CA1174307A - Above-ground conductor unit with corona noise reduction covering - Google Patents
Above-ground conductor unit with corona noise reduction coveringInfo
- Publication number
- CA1174307A CA1174307A CA000380865A CA380865A CA1174307A CA 1174307 A CA1174307 A CA 1174307A CA 000380865 A CA000380865 A CA 000380865A CA 380865 A CA380865 A CA 380865A CA 1174307 A CA1174307 A CA 1174307A
- Authority
- CA
- Canada
- Prior art keywords
- set forth
- hlb
- unit
- conductor unit
- mixture
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000004020 conductor Substances 0.000 title claims abstract description 60
- 230000009467 reduction Effects 0.000 title description 3
- 239000000203 mixture Substances 0.000 claims abstract description 25
- 239000006229 carbon black Substances 0.000 claims abstract description 3
- 239000000463 material Substances 0.000 claims description 22
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 claims description 4
- 229940035044 sorbitan monolaurate Drugs 0.000 claims description 4
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 3
- XZIIFPSPUDAGJM-UHFFFAOYSA-N 6-chloro-2-n,2-n-diethylpyrimidine-2,4-diamine Chemical compound CCN(CC)C1=NC(N)=CC(Cl)=N1 XZIIFPSPUDAGJM-UHFFFAOYSA-N 0.000 claims description 2
- HVUMOYIDDBPOLL-XWVZOOPGSA-N Sorbitan monostearate Chemical compound CCCCCCCCCCCCCCCCCC(=O)OC[C@@H](O)[C@H]1OC[C@H](O)[C@H]1O HVUMOYIDDBPOLL-XWVZOOPGSA-N 0.000 claims description 2
- 239000011810 insulating material Substances 0.000 claims description 2
- 229940070765 laurate Drugs 0.000 claims description 2
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N phenol group Chemical group C1(=CC=CC=C1)O ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 claims description 2
- 239000001587 sorbitan monostearate Substances 0.000 claims description 2
- 229940035048 sorbitan monostearate Drugs 0.000 claims description 2
- 235000011076 sorbitan monostearate Nutrition 0.000 claims description 2
- 125000005037 alkyl phenyl group Chemical group 0.000 claims 1
- 235000014113 dietary fatty acids Nutrition 0.000 claims 1
- POULHZVOKOAJMA-UHFFFAOYSA-M dodecanoate Chemical compound CCCCCCCCCCCC([O-])=O POULHZVOKOAJMA-UHFFFAOYSA-M 0.000 claims 1
- 239000000194 fatty acid Substances 0.000 claims 1
- 229930195729 fatty acid Natural products 0.000 claims 1
- 150000004665 fatty acids Chemical class 0.000 claims 1
- 230000010148 water-pollination Effects 0.000 claims 1
- 238000005253 cladding Methods 0.000 abstract description 14
- 239000004033 plastic Substances 0.000 abstract description 14
- 229920003023 plastic Polymers 0.000 abstract description 14
- 229920001971 elastomer Polymers 0.000 abstract description 4
- -1 generally Substances 0.000 abstract description 2
- 239000011347 resin Substances 0.000 abstract 1
- 229920005989 resin Polymers 0.000 abstract 1
- 150000001875 compounds Chemical class 0.000 description 7
- 230000000694 effects Effects 0.000 description 6
- 150000002433 hydrophilic molecules Chemical class 0.000 description 5
- 230000005684 electric field Effects 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 2
- 230000008020 evaporation Effects 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 238000009413 insulation Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000005488 sandblasting Methods 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- 229920000459 Nitrile rubber Polymers 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- XTXRWKRVRITETP-UHFFFAOYSA-N Vinyl acetate Chemical compound CC(=O)OC=C XTXRWKRVRITETP-UHFFFAOYSA-N 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 239000003963 antioxidant agent Substances 0.000 description 1
- 235000006708 antioxidants Nutrition 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 235000019241 carbon black Nutrition 0.000 description 1
- 229940000425 combination drug Drugs 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000001066 destructive effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- RUZYUOTYCVRMRZ-UHFFFAOYSA-N doxazosin Chemical compound C1OC2=CC=CC=C2OC1C(=O)N(CC1)CCN1C1=NC(N)=C(C=C(C(OC)=C2)OC)C2=N1 RUZYUOTYCVRMRZ-UHFFFAOYSA-N 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000001788 mono and diglycerides of fatty acids Substances 0.000 description 1
- 235000019960 monoglycerides of fatty acid Nutrition 0.000 description 1
- 239000000088 plastic resin Substances 0.000 description 1
- 239000004014 plasticizer Substances 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 238000010183 spectrum analysis Methods 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
- 229940117958 vinyl acetate Drugs 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B5/00—Non-insulated conductors or conductive bodies characterised by their form
