CN1007296B - Electric power cable - Google Patents
Electric power cableInfo
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- CN1007296B CN1007296B CN 85107046 CN85107046A CN1007296B CN 1007296 B CN1007296 B CN 1007296B CN 85107046 CN85107046 CN 85107046 CN 85107046 A CN85107046 A CN 85107046A CN 1007296 B CN1007296 B CN 1007296B
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Abstract
The present invention relates to a cable which is a high-performance cable of oil immersion and insulation. The cable is formed in such a manner that a conductor is coated and wound by an insulation body of a polypropylene film. The density of the polypropylene film is in the range of 0.905 to 0.915 g/cm<3>, and the birefringence is in the range of 0.020 to 0.035. The ratio of two kinds of axial strength (vertical tensile strength/horizontal tensile strength) is in the range of 5 to 15. The insulation layer is immersed with insulation oil, and dodecylbenzene (DDB) oil is preferably used as the insulation oil.
Description
The invention relates to the improvement of oil immersion insulated cable.
Insulating paper usually is used to make the oil-impregnated insulating interlayer (dielectric insulator) of oiledcable up to now.In recent years, banded polypropylene film has been used to make this class insulating barrier.This film also has a series of advantage except that beating by miles the insulating paper aspect dielectric breakdown voltage.Little as dielectric loss angle tangent, the dielectric constant approximately equal of dielectric constant and insulating oil.
Yet traditional polypropylene film insulated cable has a shortcoming, promptly is created in to go up very on a large scale with insulating oil and expands.Therefore, use polypropylene film that all restrictions must be arranged.For example, when the cable that is entwined when a usefulness polypropylene film was dipped into insulating oil, polypropylene film expanded, and caused the pressure on the cable core to increase.The result makes cable lose its flexibility, has weakened the flowability of adjacent films layer insulation oil simultaneously.As a kind of measure of avoiding the problems referred to above, film can be wrapped on the conductor than loose ground.Yet, when film twined than pine, sliding position or wrinkling just might appear.
Another shortcoming of traditional polypropylene film insulated cable is that at the mutual overlap of insulating tape, the flowability of insulating oil reduces between the adjacent films, may reach the degree that causes dielectric breakdown because of the polypropylene film surface roughness inadequately.
When polypropylene film impregnated in alkyl benzene oil, this class oil mainly was used as the insulating oil of extra-high voltage (EHV) level oil compression cable, and film expands with the rising of cable temperature, caused film thickness to increase.May reach that pressure enlarges markedly on the mutual overlap contact-making surface of film, cause the degree that causes film breaks with the expansion or the contraction of temperature because of cable.In addition, also can force outer membrane to fall among the formed gap of internal layer membrane adjacent layer, cause cable bad, its result reduces the electrical characteristic of cable.
Main purpose of the present invention provides a kind of oil immersion insulated cable with low dielectric loss and gratifying dielectric strength, and the insulator of this cable is made by twine at least the improved polypropylene film of one deck on conductor.Thereby eliminated the above-mentioned shortcoming that comprises excessive expansion.Another object of the present invention provides the oil immersion insulated cable of the type of discussing above; The insulator of this cable is made by twine at least the assembly of one deck polypropylene film and one deck brown paper on conductor.Thereby, not only eliminated expansion issues and also eliminated the mobile inadequate problem of insulating oil in the insulator.
The present invention realizes above-mentioned purpose by making a cable, and the characteristics of this cable are to have the insulator made from the oil immersion polypropylene film.The grade of insulator is: density is in 0.905～0.915 gram/cubic centimetre scope; Birefringence is in 0.020～0.035 scope; Two axial strength ratios (endwise tensile strength/transverse tensile strength) are in 5～15 scopes.
Other purpose of the present invention and characteristics are passed through most preferred embodiment described in detail below, and with reference to accompanying drawing, will be perfectly clear.
Figure 1A is a schematic diagram that twines the insulating barrier operation.
Figure 1B and 1C are the cutaway views of typical insulator structure of the present invention.
Fig. 2 demonstrates the cross section of an oil immersed type insulated power cable.
Fig. 3 is the perspective view of the oil immersion insulating barrier in Fig. 2 oil immersed type insulated cable.
Fig. 4 is the cross section of the contemplated typical insulator structure of the present invention, and it has represented a part of oil immersion insulating tape enlargedly, and wherein insulation layer structure changes.The oil clearance at the place, crosspoint shown in Fig. 3 forms the oil clearance that doubles normal depth.
Fig. 5 is the cross-sectional view that illustrates another embodiment of the present invention-ε classification.
The polypropylene material that term used herein " polypropylene " refers to have following grade: isotacticity is not less than 90%, is not less than 95% for better, is not less than 97% for better; Melt index (MI) is in/10 minutes scopes of 0.5 gram, and is best in/10 minutes scopes of/10 minutes-20 grams of 1 gram; The isotacticity that is lower than above-mentioned lower limit does not meet the requirements. Because it can increase the dilation with insulating oil, if melt index (MI) is lower than above-mentioned lower limit, with the dilation of insulating oil
Can increase equally. On the other hand, if melt index (MI) is higher than above-mentioned higher limit, the amount of polymer that is dissolved in the insulating oil increases, and the result rises the viscosity of insulating oil. In the polypropylene product of above-mentioned grade, those polypropylene materials that are fit to cable production of the present invention should satisfy the requirement of melt crystallization temperature (Tmc) in 105 °～120 ℃ scopes, and are best in 108 °～118 ℃ scopes. The polypropylene product that the melt crystallization temperature surpasses above-mentioned higher limit presents inferior film shaped characteristic, is difficult to produce uniform film. As a result, make the defective of medium even more serious.
The polypropylene film that is used for cable of the present invention requires density in 0.905～0.915 g/cc of scope, and is best in 0.907～0.912 g/cc of scope. If density is less than above-mentioned lower limit, will increase with the dilation of insulating oil. Otherwise, if density greater than above-mentioned higher limit, polypropylene film will become fragile, the mechanical strength of cable insulation will be not enough. If birefringence is less than above-mentioned limit value, polypropylene film will exceed allowed band with the expansion of insulating oil. If birefringence exceeds above-mentioned limit value, polypropylene film just is easy to break, and this might cause dielectric breakdown. Therefore, such polypropylene film can not reach purpose of the present invention. Be used for the polypropylene film of cable of the present invention in two axial strength ratios, namely film in tensile strength longitudinally divided by it the resulting merchant of horizontal tensile strength, require in the 5-15 scope, best in the 7-12 scope. If this ratio is less than above-mentioned lower limit, polypropylene film will exceed allowed band with the expansion of insulating oil. Otherwise if this ratio surpasses higher limit, the property difference that polypropylene film presents in different directions will exceed allowed band. The result forms in the process of insulator twining to cable with film, the machinability of polypropylene film significantly descend (for example, elongation, wrinkling or break).
Now, the typical method of producing the film that is used for cable of the present invention will be narrated by example.At first melting acrylic resin, is sheet by an extrusion pattern extruding then, is wrapped in and makes its cooling and curing on the chilling roll.Resulting sheet-like polypropylene is by one group of rolling roll shaft and rolling, its rolling than (the thick merchant of rolling anter) divided by the thick gained of rolling rear panel in the 5-12 scope, best in the 7-10 scope.
