, and DC changes back to terminal equipment expensive of AC again.But, for given transmission power, the terminal cost is fixed.Therefore, for relating to remote scheme, it is economical that the DC conveying system just becomes.For example, the DC-technology for example with regard to the typical case, when transmission distance surpasses certain-length, consequently surpasses under the terminal factory condition of cost in the saving on the transmission facility for the system of plan long distance power transmission, and it is worthwhile just to become.
A significant benefit of DC operation is in fact to have eliminated dielectric loss, therefore huge income is arranged on efficient, can save on equipment.The DC leakage current is very little, so that can ignore in rated current is calculated, and dielectric loss causes the obvious decline of rated current in the AC cable.This is crucial for higher system voltage.Similarly, in the DC cable, high capacitance is not a burden.Typical case's direct current transmission cable comprises conductor and insulation system, and the latter comprises many layers, for example inner semiconductor layer, insulating body layer and out semiconductor layer.Cable can be designed to also comprise that overcoat and rib grade, with the infiltration of resisting water and in manufacturing, installation and any mechanical wear or the power that may be subjected between the operating period.
So far, the direct current cables system of nearly all supply all is to be used for submarine laying or the land that interrelates is with it laid.The remote cable of selecting the tight paper insulation type of integral body-dipping of laying does not cause restriction because do not exist because of adding pressure request to length.This type one is to being to use for the 450kV operating voltage.Although all adopt at present the paper insulators of electric insulation oil-impregnated basically, however laminate, and among for example the laminated thing of the polypropylene paper purposes that is used to be up to 500kV voltage was being explored, pulse strength improved and the advantage of reduced in the hope of obtaining.
As the situation at the AC handling cable, when determining the insulation thickness of DC cable, transient voltage also is the factor that will consider.Find, when in system, adding, when cable is in full load, situation about bothering most can occur with the opposite polarity transient voltage of operating voltage.If this cable is connected with overhead system, just can this kind trouble situation take place owing to thunder and lightning transient process (shock wave).
Based on polyethylene, i.e. PE, and crosslinked polyethylene, i.e. XLPE, extrusion molding closely insulation in exchanging defeated, distribution cable insulation, used similar 40 years.Therefore, studying the possibility that XLPE and PE are used for the DC cable insulation for many years always.The cable that has this kind insulation has the advantage identical with the mass-impregnation cable, that is, to loop length without limits, and they also have the potentiality that are operated under the higher temperature when being used for direct current transportation.Under the situation of XLPE, can be operated in 90 ℃, rather than 50 ℃ of traditional integral dipping DC cable, thereby the possibility that improves the transmission of electricity load is provided.Yet, on the full-size(d) cable, really do not given play to whole potentiality of this kind material so far as yet.It is believed that one of the main reasons is, do to produce space charge in time spent Jie's () matter when being subjected to DC electric field.This kind space charge is distorted stress distribution and because polymer resistive height and last very long.Space charge in the insulator will gather under the DC electric field action, form a kind of polarization general layout like that thereby be similar to capacitor.Space charge gathers general layout (figure) 2 kinds of fundamental types, and difference is that polarity that space charge gathers and the pass of above-mentioned (DC electric field) polarity fasten.Space charge gathers and causes actual electric field at some some place, has local increasing for the electric field that dopes when the physical dimension of considering insulator and the dielectric property.Observed this kind increase may be equivalent to predict 5 of electric field in actual electric field, even 10 times.Therefore, the design electric field of cable insulation must comprise considers the electric field factor that exceeds greatly and the coefficient of safety of taking, thereby causes adopting in cable insulation thicker and/or more expensive material.The formation that space charge gathers is a slow process, and therefore, when the polarity that forms under same polarity when the cable long-time operation was reversed, it is more serious that this problem will become.The result who puts upside down is, is superimposed with a capacitance field on the electric field that forms again being gathered by space charge, and the maximum field stress point will be inner to insulation from interfacial migration.For the effort that improves this situation is taked to utilize additive to reduce insulation resistance always, the not serious again way that influences other performances of while.So far, the electric property and the impregnated paper insulation cable that are reached are compared favourably, and also on commercial size, not lay any polymer insulation direct current cables.Yet it is reported the 250kV cable that adopts XLPE and filling mineral filler successfully in laboratory test, to make maximum stress to equal 20kV/mm (JiCable ' 91, pp.562～569 for people such as Y.Maekawa, " research and development of DC XLPE cable ").This stress value still forms distinct contrast with the representative value 32kV/mm that the mass-impregnation paper cable is adopted.
The extrusion molding resin combination of typical case's ac cable insulation usefulness comprises polyvinyl resin as base resin, is equipped with various additive, as peroxide cross-linking agent, scorch retarder and antioxidant or antioxidant systems.Under the situation of extrusion molding insulation, also extrude a semiconductive shielding layer usually, the resin combination that it comprises also comprises the additive of substantially the same type except comprising base polymer and conduction or semiconductive filler.Various extrusion molding layers in the general insulated cable are usually based on polyvinyl resin.Polyvinyl resin generally and in this application also is meant, a kind of resin based on polyethylene or ethylene copolymer, and the therein ethylene monomer accounts for the overwhelming majority of material.For example, polyvinyl resin can or multiplely can constitute with the monomer of ethylene copolymer by ethene and a kind.LDPE, promptly low density polyethylene (LDPE) is the main insulation basic material that is used for ac cable at present.For the physical property of improving extrusion molding insulation and in degradation resistant and the anti-capacity of decomposition making, transport, lay and using under dominance condition influences during this kind cable, comprise for example following additive usually based on poly composition:
-stabilising additive, for example antioxidant, electronics scavenger are to offset the decomposition that causes because of oxidation, irradiation etc.;
-lubricating additive, stearic acid for example is to improve processability;
-improve the additive of tolerance electric stress ability, for example improve water-fast tree (water treeresistance) ability, as polyethylene glycol, siloxanes etc.; And
-such as the crosslinking agent of peroxide, it is decomposed into free radical and causes the cross-linking reaction of polyvinyl resin after meeting heat, also cooperate sometimes with
-can improve the unsaturated compound of crosslink density;
-scorch retarder is to avoid crosslinked too early.