- H01B5/16—Non-insulated conductors or conductive bodies characterised by their form comprising conductive material in insulating or poorly conductive material, e.g. conductive rubber
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B7/00—Insulated conductors or cables characterised by their form
- H01B7/17—Protection against damage caused by external factors, e.g. sheaths or armouring
- H01B7/28—Protection against damage caused by moisture, corrosion, chemical attack or weather
- H01B7/282—Preventing penetration of fluid, e.g. water or humidity, into conductor or cable
- H01B7/285—Preventing penetration of fluid, e.g. water or humidity, into conductor or cable by completely or partially filling interstices in the cable
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A30/00—Adapting or protecting infrastructure or their operation
- Y02A30/14—Extreme weather resilient electric power supply systems, e.g. strengthening power lines or underground power cables
Landscapes
- Compositions Of Macromolecular Compounds (AREA)
- Insulated Conductors (AREA)
- Conductive Materials (AREA)
- Non-Insulated Conductors (AREA)
Abstract
ABOVE-GROUND CONDUCTOR UNIT WITH
CORONA NOISE REDUCING COVERING
ABSTRACT OF THE DISCLOSURE: An overhead conductor unit used for transmitting high voltage, alternating current, electrical energy which comprises one conductor or several metallic wires grouped together and a thin plastic cladding, a resin or resin-rubber, around the conductor or wires. The plastic cladding includes at least one conductive composition, generally, carbon black in an amount of 5-40 parts by weight and at least one hydrophilic composition present in 1-10 parts by weight. The thus obtained overhead conductor unit reduces, or prevents, corona noises when the unit becomes wet.
CORONA NOISE REDUCING COVERING
ABSTRACT OF THE DISCLOSURE: An overhead conductor unit used for transmitting high voltage, alternating current, electrical energy which comprises one conductor or several metallic wires grouped together and a thin plastic cladding, a resin or resin-rubber, around the conductor or wires. The plastic cladding includes at least one conductive composition, generally, carbon black in an amount of 5-40 parts by weight and at least one hydrophilic composition present in 1-10 parts by weight. The thus obtained overhead conductor unit reduces, or prevents, corona noises when the unit becomes wet.
Description
~ ~743~
The present invention relates to an overhead conduc-tor unit used for transmitting high voltage, alternating current (A.C.), electrical energy. In particular, it relates to a conductor comprising one conductor or a plurality of conductors grouped together and a thin plastic cladding there-around the unit having the characteristic of not emitting any noises, or at least, of emitting negligible noise, during rainfall or significant atmospheric humidity.
Overhead lines comprising bare conductors that are stretched between an appropriate pole system are well-known in the art. Said lines are generally used for the transmission of A.C. electrical energy having a high voltage (400-500kV).
Each conductor has a diameter of a few centimeters and can comprise a single tubular metallic body, or else, more fre-quently, several metallic wires grouped together.
Along the bare conductor, there is always manifested the so-called "corona effect" which is the ionization of the air in contact with the metallic surface under high voltage and which comprises a series of small electrical discharges. The "corona effect" is proportional to the field gradient existing around the conductor and hence, to the electrical tension applied. In the above-described conditions, the field gradient is around about 20kV/cm.
One of the consequences of the "corona effect" is the generation of noises. However, when the conductor is dry, noise generation is quite limited, and as for the disturbance effectively caused, it is practically negligible. On the contrary, when the conductor is wet, the noise is much more intense, and this is the source of significant disturbances which are irritating and annoying for passers-by and to those who are inhabitants of the immed~iate vicinity. Under these
The present invention relates to an overhead conduc-tor unit used for transmitting high voltage, alternating current (A.C.), electrical energy. In particular, it relates to a conductor comprising one conductor or a plurality of conductors grouped together and a thin plastic cladding there-around the unit having the characteristic of not emitting any noises, or at least, of emitting negligible noise, during rainfall or significant atmospheric humidity.