Rolling pressure is comparatively desirable in 10-3000 kg/cm scope, at 100-1000
Best in the kg/cm scope.The temperature of rolling roll shaft is comparatively desirable in 60 ° of-160 ℃ of scopes, and is best in 80～150 ℃ of scopes.During sheet-like polypropylene enters rolling roll shaft, by with a kind of suitable liquid (as water, the aqueous solution of surfactant, alkylene glycols, polyethylene glycol, glycerol or electric insulation oil) method on the sheet-like polypropylene surface of getting wet, polypropylene film can be easily evenly rolling with the rolling ratio of height.
Handle resulting polypropylene film (film thickness is in the 10-300 micrometer range usually) by the rolling and be heated to 100 °-150 ℃ once more, and under this temperature, stand the 1-20 heat treatment in second, the lax full-sized 0.5%-10% of the length on it is vertical.
Characteristics of the present invention are to have above-mentioned feature.By polypropylene film pyrocondensation proportional limit in the vertical in the 0.1%-5% scope, best in the 0.5%-3% scope, oil immersion insulated cable of the present invention can be in even more ideal obtaining in form., pyrocondensation causes the shortcoming of wrinkle if than surpassing above-mentioned higher limit, can causing the tension that insulating interlayer is easy to stretch tight.If the pyrocondensation ratio is less than above-mentioned lower limit, the extension on film is prone to vertically in insulating oil makes the insulating interlayer that is wrapped on the cable fluff.The typical method that limits vertical pyrocondensation ratio is, the polypropylene film of producing with said method is heated to 80 ° of-140 ℃ of temperature ranges, best in 90 ° of-130 ℃ of scopes, under this temperature, make film be in tensioned state or full-sized 0.1%-5% maintenance 0.5-50 hour that allow to relax in the vertical, 1-20 hour the best.By this aging heat treatment, vertically the pyrocondensation specific energy is limited in the 0.1%-5% scope, and is best in the 0.5%-3% scope.
Based on underlying cause, the thickness of polypropylene film should be limited in the 70-300 micrometer range.If film thickness is less than 70 microns, polypropylene film just very easily breaks, thereby can't guarantee with the polypropylene insulation band on the conductor to produce the desired mechanical strength of high-quality insulating interlayer, and concerning Manufactured oiledcable, can't keep cable to have and bear crooked required intensity, the result causes the insulating interlayer distortion, as wrinkling, dent, fracture etc.This all seriously jeopardizes the electrical characteristics of cable.
Usually, desired insulation thickness is to obtain by the film-insulated belt number that adjustment is wrapped on the conductor.If the thickness of insulating tape is little, the number of plies of insulating tape then increases in proportion, the result,
The volume of wrapping machine must increase, and comprises that simultaneously dress band, tape swapping, the workload of cutting band increase thereupon.If the thickness of polypropylene film is above 300 microns, insulating tape causes when insulating tape being wrapped on the conductor when making insulating interlayer with regard to having high toughness, (insulating tape) produces adapting to the resistance power of conductor column shape shape, and concerning the oiledcable of producing, can cause structural aberration, separate as insulating interlayer, the gap distribution between the insulating tape adjacent layer edge is irregular, and the electrical characteristic that usually all might seriously jeopardize cable.
Usually, in cable, forming insulating interlayer, come the stretch wrap film insulating tape according to the gap between the edge that allows the insulating tape adjacent layer on the conductor.Like this, the core intersection that forms in these gaps increases with the thickness of insulating tape.In oiledcable, the electric strength of oil reservoir is lower than the dielectric strength of insulating tape part.Therefore, the remarkable increase of core intersection is not desirable.
From above-mentioned various conditions, the process of producing oiledcable comprises, makes the various polypropylene films of thickness in the 70-300 micrometer range; These polypropylene films are cut into the polypropylene insulation band of proper width; (the side of contiguous conductor just in the inboard of insulator; Promptly be subjected to the strongest side of electric stress) twine the less polypropylene insulation band of thickness, though the relatively poor electrical characteristics of these insulating tape mechanical properties are quite good; (just outwards electric stress is less and be subjected to the side that crooked influence increases on it) twines the bigger polypropylene insulation band of thickness in the outside of insulating barrier, though the relatively poor mechanical performance of these insulating tape electrical characteristics is quite good.
Terminology used here " brown paper " or " insulating paper " refer to the common insulating paper that is used for the high oiledcable of arbitrarily downgrading traditionally.Based on the same reason about polypropylene film thickness that provides above, the brown paper thickness limits of using in the cable of the present invention is in the 70-300 micrometer range.
About being used in the insulating oil in the cable of the present invention, the present inventor finds to contain the alkyl benzene of aromatics, and the detergent alkylate (DDB) that particularly is used in usually in the cable is suitable for the present invention most.Usually, following condition is used as the criterion of choosing insulating oil:
(A) can buy at a low price;
(B) have the electrical characteristic of good stable:
(C) be adapted to very much the composition material of cable insulation.Specifically, in feelings of the present invention
Should fully be adapted to polypropylene film under the condition.
According to condition (A), (B), prove that detergent alkylate is a kind of desirable insulating oil.Yet with regard to condition (C), detergent alkylate is owing to cause polypropylene film expansion and not ideal enough.
Usually, the compatibility degree between film and the insulating oil is by they corresponding separately solubility parameters value (SP) decisions.Solubility parameters value with film and insulating oil is near each other, and the film in particular combinations and the similarity of insulating oil increase and insulating oil also improves the ability that film expands.The solubility parameters value of polypropylene and detergent alkylate all is approximately equal to 8.Like this, because their combination has highly compatible, and inevitable with high dilation, their combination up to now is considered to not as other combination ideals, as the combination of polypropylene and polybutene lubricating oil or the combination of polypropylene and silicone oil.
After the big in this respect quantity research, the present inventor finds, because the polypropylene film that insulating oil brought expansion is caused by the amorphous phase contrast of this insulating oil infiltration film.This amorphous phase contrast constitutes an electrical characteristics weak spot of polypropylene film, therefore from the viewpoint of electricity, strengthens the amorphous phase contrast and lubricating oil in the combination is become be easy to the expansioning polypropylene film and be worth.In addition, detergent alkylate has a phenyl ring, makes it to be good to absorb gas and stop corona discharge, and on this meaning, the detergent alkylate proof is more desirable aspect electrical property.According to present inventor's research, when the pulse breakdown value of a polypropylene film interlayer and detergent alkylate combination was got office 1, then the breakdown value with the silicone oil combination was about 0.8.This also is applicable to the alternating current breakdown intensity of polypropylene film.Under the condition of not sacrificing detergent alkylate and polypropylene film compatibility, be without prejudice for guaranteeing dodecane remarkable electrical characteristic basic and the polypropylene film combination, point out following solution:
As mentioned above, though is useful with detergent alkylate dipping polypropylene film from the viewpoint of electrical characteristic, before cable starts shipment, but placing the highest actual work temperature of being envisioned (in common 85～95 ℃ of scopes) to keep 24-28 hour on cable, it is saturated that polypropylene film is expand into.The improvement of this physical state guarantees that cable has good electrical characteristic at the very start from its service.