Various and may the making up of they of additive types is actually infinite.When selecting a kind of additive or additive combination or one group of additive, target should be that a kind or multiple performance will improve, and other performances will keep simultaneously, perhaps also improve if possible.Yet, in fact, predict that the caused all possible side effect of a certain change of additive system hardly may.In other cases, the improvement of being pursued is so important, so that has to accept some small negative effect that it brings, although always reduce this kind negative effect as far as possible.
The typical polyvinyl resin composition that is used as the extrusion molding cross linked insulation in the ac cable comprises:
100 weight portion low density polyethylene (LDPE) (922kg/m
3), its melt flow rate (MFR
2) equal 0.4～2.5g/10 minute;
0.1～0.5 phr (umbers of per 100 parts of resins) antioxidant, SANTONOXR (Flexsys Co.) for example, its chemical name is 4,4 '-sulfo--two (the 6-tert-butyl group-metacresols) or other antioxidant or antioxidant combination;
1.0～2.5phr crosslinking agent DICUP R
(Hercules Chem), its chemical name are dicumyl peroxide.
Yet well-known, all cross-linked polyethylene compositions that are used as the extrusion molding insulation in the ac cable system show all that under the direct current stress strong space charge gathers tendency, thereby they are not suitable in the insulation system of direct current cables.Know that also the long-time degassing even the cable after crosslinked is exposed in high temperature, the high vacuum environment for a long time, is gathered tendency with the space charge that makes it under the direct current stress and alleviated to a certain extent.Generally believe that vacuum treatment is disposed peroxide decomposition from insulation, for example " acetophenone " and " cumic alcohol ", thus make space charge gather minimizing.The degassing is about the same time-consuming as paper insulated dipping, so with high costs equally.Therefore, if can omit to the degassing needs, that will be favourable.
Goal of the invention
The direct current cables that the purpose of this invention is to provide a kind of insulation, it has in the direct current transportation of being adapted at and distribution network and the facility electric insulation system as the power transmission and distribution cable.This cable will comprise a kind of tight extrusion molding insulating layer of conductor, its apply and process all do not need to cable carry out any such as the dipping or the degassing, i.e. tediously long, the time-consuming batch process of vacuum treatment and so on.Whereby, can realize the cable production time shortening and thereby the reduction of production cost, thereby a kind of possibility of continuous basically or semicontinuous at least production cable insulation system is provided.Moreover, comprise original reliability, the low maintenance requires and long service live based on traditional direct current cables of the insulation of mass-impregnation paper, will be kept even be improved.In other words, cable of the present invention will have stable and consistent dielectric property, and high and consistent electrical strength.This cable insulation will show that low space charge gathers tendency, high direct current destroys (puncture) intensity, high impulse intensity and high insulation resistance.The band of impregnated paper or cellulose base changes the extruded polymers insulation into, as extra advantage is, a kind of raising electrical strength will be provided, thereby allows to strengthen the possibility of operating voltage, then make cable lighter, more firm.
Another purpose provides a kind of cable, it comprise extrusion molding, crosslinked, be mainly poly insulation, space charge during bearing direct current stress in the insulation gathers low or does not have, and gathers the problem that interrelates thereby eliminate or significantly reduce at least with space charge.The present invention also will be provided at the ability of the design load aspect reduction coefficient of safety of determining that the cable insulation size is adopted.
Another purpose provides a kind of insulation manufacture method of this kind of the present invention isolated dc cable.This applies and processes the method for conductor insulation on the one hand by the present invention, need not implement tediously long batch process to whole length or very long one section cable core with not relating to basically.This method also shows the potential possibility that is used for the very long direct current cables of production length according to continuous or semicontinuous mode.
Summary of the invention
Now be surprised to find, relevant can randomly cooperate with other additives by being incorporated into a kind of special glycerine fatty acid ester additive in the XLPE composition, realize at cable at the chromatic effect that goes out aspect space charge gathers under the DC electric field influence.
Therefore, the invention provides a kind of direct current power cable, it comprises conductor and is configured in around the conductor, comprises at least 3 layers extrusion molding, crosslinked, tight insulation system, it is characterized in that, this extrusion molding insulation system comprises and is mainly poly compound, wherein the additive of the Jia Ruing additive that comprises crosslinking agent, scorch retarder, antioxidant and contain general formula (I) fatty acid glyceride
R
1O(C
3H
5(OR
2)O)
nR
3????(I)
Wherein
N 〉=1, preferably, because market supply, n=1～20, more preferably n=3～8,
R
1, R
2And R
3, can be identical or different, represent the carboxylic acid residues of hydrogen or 8～24 carbon atoms,
Condition is in this molecule, the carboxylic acid residues of at least 2 free hydroxyl group groups and at least 1 8～24 carbon atom to be arranged.At R
2And R
3All represent hydrogen and R
1=R, promptly under the situation of carboxylic acid residues, this general formula will be taked its simple form (II)
RO(CH
2CH(OH)CH
2O)
nH????(II)
Polyvinyl insulation after mixing is being extruded and is being heated to a certain high temperature in typical case, and keeps one period that is enough to make insulation crosslinked.Temperature and time should be controlled to such an extent that make cross-linking process reach best.
The cable insulation system can utilize continuous basically method to be applied on the conductor, need be such as vacuum treatment tediously long batch process.Containing dipping low spatial electric charge that paper insulated traditional direct current cables possessed gathers and is all kept with high direct current breakdown strength or improve.The insulation property of direct current cables of the present invention show general long-time stability, cause the working life of cable to be maintained or prolong.