Overhead lines comprising bare conductors that are stretched between an appropriate pole system are well-known in the art. Said lines are generally used for the transmission of A.C. electrical energy having a high voltage (400-500kV).
Each conductor has a diameter of a few centimeters and can comprise a single tubular metallic body, or else, more fre-quently, several metallic wires grouped together.
Along the bare conductor, there is always manifested the so-called "corona effect" which is the ionization of the air in contact with the metallic surface under high voltage and which comprises a series of small electrical discharges. The "corona effect" is proportional to the field gradient existing around the conductor and hence, to the electrical tension applied. In the above-described conditions, the field gradient is around about 20kV/cm.
One of the consequences of the "corona effect" is the generation of noises. However, when the conductor is dry, noise generation is quite limited, and as for the disturbance effectively caused, it is practically negligible. On the contrary, when the conductor is wet, the noise is much more intense, and this is the source of significant disturbances which are irritating and annoying for passers-by and to those who are inhabitants of the immed~iate vicinity. Under these
2. ;~
~ :17~0~
conditions in fact, the conductibility of the air increases, and hence, there is had a more intense and effective ionisation.
The noise itself, is manifested as a continuous buzzing in the background, accompanied by frequent "peaks" of a higher intensity. The spectral analysis of the frequencies of this noise has permitted the verification of the high fre-quency (i.e. in the sonic and ultra-sonic ranges) and the low frequency components, corresponding to the network frequency (for example, 50 Hz) and also its harmonics. From this arises the probability of "beats", i.e. of positive or negative com-binations of the various acoustic waves, and hence, of in-creasing or decreasing the noise created.
The supression, or at least, a drastic reduction of this noise is even more urgently required, particularly when one considers the tendency to progressively increase the working voltage of the overhead lines.
The immediate solution, from the conceptual viewpoint, would appear to be to insulate the conductors themselves by covering them with a layer of insulating plastic material, for the purpose of eliminating the electrical contact between the metallic parts under high electrical tension and the air, and in this manner to supress the "corona effect". This solution, which would transform each conductor into a kind of an electric cable, presents, nevertheless, various drawbacks.
In the first place, in order to be able to effect-ively reduce to zero the gradient of the electrical field around the conductor, the insulating plastic cladding must have a rather consistent thickness and be covered with a semi conductive shield electrically connected to earth. This will involve, on one hand, a significant increase in the weight of the overhead conductor, and on the other hand, an ob~ious ~ 17430~
technical complication.
Besides this, the plastic material must also possess chemical and physical characteristics, such as to be resistant, with the passage of time, to the attacks of atmospheric agents, and this implies an elaborate formulation of the plastic material composition.
Moreover, there are obvious technical difficulties involved, for assuring that the insulating cladding or the semi-conductive shield does not become damaged or deteriorated, at the joining-points of the conductors to the insulators that are connected-up on the pole system of the overhead lines.
This could give rise to dangerous discharges that could prove destructive throughout the entire insulating cladding.
A second solution is respresented by the so-called "sand-blasting process" which consists of treating the surface of the conductors with a spray of abrasive sand. This "sand-blasting" gives rise to the formation of microscopic roughness and upwardly projecting bumps on the conductor surface, which effects are, to some extent, similar to those effects produced through the natural aging process of the metallic conductors which are exposed to the action of atmospheric agents. Tests, carried out on conductors that are treated in this way, have shown a certain reduction in the continuous components of the "background" noises, but on the other hand, an observable in-crease of the "peaks". Therefore, even this solution is not without its drawbacks.
One object of the present invention is to overcome the hereinbefore stated drawbacks while supressing, or at least drastically reducing, the noise that is generated along the wet conductor of an overhead line, such as during or after a rainfall, or under conditions of elevated atmospheric humidity, for example! fog-According to the present invention, therefore, there is provided a conductor unit for overhead lines for transmitting high voltage, alterna-ting, electric current, said unit comprising one or more electrical con-ductors surrounded by a thin, semi-conductive layer of a mixture of an insulating material, at least one conductive material and at least one hydrophilic material, said unit having the characteristic that during rain-fall or significant atmospheric humidity corona noise is suppressed or drastically reduced as compared to the same unit without a hydrophilic material in the semi-conductive layer.