By research to polypropylene film, found out that polypropylene film can limit by the optimal values of selected thin film parameter in above-mentioned scope with the swell increment of detergent alkylate, these parameters comprise density, birefringence, the two axial strength ratios of film.Specifically, the film thickness expansion ratio in the combination of actual test shows polypropylene film of the present invention and detergent alkylate is 1/2nd of the film thickness expansion ratio that makes up of polypropylene and the detergent alkylate of even die casting.
For remedying this deficiency, on brown paper or polypropylene film surface or press with boss in surface both simultaneously, the size of boss is enough to cushion because the thickness that polypropylene film expands and increased to prevent pressure abnormal ascending in the insulating tape interlayer, is kept the flowability of lubricating oil.
When the single or double embossing alligatoring of polypropylene film that is used for cable of the present invention and brown paper, therefore and the maximum gauge of rugosity Rmax(surface pitting is stuck with paste on the surface that produces) require in 1～50 micrometer range, best in the 2-4 micrometer range.If surface roughness is less than above-mentioned lower limit, the polypropylene film swell increment deficiency of boss buffering, insulating oil is mobile insufficient in the interlayer, and the result can cause dielectric breakdown.Otherwise, if surface roughness surpasses above-mentioned higher limit, embossed might be damaged polypropylene film on the one hand, and boss occupies excessive volume on the other hand, so that finish the back in the film expansion and also have boss to exist, this just may cause insulating tape oil clearance to occur at mutual overlap.On effect, this has reduced the electric strength of interlayer.
The alligatoring on polypropylene film surface for example can be realized by embossed.Specifically, make polypropylene film of the present invention remain on 90 °～140 ℃ embossing roll by one group of temperature with the single or double alligatoring of polypropylene film.Surface roughness Rmax is in 1～50 micrometer range, best in 2～40 micrometer ranges.
For production is used for the film of cable of the present invention, rolling processing and embossed cooperate and prove ideal.Other method also is available, and for example, the rolling processing of above-mentioned cooperation can be by the rolling stretching processing replacement that roll was handled or prepared by the use low coverage in cooperation with stretching.Equally, above-mentioned cooperation embossed can replace reaching desired surface roughness by blasting treatment or corrosion treatment.
For alligatoring brown paper surface, the embossed of utilizing the embossing roll is ideal.In addition, a kind of processing of spraying the globule also is available.
Increase with the polypropylene film quantity of the present invention that is stacked on the insulating interlayer, reduce the film expansion except having by insulating oil, improve the flowability of insulating oil in the insulating interlayer and the mechanical property of insulating interlayer, improved film in the machinability in the winding process on conductor, reduce outside advantage such as too tight or too loose appears in layer, dielectric loss tangent of an angle (tan δ) and dielectric constant (ε) are improved.Therefore, resulting cable be applicable to voltage the 275-1000 kilovolt from the high service that is pressed onto the superhigh pressure level.And be specially adapted to superelevation and arbitrarily downgrade.
Alternately twine brown paper and polypropylene film and be the main points of making cable of the present invention, its reason is based on following 2 points: at first, thisly give the improvement with mechanical strength of the cable produced around layer; This mechanical strength is not readily accessible as the cable institute of insulating barrier without polypropylene film.Secondly, insert between the apparent surface of polypropylene film the brown paper that contains the polarity group with and distribution in whole insulator can play the effect that improves various electric strengths, particularly anti-pulse strength, especially anti-positive pulse intensity.
The coefficient of thermal expansion of brown paper is very little, in fact, and about little two orders of magnitude of coefficient of thermal expansion than polypropylene film.Compare with polypropylene film, brown paper also is less at the compressed coefficient of thickness direction.When many brown paper overlap and during the influence of temperature change that is subjected to bringing because of load change, it presents extremely strong adaptability.When brown paper was cut into band shape, the edge of band was very level and smooth, can not resemble to form sharp cut edge the polypropylene film.Because brown paper can be buffered in the deformation that occurs in production, transportation and the actual installation cable, therefore brown paper is used in combination in some way with polypropylene film, make brown paper have at least a surface and polypropylene film adjacent, can bring many advantages.Comprising be highly advantageous to internal pressure between the adjacent insulating tape of control of, the buffering usefulness of brown paper; Allow to select within a large range the condition of cable production; Make cable be easy to use, make like this in the cable of producing, allow insulating tape to slide over each other and the unlikely mutual dislocation that causes reposefully.In addition, brown paper cushions very equably also that any because polypropylene insulation band expands and the increase of the film thickness that thermal expansion causes, makes to be easy to the formation that remains on optimal values and stop gap between adjacent insulating tape at the internal pressure between adjacent insulating tape.
In two cable socket connection places, all be that insulating interlayer is at first untied in manual operations usually, then the connection place of bonding conductor is wrapped with insulating tape again between two cable sockets.In this case, if whole insulator only is made of the polypropylene insulation band, the so manual polypropylene insulation band that takes up innermost layer is very difficult.Otherwise contemplated as the present invention when insulator alternately is entwined by polypropylene film and brown paper, by twining brown paper, the primary insulation band can be tightened at an easy rate.And intraformational bed tightly can keep by brown paper easily around state.Like this, alternately be wound with the work that continues that is beneficial to cable, and stabilized and increased the quality of cable connection part.All of these factors taken together has all improved the insulator machinery and the electrical characteristic of cable of the present invention.
Only from electric viewpoint, plastic film, its arrangement that lacks polarity group and its carbon and hydrogen atom is very regular, therefore is being inferior to the brown paper that contains polarity group and carbon and hydrogen atom random distribution slightly aspect corona discharge and the electric leakage stoping.The reason of this difference still remains to be clarified.This tendency is particularly remarkable with regard to anti-pulse strength, particularly to anti-positive pulse intensity, result as big quantity research, the present inventor finds brown paper of the present invention and cooperating of polypropylene film to show significant characteristic, and this is because brown paper produces equally distributed barrier interface in insulating interlayer.This discovery has caused having the generation of good electric strength cable.
From the viewpoint of material cost,, be still the twice of brown paper price even as the polypropylene film of one of quite cheap plastic material.Like this, with respect to regard to the characteristic of dielectric constant (ε) and loss tangent (tan δ), cooperate the ratio of heifer paper to increase the economical and practical further improvement of cable with polypropylene film with regard to cable with brown paper.
Like this, cable of the present invention has and alternately twines brown paper and polypropylene film, shows its significant benefit to greatest extent.
Now, with reference to description of drawings working example of the present invention.Figure-1A is the schematic diagram of insulating interlayer winding operation.Insulating interlayer is made up of many layers.Fig. 2 is the cross section that is wrapped in the oil immersion insulator on the conductor, and label 1 is represented cable core, 2 expression conductors, 3 expression insulators, the 4th, the aluminium or the plumbous metal armouring of parcel oil immersion insulator, the 5th, the anticorrosion overcoat of covering armouring 4.