The present invention also provides a kind of production method of direct current cables as mentioned above.In its most general form, comprise conductor and extrusion molding, crosslinked, comprise the following steps: based on the production method of the isolated dc cable of the conductor insulation of polyethylene
-lay or a kind of any conductor that requires shape and structure that otherwise is shaped;
-mixing a kind of based on polyethylene and comprise the resin combination of crosslinking agent, scorch retarder, antioxidant and space charge depressant and so on additive;
-extrude the resin combination of this mixing back based on polyethylene, be distributed in the conductor insulation around the conductor in the direct current cables (preferably, this three-layer insulated system that comprises insulating barrier and be aided with 2 semiconductive shielding layers adopts real triple extrusion molding to apply up) thereby form;
-make the insulation of extruding take place crosslinked;
-wherein according to the present invention, in polyvinyl resin, add the space charge depressant that contains general formula (I) fatty acid glyceride when mixing;
R
1O(C
3H
5(OR
2)O)
nR
3????(I)
Wherein
N 〉=1, R
1, R
2And R
3, can be identical or different, represent the carboxylic acid residues of hydrogen or 8～24 carbon atoms, condition is in this molecule, the carboxylic acid residues of at least 2 free hydroxyl group groups and at least 1 8～24 carbon atom to be arranged.
-and wherein mixing after the resin combination based on polyethylene be extruded, and depress at high temperature and adding and to carry out crosslinked and keep one section to be enough to make insulation that the crosslinked time takes place.
Explanation and claims below having studied carefully become clear afterwards naturally about other notable features of the present invention and advantage.
Detailed Description Of The Invention
For using extruded polyethylene or crosslinked polyethylene (XLPE), there is Several Factors to consider as the insulation of direct current cables.Most important thing is that the space charge under the direct current stress gathers.The present invention makes the space charge that occurs usually in the direct current cables under the mode of operation gather remarkable reduction, is to realize by the additive that adds a small amount of general formula (I) structure in polyethylene or crosslinkable polyethylene compound.The compound of general formula (I) is a kind of list-or poly-glycerine ether, and wherein the carboxylic acid of at least 1 hydroxyl and 8～24 carbon atoms has generated ester.Preferably, the compound of general formula (I) structure is a kind of monoether, and in other words, its per molecule comprises 8～24 carbon atom carboxylic acid's residues.Have, this becomes ester carboxylic acid preferably to generate ester with the primary hydroxyl group of glycerol compounds again.The compound of general formula (I) can comprise 1～20, and is preferred 1～15,3～8 glycerine unit most preferably, that is and, the n in the general formula (I) equals 1～20, and is preferred 1～15, and most preferably 3～8.
R in general formula (I)
1, R
2And R
3When not representing hydrogen, they represent the carboxylic acid residues of 8～24 carbon atoms.These carboxylic acids can be saturated or undersaturated, branching or non-branching.As the indefiniteness of this kind carboxylic acid example *+-be laurate, nutmeg acid, palmitic acid, stearic acid, oleic acid, linoleic acid, leukotrienes and behenic acid.When carboxylic acid residues when being undersaturated, this unsaturated bond can be used to the compound of general formula (I) structure is bonded on the ethene polymers of composition, thereby and prevents that effectively the compound of structural formula (I) from moving away from composition.
In general formula (I), R
1, R
2And R
3Can represent the same carboxylic acids residue, for example stearoyl, perhaps different carboxylic acids residue, for example stearoyl and oleoyl.
For prevent the migration and ooze out, the compound of structural formula (I) should be compatible with the composition that comprises it, especially with composition in the resin compatible based on ethene.
The compound of structural formula (I) is compound known or can adopts the known method preparation.For example, the compound of a kind of general formula (I) corresponding to n=3 by ICI (Britain) as trade name Atmer
184 (or 185) available commercial, a kind of in addition, its n on average equals 8, and per molecule contains a fatty acid residue, can be by ICI by trade name SCS 2064
Obtain.The known available compound that other available general formulas (II) are described is TST 221
(n=6, R=linoleic acid residue (unsaturated C18 acid)), TST 215
(n=6, R=stearic acid (saturated C18 acid)) and TST 216
(n=6, R=behenic acid (unsaturated C22 acid)) all supplied by Danisco (Denmark).
The addition of compound in the present composition of general formula (I) is for suppressing effective quantity that space charge under the DC stress effect gathers effect.Generally speaking, this is meant that the addition of the compound of general formula (I) is about 0.05～2wt% of composition weight, preferred 0.1～1wt%.
Except the compound of general formula (I), the compound composition that the present invention is used for direct current cables also can comprise conventional additive, and antioxidant for example is to offset the decomposition that causes because of oxidation, irradiation etc.; Lubricating additive, for example stearic acid; Crosslinking additives is for example met thermal decomposition and is caused the peroxide of cross-linking reaction; And other additives, for example scorch retarder and compatilizer.The total amount of additive comprises the compound of present composition formula of (I), should be no more than about 10wt% of composition weight.
Except the compound and other tradition above-mentioned and optional additives of general formula (I), the present composition comprises the top pointed ethene polymers that is in the great majority.Polyvinyl selection and composition depend on that said composition prepares as the insulating barrier of cable or as the interior or outer semiconducting layer of cable actually.
The composition of the insulating barrier of cable of the present invention for example can comprise about 0.05～about 2wt% general formula (I) compound and other tradition and optional additive; 0～about 4wt% peroxide cross-linking agent; The remainder of composition then is made of ethene polymers basically.This kind ethene polymers is LDPE preferably, that is, and and Alathon or ethene and a kind or the alpha-olefin of multiple 3～8 carbon atoms such as the copolymer of 1-butylene, 4-methyl-1-pentene, 1-hexene and 1-octene.This a kind or multiple alpha-olefin components contents can be equivalent to about 1%～about 40wt% of vinyl monomer weight.Also can use ethene with a small amount of, that is, and the copolymer of the highest 5wt%1 kind or various polarity component such as vinyl acetate, methyl acrylate, ethyl acrylate, butyl acrylate or dimethylamino-propyl methyl acid amides (DMAPMA).