The present invention will be better understood from the following description which should be considered in conjunction with the single Figure of the accompanying drawing and from the examples set forth in the Table set forth hereinafter.
It should be understood that said Figure and said Table of exam-ples, are merely representative, and are given only by way of indicating particular cases for the practical realization of the conductor unit, within the scope of the present invention, In Figure 1, there is a conductor unit 'C' comprising several metallic wires 10 grouped together and covered by thin plastic material cladding 11. Of course, in place of several metallic wires 10 grouped together, there can also be a single tubular metallic body.
The cladding of plastic material which is applied around said wires 10, or over said tubular body, has a very slight thickness. By way of reference, the cladding 11 may be a thin layer having a thickness that is in the range from 1 to 3 mm The Applicant has, in fact, surprisingly found that the noises associated with wet conductors that transmit high voltage, A.C. currents, can be suppressed, or at least, ~ 17430~
drastically reduced by means of covering the conductors them-selves, with a thin plastic cladding on the condition that the mixture which forms said plastic cladding is rendered semi-conductive through the addition of at least one conductive compound and that it is also rendered hydrophilic by the addition of at least one hydrophilic compound.
In the Table, there are given the compositions of some preferred examples of said mixtures. In particular, it can be observed, that all the mixtures comprise a plastic resin or resin-rubber base (P.V.C., polyethylene etc. nitrile rubber, ethylene rubber, vinyl-acetate rubber etc.), various additives (anti-oxidants, plasticizers, lubricants etc.) at least one conductive compound and at least one hydrophilic compound.
Said conductive compound, which generally will be a carbon-black, permits the electrical field around said plastic cladding to be equal, or nearly equal, to the electrical field around the bare conductor. The quantity, in parts by weight, of said conductive compound, or of a mixture of said conductive compounds, can very from 5 to 40 parts by weight, to 100 parts by weight of the mixture itself.
The hydrophilic compounds used in the examples given in the Table, are as follows:
Sorbitan-Monostearate (HLB = 4.7) Monoglycerides of Fatty Acids (HLB = 2.8)/Poly-oxyethyleneglycol-Laurate (HLB = 12.8) (Mixture 50/50, HLB = 5) Sorbitan Monolaurate (HLB = 8.6)/Phenolic Ether of Polyoxyethyleneglycol (HLB = 11) (Mixture 50/50, HLB = 10) Alkylphenyl-Polyoxyethyleneglycol (HLB = 11) Polyoxyethyleneglycol-Monolaurate (HLB = 14) Polyoxyethyleneglycol-Distearate (HLB = 16.4) Polyoxyethyleneglycol-Sorbitan-Monolaurate (HLB = 15) ~ 174307 Fatty Oxyethylized Alcohol (HLB = 17) Polyvinyl Alcohol For each compound, or for its mixture, in the Table there is indicated the value of the HLB (Hydrophile-~ipophile-Balance), a value which, as is knownl expresses a fundamental characteristic of a surfactant compound.
The quantity in parts by weight, of said hydrophilic compounds, when used alone, or mixed together, can vary from 1 to 10 parts by weight to 100 parts by weight of the mixture.
Said hydrophilic compound permits the water, which falls on the conductors as a result of rainfall, or as a result of the condensation of water vapour in the atmosphere, to be-come distributed, in a homogeneous manner, as a thin film over the entire conductor unit surface.
When a conductor unit is prepared according to the present invention, it can be verified that the noise, as com-pared to wet, unclad conductors, became supressed, or dras-tically reduced. The tests have been carried out in a so-called "anechoic chamber", an acoustically insulated chamber, wherein there are disposed conductor lengths kept under elec-trical tension and where it is possible to simulate the out-side atmospheric conditions. According to the known processes, it is possible to measure in said chamber the intensity of the noise and to survey the relative frequency spectrum.
Among the examples shown in the Eollowing Table, the best results were obtained by the mixtures corresponding to the examples No. 4 and 5.
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1 17~3~7 The advantages of the present invention can be attributed, by way of hypothesis, to the fact that the hydro-philic character of the plastic cladding material r forces the water to disperse in the form of a thin film, over the entire surface of the conductor, and hence, to be subjected to a rapid evaporation. Such evaporation is increased by the heat emanated by the conductor itself.