A kind of scheme of alternately twining is shown in figure-1B.Figure-1B is explanation typical case's insulation of the present invention
The cross section of body structure, this figure amplify the Z part of having described cross section among the figure-2.Specifically, figure-1B has represented a kind of scheme of insulator structure of the present invention, insulating barrier group repeated arrangement in whole insulating interlayer of being made up of one deck polypropylene film 3a and one deck brown paper 3b in this structure.Because the ratio of the polypropylene film and the brown paper number of plies is about 1: 1 in this structure, the ε .tan δ value of whole cable is between these the two kinds of corresponding ε .tan of material δ values.Because ratio is 3.4 * 0.2% concerning brown paper, and polypropylene film is about 2.2 * 0.02%, therefore the total Ztan δ value of whole cable equals 2.8 * 0.1%.For this structure, only use the traditional cable of brown paper to compare with insulator, dielectric loss decline (approximately to (2.8 * 0.1%)/(3.4 * 0.2%)=0.41).Therefore, cable of the present invention proves the extra-high voltage grade that the utmost point is applicable to 275～500KV.
Because this structure has the brown paper that good buffering usefulness can be provided, every lamella mulberry paper is between adjacent two polypropylene layers, and the thickness that it can easily adapt to any polypropylene film that causes because of expansion increases.This structure is produced and is very easy to, and this is because it gives the enough allowance of surface coarsening of brown paper and polypropylene film, and allows to control easily the elasticity that insulating tape twines.Even for the pliability and other mechanical property of the cable of finishing, brown paper demonstrates good this fact of buffering usefulness, also is very desirable advantage.Furtherly, because brown paper is inserted between adjacent two polypropylene films and with such method and is distributed in the whole insulator, one wall effect is provided, in fact aspect electric breakdown strength, there is not any loss, specifically, has the positive pulse breakdown strength that heavily stressed conductor one side of positive polarity measures.This structure has also been eliminated the thickness effect of plastic film, and the thickness effect of film is meant the effect of the breakdown strength decline that occurs when the thickness of interlayer of only being made by polypropylene film increases.Therefore, also more outstanding on electric with the cable of this insulator structure.
As mentioned above, the cable of figure-1B insulator structure all is stable and good in electric and mechanical aspects.Therefore, its high superhigh pressure level that is pressed onto of being suitable for 275-1000KV is used.
For further reduce dielectric loss (dielectric loss be proportional to transmission voltage square and ε .tan δ), require cable to have lower ε .tan δ value.For satisfying this requirement, the present invention
The person correspondingly designs the insulator structure that is shown in figure-1C.More precisely, in this structure, each insulating barrier group is made up of two layers of polypropylene film 3a and one deck brown paper 3b that is inserted into wherein, and the insulating barrier group is repeated arrangement in whole insulator.In this insulator structure, corona discharge and leakage current resistance that brown paper has the barrier generation of good buffering usefulness, brown paper are good.In the cable that uses this insulator structure, dielectric constant (ε) is that (2 * 2.2+3.4)/3=2.6, dielectric loss tangent (tan δ) is (2 * 0.02%+0.2%)/3=0.087%.Like this, the ε .tan δ value of this cable is compared comparatively (2.6 * 0.087)/(3.4 * 0.2)=0.33 with the cable of only making insulating interlayer with brown paper.Therefore, do not sacrifice actually under the condition of other machinery and electrical characteristic, this cable has obtained reducing of desired dielectric loss.
In this insulator structure, since as the mixing ratio of the brown paper of buffer portion simultaneously local and all be reduced to 2/3rds of figure-1B structure on the whole, therefore be necessary to increase a little the surface roughness of polypropylene film above-mentioned and brown paper, use lower winding pulling force simultaneously.However, because all polypropylene films adjoin in brown paper, and therefore maximally utilised the buffering usefulness of brown paper, from the processing and the flexible nature of cable, it is very suitable that the cable of producing proves.
From electric viewpoint,,, kept the wall effect of brown paper and to the resistance of corona discharge and leakage current as desirable though cable is being suffered a loss aspect the positive pulse intensity slightly.
Contain the thick brown paper of water in air branch or utilize additional water to make its thickness brown paper of the humidity regulation of increase in advance by use, and need not be lower than the brown paper of the drying below 1% as the humidity of manufacturing the insulating interlayer that only contains brown paper, then the buffering effect of brown paper can obtain better, not as twining dry brown paper, require special warehouse, the wrapping machine that specialized designs can be twined under drying regime for the additional process of dry brown paper, maintenance brown paper drying.The contemplated winding of the present invention carry out easily and appropriate litigation fees cheap.
The present inventor has further improved the breakdown characteristics of cable, and method is as follows.Specifically, the present inventor to find to use the brown paper with high-k and high corona resistance be highly desirable
, utilize this skill, under the damaed cordition of the discernable rising of ε .tan δ that does not suffer whole cable, particularly the positive pulse intensity of cable can improve.
Fig. 3 is the perspective view of oil immersion insulator in the oil immersion insulated cable, the dual oil clearance 8 of intersection that has demonstrated oil clearance simultaneously and formed between two insulating tapes of adjacent interlayer.In the drawings, 6 refer to (left hand to) oil immersion insulating interlayer of internal layer, the 7th, outer field (right hand to) oil immersion insulating interlayer, and 8 be the zone that takes place of interlayer staggered (change of insulating tape direction) and herein the degree of depth of oil clearance equal the thickness of two-layer insulating tape.This special part has constituted another weak spot of cable.
For remedying this weak spot, as shown in Figure 4, label 6a represents inner insulation layer, 7a represents outer insulation, the present invention is being subjected to oil immersion insulating interlayer alternating share 8a(Fig. 4 arrow indication part certainly, and the oil clearance degree of depth equals the thickness of two-layer insulating tape herein) use the brown paper insulating tape on the level of influence, make any partial breakdown at oil clearance 8a place, because the wall effect of brown paper can not develop the puncture of whole cable rapidly.In Fig. 4, layer of polypropylene foil serves as the adjoining course of interlayer alternating share, and selectively, these two adjoining courses also can constitute with brown paper, make always to have four layers of brown paper, interlayer alternately point each is two-layer up and down.It is quite effective that this structure has been proved to be.At the staggered position of the interlayer at close conductor one side electric stress marking area place, the configuration layers of kraft paper is more efficiently.The mixing ratio that reduces brown paper in hope to be to reduce the occasion of ε .tan δ value, and only to adopt this method be useful to the alternating share in five of the most close conductor edge or still less interlayer.
Especially about the decline of positive pulse intensity, this will give suitable attention to use the occasion of polypropylene film in cable, can improve significantly by configuration brown paper.These improve the effectiveness that has increased cable of the present invention greatly.
The polypropylene film that the present invention is contemplated and the surface roughness of brown paper are with the variation of electric pressure, conductor size, type of cable and used insulating oil and marked change.It also is subjected to the influence of the concrete combination of polypropylene film and insulating oil especially.
In cable of the present invention, the combination of polypropylene film and detergent alkylate has been proved to be able to make cable to obtain excellent electric characteristics, although other insulating oil can draw good effect too.For example, usually use the polybutene class insulating oil of high viscosity to polymerization oil compression cable (POF).