Similarly, the composition of the semi-conductive layer of cable can comprise, and is equivalent to compound and other tradition and the optional additive of about 0.05%～about 2wt% general formula (I) of weight ethylene polymer; About 30～80wt% ethene polymers; Quantity is enough to make composition to become semiconductive carbon black, preferred about 15～45wt% carbon black; 0～about 30wt% acrylonitrile-butadiene copolymer; And 0～about 4wt% peroxide cross-linking agent.In this connection, this ethene polymers is ethylene copolymer or the ethylene copolymer such as EVA (ethene-vinyl acetate), EMA (ethylene-methyl acrylate), EEA (ethylene-propylene acetoacetic ester) or EBA (ethylene-propylene acid butyl ester) that is described to be suitable as the composition of insulating barrier.
Direct current cables of the present invention owing to have the extrusion molding cross linked insulation system that comprises cross-linked polyethylene composition, XLPE and structural formula (I) additive, will show quite significantly advantage, for example:
-space charge gathers obvious reduction, and thus, the raising of direct current breakdown strength.
According to the cable among the following embodiment, the present invention also provides the premium properties and the stability of extruding cable insulation system, even if extrude, crosslinked or other hot conditionss had once adopted high temperature in handling.
Direct current cables of the present invention provides the ability that allows to adopt basic continuation method production, without any need for time-consuming step at intermittence such as the dipping or the degassing, reduce the production time thereby provide greatly, thereby and the possibility that reduces production costs, and do not have the anxiety of infringement cable technology performance.
Understand the present invention for further helping, some indefiniteness case illustrated will be provided below.In these embodiments, all compositions are unit representation with the umber of per 100 parts by weight resin all, unless point out separately.
The accompanying drawing summary
Below with reference to the accompanying drawings and embodiment, the present invention is described in more detail.Fig. 1 represents to use by the high voltage DC power transmission of one embodiment of this invention the sectional drawing of cable.Fig. 2 represents the structure of breadboard.Fig. 3～14 expression space charge surveying record that the breadboard of used XLPE composition and the present composition obtains from prior art insulation ac cable.
Preferred embodiment, embodiment describe
The direct current cables of one embodiment of this invention shown in Figure 1 therefrom mind-set comprises outward:
Many one metal wires of-standard conductor 10;
-Di 1 extrusion molding semiconductive shielding layer 11 is configured in the inboard of the outside around the conductor 10 and conductor insulation 12;
-extrusion molding conductor insulation 12 comprises extrusion molding, cross-linked composition;
-Di 2 extrusion molding semiconductive shielding layers 13 are configured in the outside of conductor insulation 12;
-metal screen layer 14; And
-external coating or epitheca 15 are configured in metal screen layer 14 outsides.
Think appropriate, in this direct current cables, can also various modes replenish into various functional layers or other features.For example, it can replenish with at the wire form reinforcing agent in extrusion molding screen 13 outsides, be incorporated into sealed compound or water-soluble bloated powder or moistureproof system in the metal/polymer interface, this can reach by for example corrosion resistant metal polyethylene layer compound, and vertical waterproof, by water-soluble bloated material, for example band below epitheca 15 and powder reach.It is wire that conductor not necessarily requires, and can be the shape and the structure of any requirement, for example is a kind of wire multi-filament conductor, solid conductor or fan-shaped section conductor.
The employed breadboard 20 of the described mensuration distribution of space charge of Fig. 2 comprise 2 semiconductive electrodes of forming by carbon black filling ethylene copolymer 21 with and form insulator as shown in table 1 22.
Fig. 3,5,7,9,11 and 13 show be in " voltage connections " pattern, adopt distribution of space charge value that arbitrary unit represents along with and grounding electrode between distance and the situation of variation.Similarly, Fig. 4,6,8,10,12 and 14 show be in " voltage shutoffs " pattern, adopt distribution of space charge value that arbitrary unit represents along with and grounding electrode between distance and situation about changing (attention, the ratio that " voltage connection " and " voltage shutoff " pattern (figure in) are adopted is different).
For helping to understand the present invention, will provide some indefiniteness case illustrated below.In the following embodiments, made breadboard with various different components and measure its space charge by the record space charge-distribution curve and gather situation.These curves adopt pulse electroacoustic (PEA) technical notes to arrive.The PEA technology is known in this area,, is described in pp.497～501 (1987) at " IEEE Trans.Elec.Insul. " volume EI-22 (the 4th phase) by people such as Takada.Space charge curve shown in the following embodiment, or " voltage connection ", promptly, the space charge curve under the electric stress effect that after direct voltage has applied 3 hours, records, or " voltage shutoff " state, that is the space charge curve that (before the ground connection, direct voltage has applied 3 hours) immediate record is arrived after the whole ground connection of electrode.
Composition shown in the table 1 all carries out mixing making by traditional approach by each component in plastic extruding machine.Breadboard is by the two-step method manufacturing.The 1st step, under 130 ℃, carried out press molding 30 minutes by the band material of extruding, the circular slab of making diameter 210mm, thickness 2mm is as insulator.The 2nd step, at the center of each face of circular insulating board (be total to) 2 semiconductive electrodes are installed, unless point out separately subsequently, assembly heated 15 minutes at 180 ℃ in electronic press without exception.Why a high thermoperiod will be set, and is in order to reach crosslinked fully.Subsequently, breadboard is cooled to ambient temperature under pressure.During the press molding, adopt Mylar
Film is as backing.The semiconductive electrode is by the commercially available prod LE 0500 of Borealis (Sweden) supply
Make.This blend composition comprises ethylene-butyl acrylate copolymer and acetylene black.These electrodes are of a size of, thick 1mm, diameter 50mm.Fig. 2 demonstrates the structure and the size of breadboard.