On the other hand, the semi-conductive character of the plastic material causes said cladding to remain un-stressed by any significant field gradient, and hence, it is not sub-jected to any rapid deterioration.
As has already been stated, even when the conductor is covered by insulation, there is always established a certain gradient between the conductor and the air, unless the insula-tion has a very great thickness and there is a further covering of a semi-conductive shield.
Although preferred embodiments of the present in-vention have been described and illustrated, it will be appa-rent to those skilled in the art that various modifications may be made without departing from the principles of the invention.
10 .
~ :17~0~
conditions in fact, the conductibility of the air increases, and hence, there is had a more intense and effective ionisation.
The noise itself, is manifested as a continuous buzzing in the background, accompanied by frequent "peaks" of a higher intensity. The spectral analysis of the frequencies of this noise has permitted the verification of the high fre-quency (i.e. in the sonic and ultra-sonic ranges) and the low frequency components, corresponding to the network frequency (for example, 50 Hz) and also its harmonics. From this arises the probability of "beats", i.e. of positive or negative com-binations of the various acoustic waves, and hence, of in-creasing or decreasing the noise created.
The supression, or at least, a drastic reduction of this noise is even more urgently required, particularly when one considers the tendency to progressively increase the working voltage of the overhead lines.
The immediate solution, from the conceptual viewpoint, would appear to be to insulate the conductors themselves by covering them with a layer of insulating plastic material, for the purpose of eliminating the electrical contact between the metallic parts under high electrical tension and the air, and in this manner to supress the "corona effect". This solution, which would transform each conductor into a kind of an electric cable, presents, nevertheless, various drawbacks.
In the first place, in order to be able to effect-ively reduce to zero the gradient of the electrical field around the conductor, the insulating plastic cladding must have a rather consistent thickness and be covered with a semi conductive shield electrically connected to earth. This will involve, on one hand, a significant increase in the weight of the overhead conductor, and on the other hand, an ob~ious ~ 17430~
technical complication.
Besides this, the plastic material must also possess chemical and physical characteristics, such as to be resistant, with the passage of time, to the attacks of atmospheric agents, and this implies an elaborate formulation of the plastic material composition.
Moreover, there are obvious technical difficulties involved, for assuring that the insulating cladding or the semi-conductive shield does not become damaged or deteriorated, at the joining-points of the conductors to the insulators that are connected-up on the pole system of the overhead lines.
This could give rise to dangerous discharges that could prove destructive throughout the entire insulating cladding.
A second solution is respresented by the so-called "sand-blasting process" which consists of treating the surface of the conductors with a spray of abrasive sand. This "sand-blasting" gives rise to the formation of microscopic roughness and upwardly projecting bumps on the conductor surface, which effects are, to some extent, similar to those effects produced through the natural aging process of the metallic conductors which are exposed to the action of atmospheric agents. Tests, carried out on conductors that are treated in this way, have shown a certain reduction in the continuous components of the "background" noises, but on the other hand, an observable in-crease of the "peaks". Therefore, even this solution is not without its drawbacks.
One object of the present invention is to overcome the hereinbefore stated drawbacks while supressing, or at least drastically reducing, the noise that is generated along the wet conductor of an overhead line, such as during or after a rainfall, or under conditions of elevated atmospheric humidity, for example! fog-According to the present invention, therefore, there is provided a conductor unit for overhead lines for transmitting high voltage, alterna-ting, electric current, said unit comprising one or more electrical con-ductors surrounded by a thin, semi-conductive layer of a mixture of an insulating material, at least one conductive material and at least one hydrophilic material, said unit having the characteristic that during rain-fall or significant atmospheric humidity corona noise is suppressed or drastically reduced as compared to the same unit without a hydrophilic material in the semi-conductive layer.
The present invention will be better understood from the following description which should be considered in conjunction with the single Figure of the accompanying drawing and from the examples set forth in the Table set forth hereinafter.
It should be understood that said Figure and said Table of exam-ples, are merely representative, and are given only by way of indicating particular cases for the practical realization of the conductor unit, within the scope of the present invention, In Figure 1, there is a conductor unit 'C' comprising several metallic wires 10 grouped together and covered by thin plastic material cladding 11. Of course, in place of several metallic wires 10 grouped together, there can also be a single tubular metallic body.