When using this class insulating oil, because the swell increment of polypropylene film is little, the boss that therefore needs only formation 2-10 micron on the brown paper used in Figure 1A insulator structure is just enough.Certainly, in the other type, it is just enough only to form about 5 microns boss on polypropylene film.Under the situation of the figure-1B insulator structure that relates to the combination of polypropylene film and detergent alkylate, as long as accomplish on all polypropylene film sheets, to form the boss of 6-20 micron, or at the boss that forms the 20-40 micron on one deck layer of polypropylene foil, it is just enough that perhaps the boss that forms the 5-10 micron in all layer of polypropylene foil forms 1～5 micron the situation of boss simultaneously on the brown paper scraps of paper of place.Even the same, also might determine to run through the optimal values of the adjacent interband internal pressure on the whole insulator by the level of tightness that control insulating tape width and control insulating tape twine with the boss of combinations thereof.
The appropriateness of this internal pressure can be made by the following method, and a given cable was kept 24 hours in maximum operating temperature (for example 85 °～95 ℃) environment, and the polypropylene film band is expanded fully.Then, secondary curves diameter with cable and approximates the twentyfold ring of insulator outermost layer diameter back and forth, cuts the insulating tape degree of impairment in cable and the macroscopic examination insulator then.
Under any circumstance, necessary according to cable, the type of insulating tape and insulating oil selected surface roughness in 1～50 micron scope is adjusted the winding condition of insulating paper (insulating tape) simultaneously to make cable corresponding to selected surface roughness.In case cables manufacturing finishes, often be necessary in the maximum operating temperature environment of cable, to make the polypropylene film band to expand, the cable that has expanded is implemented bend test, then check the quality of cable insulation.
The present invention is by providing a cable, and the polypropylene film density value of this cable, birefringence, two axial strength ratios and surface roughness are in corresponding specified scope; Polypropylene film and brown paper in this cable, one or both, reach following notable feature at single or double, suitably alligatoring:
(1) cable expands minimum with insulating oil;
(2) insulating oil mobile satisfactory between insulating tape lap part;
(3) cable insulation (insulating interlayer) presents remarkable mechanical property and have gratifying machinability in the insulating tape winding process;
(4) being wrapped in insulating tape on the conductor promptly is difficult for pine and also is difficult for tight;
(5) it is easy and formed insulating interlayer is solid and reliable to twine insulating tape in two cable socket joint portions;
(6) can make cable according to the polypropylene film of any requirement selection and the combination of brown paper, thereby can not sacrifice dielectric constant and the dielectric loss angle tangent that provides required under the economical and practical condition;
(7) cable dielectric good strength, particularly good aspect pulse strength.
Be used for test mode of the present invention, method is described below:
(1) isotacticity:
From the normal heptane of boiling, extract one and specify the polypropylene sample.The weight of the residue after the extraction is divided by the original weight of sample, and its merchant multiply by 100, and the long-pending of gained is the isotacticity of representing with percentage.
(2) melt index (MI):
This physical characteristic is measured under American Standard of Testing Materials D-1238-73 condition L instructs.
(3) melt crystallization temperature (Tmc):
One weight is that 5 milligrams sample places a test apparatus, and the DSC-II type test instrument made of Perkins Ai Ermo company is for example discharged air in the instrument with nitrogen.After this, sample is heated to 200 ℃, under these 200 ℃ of ranks, kept 5 minutes then with the speed of 20 ℃/per minute.With of the speed cooling of hot sample, during this period, make instrument depict the heat crest that is sent as the sample crystallization of fusing again with 20 ℃/per minute.The temperature of the hump of describing is designated as TmC.
(4) density;
This characteristic is tested with reference to American Standard of Testing Materials D-1505.
(5) birefringence:
Utilize a chromatic dispersion refractometer, measure the longitudinal refractive index (N of given film sample
y) and laterally
Refractive index (N
x).N
yDeduct N
xThe gained difference is birefringence.In this measurement, sodium D-ray be used as light source and gaultherolin as pasting media.
(6) two axial strength ratios:
The endwise tensile strength σ of film sample
y(kilogram/square millimeter) and transverse tensile strength σ
x(kilogram/square millimeter) measured with the method for American Standard of Testing Materials D-882-67.σ
yDivided by σ
cThe quotient representation strength ratio of gained.
(7) surface roughness (Rmax):
The roughness Rmax of film sample measures with the described method of the B-0601-1976 of Japanese Industrial Standards, and cutoff value is due to 0.5 millimeter.
(8) pyrocondensation ratio:
From the sample of 10 millimeters of sample film intercepting one long 200 mm wides, vertically getting of sample done the direction of measuring ratio.Sample had in the heating chamber of 120 ℃ of hot-airs in circulation kept 15 minutes.After this, sample is moved apart heating chamber, measures with the length that this determination method reached, pyrocondensation compare by under the definition that establishes an equation:
Pyrocondensation is than (%)=100 * (200-L)/200
(9) cable insulation is with the swell increment of insulating oil:
The lamination that 30 millimeters * 30 millimeters samples of institute's requested number are formed places pressure to be about under 1 kilogram/every square centimeter the spring pressure.The thickness of web-like lamination is designated as t
1In this state, a desired degree that lamination is dried then is dipped in the insulating oil.Then be heated the temperature that to test, for example 85 °～95 ℃, keep this temperature polypropylene film to be expand into to greatest extent in 4-24 hour.Laminated thickness note after the complete expansion is made t
2, then swell increment (%) obtains according to following equation:
Swell increment (%)=100 * (t
1-t
2)/(t
2)
(10) flowability of insulating oil:
One film sample twines to make a cable around conductor.This cable is dipped in the insulating oil, then is under the vacuum state with insulating oil.After this, cable taken apart and macroscopic examination judging whether insulating oil has been diffused in all interlayer gaps of film, measure that to formulate justice as follows for three grades:
Grade A: insulating oil fully and equably be diffused into the institute gapped in.
Grade B: have the inadequate a little indivedual points of oil diffusion.
Grade C: have the face that oil is not diffused into fully.
Be used as the oil immersion insulating material, require film to belong to grade A.In the application of low-voltage cable, the film that belongs to the B level also is acceptable.The film that belongs to grade C can not be used as the oil immersion insulating material.
(11) electric insulation oil:
This is a common name that is applicable to all known electric insulation oil plants, as mineral oil, castor oil, cotton seed oil, alkyl benzene, diallyl alkane, polybutene lubricating oil, oxosilane oil.
With reference to example and comparative example, the present invention will more specifically be described below:
Some are had the regular content 97.6% of isotaxy, melt index (MI) 6 gram/10 minutes, the acrylic resin bead that the melt crystallization temperature is 110.5 ℃ is put into extruder, and melt is that 260 ℃ T shape mould extruding is sheet by temperature.The melt sheet material is wrapped in a temperature to be on 30 ℃ the cooling axle and to make its cooling curing, to produce the sheet material that thickness is about 1000 microns.This sheet material by one group of rolling roller bearing (shaft diameter is 250 millimeters) rolling for about nine times to the sheet material of raw footage.At rolling pressure is 500/ kilograms per centimeter, and rolling axle temperature degree is 140 ℃ and is rolled.Sheet surface squirts with polyethylene glycol.The thickness that rolls out is about 90 microns film, and to send into a temperature be to stand the heat treatment in 10 seconds in 130 ℃ the environment, make film loosen 1% in the vertical, after this, film stamps the sand blasting pattern that roughness is 100 screen sizes by being in 130 ℃ embossing roller bearing with two surfaces at film.The film that is in tensioned state keeps 10 hours with the heat treatment of wearing out in temperature is 120 ℃ environment.After this, make its cool to room temperature temperature gradually.This film is cut into the insulating tape of 22 mm wides.