The space charge curve of breadboard is write down under 50 ℃ by a kind of PEA analytical equipment.An electrode grounding, another then maintains+40kV voltage, that is and, plate internal electric field strength maintenance is at 20kV/mm.In space charge curve chart 3～14, the electric charge of unit volume is represented as the function of breadboard thickness, and in other words, grounding electrode place functional value is zero, x point out towards high voltage (+40kV) electrode direction is left the distance of grounding electrode.In " voltage connection " pattern, after voltage applies 3 hours, record space electric charge curve.In " voltage shutoff " pattern, in case the space charge curve is after high-voltage electrode ground connection under (that is, through keep 3 hours under+40kV after) immediate record.This space charge curve is by adopting any unit of charge to provide in the unit volume insulator.The multiplication factor that is adopted during " voltage shutoff " is higher than during " voltage connection ".Yet concerning all samples, any ratio that adopts of 2 kinds of patterns all is comparable.
Example 1,2 and 3 is Comparative Examples.The composition of the insulating material in these examples is corresponding to invention disclosed among the Swedish patent application 9704825-0 (1997-12-22).
Example 1
The polyethylene breadboard of the thick composition A of 2mm (referring to table 1), have 2 semiconductive electrodes and 180 ℃ carried out 15 minutes crosslinked, in the PEA analytical equipment, 50 ℃ of following reception tests.Breadboard is inserted between 2 straight electrodes, and accepts the DC electric field effect of 40kV voltage.In other words, an electrode grounding, another electrode maintain+current potential of 40kV.Accepting to record space charge curve shown in Figure 3 under what is called " voltage connection " pattern of direct current stress after 3 hours.The unit volume electric charge is represented as the function of breadboard thickness with arbitrary unit, and in other words, the grounding electrode place is zero, and x points out to leave the distance of grounding electrode towards the direction of+40kV electrode.
Fig. 4 is presented at the terminal point that 3 hours high voltages electrify, the space charge curve under what is called " voltage shutoff " pattern that and then high-voltage electrode ground connection is later.At this moment, the unit volume space charge is represented as the function of breadboard thickness with arbitrary unit (when being different from " voltage connection " pattern), that is, the grounding electrode place is zero, and x points out to leave towards original high-voltage electrode direction the distance of grounding electrode.
Example 2
In order to test the effect of from insulation system, driving all volatile matters out of,, under high vacuum, 80 ℃ of conditions, handled 72 hours with example 1 identical type and at 15 minutes breadboard of 180 ℃ of crosslinked mistakes.After this handles, record space electric charge curve.Fig. 5 represents " voltage connection " pattern, and Fig. 6 represents " voltage shutoff " pattern.
Example 3
In order to test crosslinked condition effect, crosslinked 30 minutes at 250 ℃ with the breadboard of example 1 identical type.Breadboard is tested in the PEA analytical equipment.Fig. 7 provides " voltage connection " pattern, and Fig. 8 provides " voltage shutoff " pattern.
Example 4
The polyethylene breadboard of the thick composition B of 2mm (referring to table 1), have 2 semiconductive electrodes and 180 ℃ carried out 15 minutes crosslinked, in the PEA analytical equipment, under 50 ℃, test.Breadboard is inserted between 2 straight electrodes, and accepts the DC electric field effect of 40kV voltage.In other words, an electrode grounding, another electrode maintain+current potential of 40kV.Under what is called " voltage connection " pattern of direct current stress after 3 hours, record space charge curve shown in Figure 9.The unit volume electric charge is represented as the function of breadboard thickness with arbitrary unit, and in other words, the grounding electrode place is zero, and x points out along leaving the distance of grounding electrode towards the direction of+40kV electrode.
Figure 10 demonstrates the terminal point that electrifies at 3 hours high voltages, the space charge curve under what is called " voltage shutoff " pattern that and then high-voltage electrode ground connection is later.At this moment, the unit volume space charge is represented as the function of breadboard thickness with arbitrary unit (when being different from " voltage connection " pattern), that is, the grounding electrode place is zero, and x points out to leave towards original high-voltage electrode direction the distance of grounding electrode.
Example 5
In order to test the effect of from insulation system, driving all volatile matters out of,, under high vacuum, 80 ℃ of conditions, handled 72 hours with example 4 identical type and at 15 minutes breadboard of 180 ℃ of crosslinked mistakes.After this handles, record space electric charge curve.Figure 11 provides " voltage connection " pattern, and Figure 12 provides " voltage shutoff " pattern.
Example 6
In order to test crosslinked condition effect, crosslinked 30 minutes at 250 ℃ with the breadboard of example 4 identical type.Breadboard is tested in the PEA analytical equipment.Figure 13 provides " voltage connection " pattern, and Figure 14 provides " voltage shutoff " pattern.
Can clearly be seen that relatively that from the space charge curve of the space charge curve of example 1,2 and 3 and example 4,5 and 6 compound of general formula (I) is a kind of extremely effectively space charge depressant.Be clear that from table 2 under conditions of similarity, when adding the compound of general formula (I) in insulation composition, the space charge that is gathered has reduced more than 50%.
For the space charge of showing general formula (I) compound gathers the fixing of depression effect, the example 7,8 and 9 below having carried out.
Example 7
In order to check the ultimate density dependence of general formula (I) compound, the polyethylene breadboard of the thick composition C of 2mm (referring to table 1), have 2 semiconductive electrodes and 180 ℃ carried out 15 minutes crosslinked, in the PEA analytical equipment, under 50 ℃, test." voltage connection " pattern is identical with Fig. 9 and 10 respectively with the space charge curve of " voltage shutoff " pattern.
Example 8
For the space charge of checking antioxidant systems mutual-through type (I) compound reduces the influence of ability, made 3 kinds respectively, i.e. the breadboard of composition D, E and F (referring to table 1), and by example 1 described the test.All these 3 kinds of breadboards all demonstrate, though " voltage connection " pattern or " voltage shutoff " pattern, identical with Fig. 9 and 10 respectively space charge curve.