The characteristic that this polypropylene film presented is as follows:
Density (gram/cubic centimetre) 0.910
Birefringence 0.030
Two axial strength ratios 10.2
Pyrocondensation is than (%) 1.3
Surface roughness (Rmax) (micron) 12.5
Swell increment (%) 3.1
Polypropylene film average thickness (micron) 100
As a comparison, to having bought the same characteristic of polypropylene film test of non-stretch-draw polypropylene film and biaxial orientation on the market, the result is as follows:
Poly-third of non-stretch-draw polypropylene film biaxial orientation
The alkene film
Density 0.899 0.905
Birefringence 0.003 0.013
Two axial strength ratios 4.3 1.9
Pyrocondensation is than (%) 0 2.8
Surface roughness (Rmax) (micron) 0.6 0.9
Plane polypropylene film at 80 ℃
Swell increment (%) 11.6 6.3
The brown paper characteristic that is used with polypropylene film is as follows:
Density (gram/cubic centimetre) 0.80
Tightness (Gurley.sec) about 3000
Thickness (micron) 100
Width is 22 millimeters an ox-hide paper tape, with the pointed different structure of following table 1, at sectional area be on 200 square millimeters the twisted wire conductor mutually overlap joint 1/3rd twine.Resulting cable is at first dried and is then at room temperature immersed detergent alkylate, then keeps 48 hours so that polypropylene film thoroughly expands in 100 ℃ of temperature.Allow cable be cooled to normal room temperature, come back bending to move twice, form the ring that diameter approximates 20 times of insulating barrier diameters.At last, take the state of cable macroscopic examination insulating barrier apart.
From these results, it should be noted that the insulator made according to the present invention is by twining the insulating tape that expansion is only arranged slightly with insulating oil, demonstrate good fluidity and good bendability thereof to insulating oil, has high anti-pulse strength, has only minimum positive pulse loss of strength, allow the ε .tan δ value that reaches required, thereby to be used for production oil immersion insulated power cable be very useful.
As what above mentioned, the present inventor successfully utilizes the particular combination of polypropylene film and brown paper to make to have quality, the oil-immersed type power cable of high practicability.
Yet as previously mentioned, the factor that reduces the wastage (ε .tan δ) is subjected to the restriction of brown paper total amount.For the factor that reduces the wastage, must use the brown paper that is thinner than 70 microns (lower limits of individual layer brown paper thickness) to reduce insulator heifer paper total amount.Based on above-mentioned reason, this is worthless.Yet according to the present invention, a kind of thin brown paper can use jointly with polypropylene film.The polypropylene film that uses jointly with thin brown paper should be the film of low bulk, and it is squeezed between two thin brown paper by melt.Such brown paper all is being good aspect buffering effect and the insulation characterisitic.Specifically, two-layer brown paper sandwiches the melt extruded polypropylene film of low bulk degree, forms a multilayer (being three layers) lamination (being called the polypropylene layer platen) here, is used for replacing brown paper.Table-2 illustrates the example of explanation polypropylene layer platen:
Table-2
Sample lamination A B C
Gross thickness (micron) 125 155 200
Polypropylene thickness (micron) 45 55 80
Brown paper thickness (micron) 40.40 40.60 60.60
Density (gram/cubic centimetre) 0.88 0.90 0.90
Dilation in the time of 100 ℃ (%) 4.0 3.8 3.3
ε 2.75 2.79 2.81
tanδ（%） 0.07 0.08 0.09
The ε .tan δ value of supposing the polypropylene layer platen is 2.8 * 0.1%, and insulator for the ε .tan δ value of alternately twining the made cable of polypropylene film and polypropylene layer paper is:
[（2.2+2.8）/2]·[（0.02%+0.1%）/2]＝2.5×0.06%
Insulator is for twining the made cable of combination of a slice polypropylene layer platen and two polypropylene films, and its ε .tan δ value is:
[（2.2×2+2.8）/3]·[（0.02%×2+0.1%）/3]＝2.4×0.047%
The ratio of the cable ε .tan δ value that above-mentioned value and insulator only are made up of brown paper is respectively:
（2.5×0.06）/（3.4×0.2）＝0.22
（2.4×0.047）/（3.4×0.2）＝0.17
Be clear that from these ratios, use polypropylene layer platen of the present invention to reduce the loss in the cable significantly.
Table-3 has provided the comparing data of insulating barrier by the cable that constitutes of polypropylene film and polypropylene layer platen.In table-3, No. 1 sample is identical with No. 1 sample in the table 1.
Be clear that very that from table-3 No. 10 samples and No. 11 coupon results show that this class cable is practical.On the basis of No. 10 or No. 11 samples, produce cable, be necessary with surface coarsening to 20～40 micrometer ranges of polypropylene film or with surface coarsening to 5～10 micrometer ranges of polypropylene film, simultaneously with surface coarsening to 3～10 micrometer ranges of polypropylene layer platen, and the pulling force that twines the required control of insulating tape is inappreciable.
Another embodiment of the present invention is shown in figure-5, by using a kind of what is called " ε-hierarchy system ", wherein the part of the minor insulation body 11 of contiguous conductor 10 has the ε value, it reduces with the distance increase of distance conductor, make the strong stress that produces around the ac cable conductor 10 can reduce to minimum, with the further dielectric breakdown strength that improves its insulator.According to present embodiment, the gross thickness of insulation can correspondingly reduce, and the size of cable can reduce like this.Gross thickness by reducing insulating barrier with the size that reduces cable with reduce ε .tan δ value no less important.Particularly all the more so to the cable that is used for extra-high voltage or superhigh pressure.
In figure-5, insulator is made up of five local delamination 11-15, wherein minor insulation layer 11 is made of brown paper, minor insulation layer 12 is alternate combinations of brown paper and polypropylene film, the 13rd, the alternate combinations of one deck brown paper and two polypropylene films, the 14th, the alternate combinations of one deck polypropylene layer platen and one deck polypropylene film, the 15th, the alternate combinations of one deck polypropylene layer platen and two layers of polypropylene film.
Table 3
Test piece number (Test pc No.) 1 10 11
The rolling polypropylene of polypropylene that insulating tape brown paper is rolling
Film and with poly-third film and laminated paper
The paper of alkene lamination
It is the same that sample structure (1) contains 6 layerings (1) the same (1)
Individual layer (2) (2)
The polypropylene paper of polypropylene (3) lamination of (2) 3 layers of (3) lamination
Paper and polypropylene are thin and two layers of polypropylene is thin
The alternate combinations film alternate combinations of film
ε 3.4 2.52 2.43
tanδ（%） 0.23 0.055 0.049
Reverse impulse 1.0 1.9 1.8
Direct impulse 0.95 1.4 1.4
The mobile A A A of insulating oil
The truncation test result does not have difference " "
Table-4 has shown the data of typical ε classification cable shown in the figure-5:
Table-4
Minor insulation layer structure ε .tan δ (%)
Number side 11 brown paper 3.4 * 0.2
12 one deck brown paper and one deck roll
That makes polypropylene film replaces 2.8 * 0.1
Assembly
13 one deck brown paper and two-layer rolling
That makes polypropylene film replaces 2.6 * 0.087
Assembly
14 one decks-polypropylene layer platen and one deck
The alternate combinations 2.5 * 0.06 of rolling polypropylene film
Body
15 one deck polypropylene layer platens of insulator and two-layerly roll 2.4 * 0.047
The alternate group zoarium of outer surface system polypropylene film
In table 4, brown paper, the dielectric loss of polypropylene layer platen and paper expansioning polypropylene film of the present invention (ε .tan δ) is approximately 3.4 * 0.2%, 2.8 * 0.1% and 2.2 * 0.02% respectively.According to the grade of cable, if necessary, one or more local delamination can be omitted in the minor insulation layer 11～15 in table 4.
ε graded insulation cable of the present invention dielectric breakdown voltage with respect to the cable that does not contain the ε classification has improved 3%～10%.
As indicated above, according to insulation oil immersion power cable of the present invention, this cable uses the polypropylene film of being invented with low bulk and good mechanical properties, brown paper or the polypropylene layer platen that natural polar material is made, one of them part is through alligatoring, at least a portion as its insulator, present in dielectric loss dielectric breakdown voltage, the remarkable improvement of miniaturization and reliability aspect.
Claims (47)
1, a kind of power cable, it comprises:
Conductor;
Insulator around above-mentioned conductor, constituting by on above-mentioned conductor, twining polypropylene film to small part of above-mentioned insulator, and the insulating oil that is used to flood above-mentioned insulator, the density of polypropylene film that it is characterized in that described conductor is in 0.905-0.915 gram/cubic centimetre scope, birefringence is in the 0.020-0.035 scope, the ratio of endwise tensile strength and transverse tensile strength is in the 5-15 scope, and thickness is in the 70-300 micrometer range.
According to the power cable of claim 1, it is characterized in that 2, above-mentioned insulator also comprises brown paper, this brown paper and above-mentioned polypropylene film respectively are wound on the above-mentioned conductor.
According to the power cable of claim 2, it is characterized in that 3, the smallest group zoarium that respectively twines polypropylene film and brown paper is the combination of one deck polypropylene film and one deck brown paper.
According to the power cable of claim 2, it is characterized in that 4, the smallest group zoarium that respectively twines polypropylene film and brown paper is the combination of two layers of polypropylene film and one deck brown paper.
5, according to the power cable of claim 2, it is characterized in that, above-mentioned polypropylene film of at least a portion and brown paper, the part surface roughness of its single or double is in the 1-50 micrometer range.
According to the power cable of claim 2, it is characterized in that 6, above-mentioned brown paper comprises coarse brown paper.
According to the power cable of claim 2, it is characterized in that 7, above-mentioned brown paper comprises through limiting moist thick brown paper.
According to the power cable of claim 2, it is characterized in that 8, above-mentioned insulating oil comprises detergent alkylate.
9, according to the power cable of claim 2, it is characterized in that, above-mentioned cable will be in the maximum operating temperature that requires before transportation through 24-48 hour heat treatment.
According to the power cable of claim 1, it is characterized in that 10, above-mentioned insulator comprises many insulating interlayers, this insulating interlayer comprises the combination of brown paper and polypropylene film.
According to the power cable of claim 10, it is characterized in that 11, the innermost layer interlayer of above-mentioned interlayer comprises the above-mentioned brown paper of 3-10 layer.
12, according to the power cable of claim 10, it is characterized in that, in five interlayers of innermost layer, alternate interlayer is that rightabout twines, and, the gap location that forms between the wherein adjacent interlayer intersection point of described interlayer, the insulating barrier that the side is adjacent to this gap constitutes with above-mentioned brown paper.
13, according to the power cable of claim 1, it is characterized in that, above-mentioned insulator also comprises insulating paper lamination material, above-mentioned laminated material comprises that two-layer insulating paper and the fusion pressure one deck polypropylene adhesion layer between above-mentioned two-layer insulating paper is bonding, and this laminated material and above-mentioned polypropylene film respectively are wound in above-mentioned conductor.
According to the power cable of claim 13, it is characterized in that 14, the smallest group zoarium of alternate winding polypropylene film and above-mentioned laminated material is the combination of one deck polypropylene film and the above-mentioned laminated material of one deck.
According to the power cable of claim 13, it is characterized in that 15, the smallest group zoarium of alternate winding polypropylene film and above-mentioned laminated material is the combination of two layers of polypropylene film and the above-mentioned laminated material of one deck.
16, according to the power cable of claim 13, it is characterized in that, above-mentioned polypropylene film of at least a portion and above-mentioned laminated material, the part surface roughness of its single or double is in the 1-50 micrometer range.
According to the power cable of claim 13, it is characterized in that 17, above-mentioned laminated material comprises thick laminated material.
According to the power cable of claim 13, it is characterized in that 18, above-mentioned laminated material comprises through limiting moist laminated material.
According to the power cable of claim 13, it is characterized in that 19, described insulating oil comprises detergent alkylate.
20, according to the power cable of claim 13, it is characterized in that, before the transportation of above-mentioned cable in the maximum operating temperature of estimating through 24-48 hour heat treatment.
According to the power cable of claim 13, it is characterized in that 21, above-mentioned insulator comprises many interlayers, above-mentioned each interlayer comprises the multilayer insulation band.
According to the power cable of claim 14, it is characterized in that 22, above-mentioned insulator also comprises brown paper.
According to the power cable of claim 22, it is characterized in that 23, the innermost layer of above-mentioned insulator comprises the above-mentioned brown paper of 3-10 layer.
24, according to the power cable of claim 10, it is characterized in that, in five interlayers of innermost layer, interlayer alternately twines in opposite directions, and, the gap location that between the adjacent interlayer intersection point of above-mentioned interlayer, forms, the insulating barrier that the side is adjacent to this gap constitutes with above-mentioned brown paper.
25, a kind of power cable, it comprises:
Conductor;
Insulator around above-mentioned conductor formation, and the insulating oil that is used to flood above-mentioned insulator, it is characterized in that this insulator comprises the insulating interlayer of internal layer, the insulating interlayer in middle level, and outer field insulating interlayer, described insulating interlayer has different dielectric constants makes the dielectric constant of above-mentioned insulator change gradually, has maximum numerical value at the insulating barrier place of above-mentioned internal layer, and with distance increase apart from this conductor, dielectric constant reduces successively, at least above-mentioned outer field insulating interlayer comprises polypropylene film, the density of polypropylene film is in 0.905-0.915 gram/cubic centimetre scope, birefringence is in the 0.020-0.035 scope, and the ratio of endwise tensile strength and transverse tensile strength is in the 5-15 scope, and thickness is in the 70-300 micrometer range.
According to the power cable of claim 25, it is characterized in that 26, above-mentioned insulator also comprises brown paper.