Example 9
For the space charge of investigating other additive mutual-through type (I) compounds reduces the influence of ability, made respectively 3 kinds different, i.e. the breadboard of composition G, H and I (referring to table 1), and by example 1 described the test.All these 3 kinds of breadboards all demonstrate, though " voltage connection " pattern or " voltage shutoff " pattern, identical with Fig. 9 and 10 respectively space charge curve.
Can be clear that from the result of example 7,8 and 9 general formula of adding (I) compound can play the effect of effective space charge depressant on the crosslinked polyethylene compositing range of non-constant width.
Table 1
The composition of XLPE insulation blend composition
| The blend composition code name | A | B | C |
| LDPE*，MFR 2＝0.8 | 100 | 100 | 100 |
| LDPE*，MFR 2＝2 | - | ?- | - |
| Irganox?1035** | 0.2 | ?0.2 | 0.2 |
| Irganox?PS802*** | 0.4 | ?0.4 | 0.4 |
| Antioxidant 3 | - | - | - |
| Antioxidant 4 | - | - | - |
| General formula (I) compound: polyglyceryl list-fatty acid ester (SCS 2064) * * * * | - | 0.6 | 0.9 |
| The N-methyl pyrrolidone | - | - | - |
| Compatilizer 1 | - | - | - |
| Compatilizer 2 | - | - | - |
| Dicumyl peroxide | 1.8 | 1.8 | 1.8 |
| Scorch retarder * * * * * | 0.4 | 0.4 | 0.4 |
| Add up to | 102.8 | 103.4 | 103.7 |
* LDPE, low density polyethylene (LDPE), that is, and the polyethylene (density=0.922g/cm of high-pressure free radical polymerization preparation
3).
* Irganox 1035
, the 3-of sulfo-diethylene glycol (DEG) (3, the 5-di-tert-butyl-hydroxy phenyl) propionic acid diester, Ciba-Geigy company.
* * Irganox PS 802
, two octadecyl-thiodipropionates, Ciba-Geigy company.
* * * ICI, Britain
* * * * 2,4-diphenyl-4-methyl-amylene-1, Nofmer MSD
, Nippon Oil andFats (Nof Corp.).
Table 1 (continuing)
The composition of XLPE insulation blend composition
| The blend composition code name | D | E | F |
| LDPE*，MFR 2＝0.8 | 100 | 100 | 100 |
| LDPE*，MFR 2＝2 | - | - | - |
| Irganox?1035** | 0.15 | 0.2 | 0.2 |
| Irganox?PS?802*** | - | - | - |
| Antioxidant 3 | 0.08 | - | - |
| Antioxidant 4 | - | ?0.2 | 0.2 |
| General formula (I) compound: polyglyceryl list-fatty acid ester (SCS 2064) * * * * | 0.6 | 0.6 | 0.35 |
| The N-methyl pyrrolidone | - | - | - |
| Compatilizer 1 | - | - | - |
| Compatilizer 2 | - | - | - |
| Dicumyl peroxide | 1.8 | 1.8 | 1.8 |
| Scorch retarder * * * * * | 0.4 | 0.4 | 0.4 |
| Add up to | 103.3 | 103.2 | 102.95 |
* LDPE, low density polyethylene (LDPE), that is, and the polyethylene (density=0.922g/cm of high-pressure free radical polymerization preparation
3).
* Irganox 1035
, the 3-of sulfo-diethylene glycol (DEG) (3, the 5-di-tert-butyl-hydroxy phenyl) propionic acid diester, Ciba-Geigy company.
* * Irganox PS 802
, two octadecyl-thiodipropionates, Ciba-Geigy company.
* * * ICI, Britain
* * * * 2,4-diphenyl-4-methyl-amylene-1, Nofmer MSD
, Nippon Oil andFats (Nof Corp.).
Table 1 (continuing)
The composition of XLPE insulation blend composition
| The blend composition code name | G | H | I |
| LDPE*，MFR 2＝0.8 | 100 | - | 100 |
| LDPE*，MFR 2＝2 | - | 100 | - |
| Irganox?1035** | 0.2 | 0.2 | 0.2 |
| Irganox?PS?802*** | 0.4 | 0.4 | 0.4 |
| Antioxidant 3 | - | - | - |
| Antioxidant 4 | - | - | - |
| General formula (I) compound: polyglyceryl list-fatty acid ester (SCS 2064) * * * * | 0.35 | 0.35 | 0.7 |
| The N-methyl pyrrolidone | 0.07 | 0.05 | 0.07 |
| Compatilizer 1 | - | 0.35 | - |
| Compatilizer 2 | 0.25 | - | - |
| Dicumyl peroxide | 1.8 | 1.8 | 1.8 |
| Scorch retarder * * * * * | 0.4 | 0.4 | 0.4 |
| Add up to | 103.47 | 103.55 | 103.57 |
* LDPE, low density polyethylene (LDPE), that is, and the polyethylene (density=0.922g/cm of high-pressure free radical polymerization preparation
3).
* Irganox 1035
, the 3-of sulfo-diethylene glycol (DEG) (3, the 5-di-tert-butyl-hydroxy phenyl) propionic acid diester, Ciba-Geigy company.
* * Irganox PS 802
, two octadecyl-thiodipropionates, Ciba-Geigy company.
* * * ICI, Britain
* * * * 2,4-diphenyl-4-methyl-amylene-1, Nofmer MSD
, Nippon Oil andFats (Nof Corp.).