According to the power cable of claim 26, it is characterized in that 27, the insulating interlayer of the innermost layer of above-mentioned insulator comprises the above-mentioned brown paper of 3-10 layer.
28, according to the power cable of claim 27, it is characterized in that, in five insulating interlayers of above-mentioned insulator innermost layer, interlayer alternately twines in opposite directions, and, the gap location that forms between the adjacent interlayer intersection point of above-mentioned interlayer, the insulating barrier that the side is adjacent to above-mentioned gap constitutes with above-mentioned brown paper.
According to the power cable of claim 27, it is characterized in that 29, above-mentioned brown paper comprises thick brown paper.
According to the power cable of claim 27, it is characterized in that 30, above-mentioned brown paper comprises through limiting moist thick brown paper.
According to the power cable of claim 25, it is characterized in that 31, above-mentioned insulating oil comprises detergent alkylate.
32, according to the power cable of claim 25, it is characterized in that, before the transportation of above-mentioned cable in the maximum operating temperature of estimating through 24-48 hour heat treatment.
33, according to the power cable of claim 25, it is characterized in that, the insulating interlayer of above-mentioned internal layer constitutes with brown paper, this outer field insulating interlayer constitutes with the alternate combinations of two layers of polypropylene film and one deck insulating paper lamination material, wherein insulating paper lamination material comprises above-mentioned two-layer insulating paper and the molten single-layer polypropylene adhesion layer bonding that is pressed between the above-mentioned two-layer insulating paper, and above-mentioned laminated material and above-mentioned polypropylene film alternately are wound in this conductor.
According to the power cable of claim 33, it is characterized in that 34, the insulating interlayer in above-mentioned middle level comprises the alternate combinations of one deck brown paper and the above-mentioned polypropylene film of one deck.
According to the power cable of claim 33, it is characterized in that 35, the insulating interlayer in above-mentioned middle level comprises the alternate combinations of one deck brown paper and two layers of polypropylene film.
According to the power cable of claim 33, it is characterized in that 36, the insulating interlayer in above-mentioned middle level comprises the alternate combinations of one deck polypropylene film and the above-mentioned laminated material of one deck.
37, according to the power cable of claim 33, it is characterized in that, the insulating interlayer in above-mentioned middle level comprises first, second and the 3rd insulating interlayer, above-mentioned first insulating interlayer comprises the alternate combinations of one deck brown paper and one deck polypropylene film, above-mentioned second insulating interlayer comprises the alternate combinations of one deck brown paper and two layers of polypropylene film, above-mentioned the 3rd insulating interlayer comprises the alternate combinations of one deck polypropylene film and the above-mentioned laminated material of one deck, and wherein laminated material is made of two-layer brown paper and one deck polypropylene film of being clipped between this brown paper.
38, according to the power cable of claim 32, it is characterized in that, above-mentioned at least brown paper, at least one surperficial at least a portion of one of above-mentioned polypropylene film and this laminated material, its surface roughness is in the 1-50 micrometer range.
39, according to the power cable of claim 25, it is characterized in that:
Around the insulator that above-mentioned conductor constitutes, according to being arranged in order from the outside order of above-mentioned conductor, this insulator comprises the interlayer that contains one deck laminated material and one deck polypropylene film, and the interlayer that contains one deck laminated material and two layers of polypropylene film.
40, according to the power cable of claim 25, it is characterized in that:
Around the insulator that above-mentioned conductor constitutes, according to being arranged in order from the outside order of above-mentioned conductor, this insulator comprises the interlayer that contains one deck brown paper and two layers of polypropylene film, and the interlayer that contains one deck laminated material and one deck polypropylene film.
41, according to the power cable of claim 25, it is characterized in that:
Around the insulator that above-mentioned conductor constitutes, according to being arranged in order from the outside order of above-mentioned conductor, this insulator comprises the interlayer that contains one deck brown paper and one deck polypropylene film, and the interlayer that contains one deck brown paper and two layers of polypropylene film.
42, according to the power cable of claim 25, it is characterized in that:
Insulator around above-mentioned conductor formation; According to being arranged in order from the outside order of above-mentioned conductor, this insulator comprises the interlayer that contains one deck brown paper and two layers of polypropylene film, contains the interlayer of one deck laminated material and one deck polypropylene film, and contains one deck laminated material and two layers of polypropylene film.
43, according to the power cable of claim 25, it is characterized in that:
Insulator around above-mentioned conductor formation, according to being arranged in order from the outside order of above-mentioned conductor, this insulator comprises the interlayer that contains one deck brown paper and one deck polypropylene film, contain the interlayer of one deck brown paper and two layers of polypropylene film, and the interlayer that contains one deck laminated material and one deck polypropylene film.
44, according to the power cable of claim 25, it is characterized in that:
Insulator around above-mentioned conductor formation, according to being arranged in order from the outside order of above-mentioned conductor, this insulator comprises the interlayer that contains one deck brown paper, contains the interlayer of one deck brown paper and one deck polypropylene film, and the interlayer that contains one deck brown paper and two layers of polypropylene film.
45, according to the power cable of claim 25, it is characterized in that:
Insulator around above-mentioned conductor formation, according to being arranged in order from the outside order of above-mentioned conductor, this insulator comprises the interlayer that contains one deck brown paper and one deck polypropylene film, the interlayer that contains one deck brown paper and two layers of polypropylene film, contain the interlayer of one deck laminated material and one deck polypropylene film, and the interlayer that contains one deck laminated material and two layers of polypropylene film.
46, according to the power cable of claim 25, it is characterized in that:
Insulator around above-mentioned conductor formation, according to being arranged in order from the outside order of above-mentioned conductor, this insulator comprises the interlayer that contains one deck brown paper, the interlayer that contains one deck brown paper and one deck polypropylene film, contain the interlayer of one deck brown paper and two layers of polypropylene film, and the interlayer that contains one deck laminated material and one deck polypropylene film.
47, according to the power cable of claim 25, it is characterized in that:
Insulator around above-mentioned conductor formation, according to being arranged in order from the outside order of above-mentioned conductor, this insulator comprises the interlayer that contains one deck brown paper, contains the interlayer of one deck brown paper and one deck polypropylene film, and the interlayer that contains one deck laminated material and one deck polypropylene film.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 85107046 CN1007296B (en) | 1985-09-25 | 1985-09-25 | Electric power cable |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 85107046 CN1007296B (en) | 1985-09-25 | 1985-09-25 | Electric power cable |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN85107046A CN85107046A (en) | 1987-04-08 |
| CN1007296B true CN1007296B (en) | 1990-03-21 |
Family
ID=4795418
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 85107046 Expired CN1007296B (en) | 1985-09-25 | 1985-09-25 | Electric power cable |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1007296B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2512803B1 (en) * | 2009-12-16 | 2013-10-23 | Prysmian S.p.A. | High voltage direct current cable having an impregnated stratified insulation |
| CN104934162B (en) * | 2015-06-09 | 2016-10-12 | 铜陵华洋特种线材有限责任公司 | The lubricating process of enamel-covered wire |
-
1985
- 1985-09-25 CN CN 85107046 patent/CN1007296B/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| CN85107046A (en) | 1987-04-08 |
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