Table 2
The relative size of the space charge that gathers in " voltage shutoff " pattern (after direct current electrified 3 hours under the 20kV/mm)
| Example | 1 | 2 | 3 | 4 | 5 | 6 |
| Composition corresponding to table 1 | A | A | A | B | B | B |
| Crosslinking temperature, ℃ | 180 | 180 | 250 | 180 | 180 | 250 |
| Handle (80 ℃/72h/ vacuum) afterwards | - | + | - | - | + | - |
| The relative size of the space charge that gathers in " voltage shutoff " pattern | 100 | 70 | 160 | 50 | 35 | 60 |
| Figure number | 4 | 6 | 8 | 10 | 12 | 14 |
Claims (18)
1. the direct current cables of an insulation, it comprise conductor and be configured in around the conductor, comprise at least 3 layers of extrusion molding, crosslinked, based on the polymer-matrix insulation system of the composition of polyethylene, XLPE, it is characterized in that this extrusion molding insulation system also comprises the additive of a kind of general formula (I) fatty acid glyceride except comprising the compound of polyethylene for the basis
R
1O(C
3H
5(OR
2)O)
nR
3??????(I)
Wherein
n≥1，
R
1, R
2And R
3, can be identical or different, represent the carboxylic acid residues of hydrogen or 8～24 carbon atoms,
Condition is that the carboxylic acid residues of at least 2 free hydroxyl group groups and at least 1 8～24 carbon atom is arranged in this molecule.
2. the direct current cables of claim 1 is characterized in that, in compound (I), and R
2And R
3All represent hydrogen atom and R
1=R, i.e. the carboxylic acid residues of 8～24 carbon atoms, also, this compound has general formula
RO(CH
2CH(OH)CH
2O)
nH????(II)
3. the direct current cables of claim 1 is characterized in that, n is 1～20, and is preferred 1～15, most preferably 3～8.
4. the direct current cables of any one in the claim 1～3 is characterized in that, the compound of general formula (I) is a monoesters.
5. the direct current cables of any one is characterized in that in the above claim, and this ester is to generate between the primary hydroxyl group of carboxylic acid and glycerol compounds.
6. the direct current cables of any one is characterized in that in the above claim, and the compound of general formula (I) is present in insulation and these two kinds of layers of semiconductive.
7. the direct current cables of any one in the claim 1～5 is characterized in that, the compound of general formula (I) exists only in the insulating barrier.
8. the direct current cables of any one in the claim 1～5 is characterized in that, the compound of general formula (I) exists only in the semi-conductive layer.
9. the direct current cables of any one is characterized in that in the above claim, and the amount of compound in polymer composition of general formula (I) is benchmark with actual composition weight, is 0.05wt% at least.
10. the direct current cables of claim 9 is characterized in that, the amount of compound in polymer composition of general formula (I) is benchmark with actual composition weight, between 0.05～2wt%, and preferred 0.1～1wt%.
11. the direct current cables of any one is characterized in that in the above claim, polymer composition comprises a kind or multiple conventional additive, for example antioxidant, crosslinking agent, lubricating additive, scorch retarder and compatilizer.
12. the direct current cables of claim 11 is characterized in that, conventional additive comprises general formula (I) compound, and the total amount in actual composition is no more than about 10wt% of actual composition weight.
13. the direct current cables of any one in the above claim, it is characterized in that this polyethylene (PE) is selected from the copolymer of alpha-olefin of Alathon, ethene and a kind or multiple 3～8 carbon atoms and the copolymer of ethene and vinyl acetate, methyl acrylate, ethyl acrylate, butyl acrylate and dimethylamino-propyl methyl acid amides (DMAPMA).
14. method of producing the isolated dc cable, this method comprises the following steps: mixing a kind of polyethylene (PE) composition, described mixing PE composition is extruded as the part of polymer-matrix insulation system and is configured in around the conductor, make the crosslinked XLPE of the becoming composition of PE composition subsequently, it is characterized in that, in the PE composition, add the compound of a kind of general formula (I)
R
1O(C
3H
5(OR
2)O)
nR
3????(I)
Wherein
n≥1，
R
1, R
2And R
3, can be identical or different, represent the carboxylic acid residues of hydrogen or 8～24 carbon atoms,
Condition is in this molecule, the carboxylic acid residues of at least 2 free hydroxyl group groups and at least 1 8～24 carbon atom to be arranged.
15. the method for claim 14 is characterized in that, the addition of compound (I) is a benchmark with actual composition weight, is 0.05% at least.
16. the method for claim 15 is characterized in that, the addition of compound (I) is a benchmark with actual composition weight, between 0.05～2wt%, and preferred 0.1～1wt%.
17. the method for any one is characterized in that in the above claim, also adds a kind or multiple other additives, for example antioxidant, lubricating additive, crosslinking agent, scorch retarder and compatilizer in composition.
18. the method for any one is characterized in that in the claim 15～17, the total amount of additive comprises general formula (I) compound that joins in every kind of composition, is no more than the 10wt% of actual composition.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE9802681A SE512745C2 (en) | 1998-08-06 | 1998-08-06 | Electric DC cable with insulation system comprising an extruded polyethylene composition and a method for producing such cable |
| SE9802681-8 | 1998-08-06 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1322362A true CN1322362A (en) | 2001-11-14 |
Family
ID=20412208
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN99811805A Pending CN1322362A (en) | 1998-08-06 | 1999-08-04 | Electric dc-cable with insulation system comprising extruded polyethylene composition and method for manufacturing such cable |
Country Status (11)
| Country | Link |
|---|---|
| EP (1) | EP1103052A1 (en) |
| JP (1) | JP2002522875A (en) |
| KR (1) | KR20010072260A (en) |
| CN (1) | CN1322362A (en) |
| AR (1) | AR019993A1 (en) |
| AU (1) | AU760355B2 (en) |
| CA (1) | CA2339541A1 (en) |
| MX (1) | MXPA01001363A (en) |
| NO (1) | NO20010592L (en) |
| SE (1) | SE512745C2 (en) |
| WO (1) | WO2000008655A1 (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100511494C (en) * | 2003-07-25 | 2009-07-08 | 普雷斯曼电缆及系统能源有限公司 | Continuous process for manufacturing electrical cables |
| CN102231295A (en) * | 2011-04-20 | 2011-11-02 | 大连沈特电缆有限公司 | Copper clad aluminum core polyethylene insulation direct current high pressure cable |
| CN108028525A (en) * | 2015-09-11 | 2018-05-11 | Abb瑞士股份有限公司 | The high direct voltage insulator for the conductor insulation for making to be loaded with DC voltage and affiliated manufacture method |
| CN109180969A (en) * | 2018-07-06 | 2019-01-11 | 三峡大学 | Salt crosslinked polyethylene molecular structure and the method for analyzing salt crosslinked polyethylene molecular structure building under external electric field under external electric field |
| CN109963902A (en) * | 2016-11-16 | 2019-07-02 | 陶氏环球技术有限责任公司 | Dissipation factor and additive receive the composition of sexual balance |
| CN115651105A (en) * | 2022-10-25 | 2023-01-31 | 哈尔滨理工大学 | Grafting modified crosslinked polyethylene water tree-resistant insulating material and preparation method and application thereof |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8257782B2 (en) | 2000-08-02 | 2012-09-04 | Prysmian Cavi E Sistemi Energia S.R.L. | Electrical cable for high voltage direct current transmission, and insulating composition |
| US6903263B2 (en) | 2000-12-27 | 2005-06-07 | Pirelli, S.P.A. | Electrical cable, particularly for high voltage direct current transmission or distribution, and insulating composition |
| US20020188867A1 (en) * | 2001-06-08 | 2002-12-12 | Bushey Robert D. | System and method for appliance adaptation and evolution |
| US8217105B2 (en) * | 2006-10-16 | 2012-07-10 | Basf Se | Stabilized medium and high voltage insulation composition |
| EP2297750B1 (en) * | 2008-06-05 | 2012-02-01 | Union Carbide Chemicals & Plastics Technology LLC | Method for producing water tree-resistant, trxlpe-type cable sheath |
| WO2015090644A1 (en) * | 2013-12-19 | 2015-06-25 | Abb Technology Ltd | A method for providing an insulated high voltage power cable |
| WO2016131478A1 (en) * | 2015-02-18 | 2016-08-25 | Abb Technology Ltd | Electric power cable and process for the production of electric power cable |
| US10703496B2 (en) | 2017-04-21 | 2020-07-07 | General Electric Company | Propulsion system for an aircraft |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IT1136539B (en) * | 1980-06-30 | 1986-08-27 | Pirelli | PERFECTED AERIAL LINE CONDUCTOR |
| GB2120449B (en) * | 1982-05-11 | 1986-06-18 | Standard Telephones Cables Ltd | Power cables |
-
1998
- 1998-08-06 SE SE9802681A patent/SE512745C2/en unknown
-
1999
- 1999-08-03 AR ARP990103854A patent/AR019993A1/en not_active Application Discontinuation
- 1999-08-04 WO PCT/SE1999/001335 patent/WO2000008655A1/en not_active Application Discontinuation
- 1999-08-04 EP EP99941942A patent/EP1103052A1/en not_active Withdrawn
- 1999-08-04 CN CN99811805A patent/CN1322362A/en active Pending
- 1999-08-04 AU AU55415/99A patent/AU760355B2/en not_active Ceased
- 1999-08-04 KR KR1020017001528A patent/KR20010072260A/en not_active Application Discontinuation
- 1999-08-04 JP JP2000564209A patent/JP2002522875A/en active Pending
- 1999-08-04 CA CA002339541A patent/CA2339541A1/en not_active Abandoned
- 1999-08-04 MX MXPA01001363A patent/MXPA01001363A/en unknown
-
2001
- 2001-02-05 NO NO20010592A patent/NO20010592L/en not_active Application Discontinuation
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100511494C (en) * | 2003-07-25 | 2009-07-08 | 普雷斯曼电缆及系统能源有限公司 | Continuous process for manufacturing electrical cables |
| CN102231295A (en) * | 2011-04-20 | 2011-11-02 | 大连沈特电缆有限公司 | Copper clad aluminum core polyethylene insulation direct current high pressure cable |
| CN108028525A (en) * | 2015-09-11 | 2018-05-11 | Abb瑞士股份有限公司 | The high direct voltage insulator for the conductor insulation for making to be loaded with DC voltage and affiliated manufacture method |
| CN108028525B (en) * | 2015-09-11 | 2020-03-06 | Abb瑞士股份有限公司 | DC high-voltage insulator and associated production method |
| CN109963902A (en) * | 2016-11-16 | 2019-07-02 | 陶氏环球技术有限责任公司 | Dissipation factor and additive receive the composition of sexual balance |
| CN109963902B (en) * | 2016-11-16 | 2022-04-15 | 陶氏环球技术有限责任公司 | Composition with balanced dissipation factor and additive receptivity |
| CN109180969A (en) * | 2018-07-06 | 2019-01-11 | 三峡大学 | Salt crosslinked polyethylene molecular structure and the method for analyzing salt crosslinked polyethylene molecular structure building under external electric field under external electric field |
| CN115651105A (en) * | 2022-10-25 | 2023-01-31 | 哈尔滨理工大学 | Grafting modified crosslinked polyethylene water tree-resistant insulating material and preparation method and application thereof |
| CN115651105B (en) * | 2022-10-25 | 2023-08-18 | 哈尔滨理工大学 | Grafted modified crosslinked polyethylene water tree resistant insulating material and preparation method and application thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CA2339541A1 (en) | 2000-02-17 |
| KR20010072260A (en) | 2001-07-31 |
| AU5541599A (en) | 2000-02-28 |
| SE512745C2 (en) | 2000-05-08 |
| WO2000008655A1 (en) | 2000-02-17 |
| NO20010592L (en) | 2001-02-22 |
| JP2002522875A (en) | 2002-07-23 |
| AR019993A1 (en) | 2002-03-27 |
| AU760355B2 (en) | 2003-05-15 |
| NO20010592D0 (en) | 2001-02-05 |
| EP1103052A1 (en) | 2001-05-30 |
| MXPA01001363A (en) | 2002-04-24 |
| SE9802681D0 (en) | 1998-08-06 |
| SE9802681L (en) | 2000-02-07 |
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