The cladding of plastic material which is applied around said wires 10, or over said tubular body, has a very slight thickness. By way of reference, the cladding 11 may be a thin layer having a thickness that is in the range from 1 to 3 mm The Applicant has, in fact, surprisingly found that the noises associated with wet conductors that transmit high voltage, A.C. currents, can be suppressed, or at least, ~ 17430~
drastically reduced by means of covering the conductors them-selves, with a thin plastic cladding on the condition that the mixture which forms said plastic cladding is rendered semi-conductive through the addition of at least one conductive compound and that it is also rendered hydrophilic by the addition of at least one hydrophilic compound.
In the Table, there are given the compositions of some preferred examples of said mixtures. In particular, it can be observed, that all the mixtures comprise a plastic resin or resin-rubber base (P.V.C., polyethylene etc. nitrile rubber, ethylene rubber, vinyl-acetate rubber etc.), various additives (anti-oxidants, plasticizers, lubricants etc.) at least one conductive compound and at least one hydrophilic compound.
Said conductive compound, which generally will be a carbon-black, permits the electrical field around said plastic cladding to be equal, or nearly equal, to the electrical field around the bare conductor. The quantity, in parts by weight, of said conductive compound, or of a mixture of said conductive compounds, can very from 5 to 40 parts by weight, to 100 parts by weight of the mixture itself.
The hydrophilic compounds used in the examples given in the Table, are as follows:
Sorbitan-Monostearate (HLB = 4.7) Monoglycerides of Fatty Acids (HLB = 2.8)/Poly-oxyethyleneglycol-Laurate (HLB = 12.8) (Mixture 50/50, HLB = 5) Sorbitan Monolaurate (HLB = 8.6)/Phenolic Ether of Polyoxyethyleneglycol (HLB = 11) (Mixture 50/50, HLB = 10) Alkylphenyl-Polyoxyethyleneglycol (HLB = 11) Polyoxyethyleneglycol-Monolaurate (HLB = 14) Polyoxyethyleneglycol-Distearate (HLB = 16.4) Polyoxyethyleneglycol-Sorbitan-Monolaurate (HLB = 15) ~ 174307 Fatty Oxyethylized Alcohol (HLB = 17) Polyvinyl Alcohol For each compound, or for its mixture, in the Table there is indicated the value of the HLB (Hydrophile-~ipophile-Balance), a value which, as is knownl expresses a fundamental characteristic of a surfactant compound.
The quantity in parts by weight, of said hydrophilic compounds, when used alone, or mixed together, can vary from 1 to 10 parts by weight to 100 parts by weight of the mixture.
Said hydrophilic compound permits the water, which falls on the conductors as a result of rainfall, or as a result of the condensation of water vapour in the atmosphere, to be-come distributed, in a homogeneous manner, as a thin film over the entire conductor unit surface.
When a conductor unit is prepared according to the present invention, it can be verified that the noise, as com-pared to wet, unclad conductors, became supressed, or dras-tically reduced. The tests have been carried out in a so-called "anechoic chamber", an acoustically insulated chamber, wherein there are disposed conductor lengths kept under elec-trical tension and where it is possible to simulate the out-side atmospheric conditions. According to the known processes, it is possible to measure in said chamber the intensity of the noise and to survey the relative frequency spectrum.
Among the examples shown in the Eollowing Table, the best results were obtained by the mixtures corresponding to the examples No. 4 and 5.
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i~ O ~ ~ oo 11 ~ O 11 ~ 11 11 X ~1 ~¢ ~
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z m H U~ .) O H i~ l 11 ill m z m a ~ C H Ul ~ 3 ~m z ~ ~ ~ 3 z H-- m m Z ~ Z ~ Z H
~ i~l H ~ H m o o H ~ 11 ~ o H Z O ~ ~1 0 ~ ~ H al m o m O ~ ~ iH ~ H~ m ~ ~ ~ ~ ~
9- ~7~1307 ~ ~ 11 1111 o 11 11 11 11 11 a~ 11 11 11 11 CO 11 11 ,, ~ 11 t.q ~ H
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o U~
E~ ~ ~; ~ 11 ~ 11 11 11 X ~ c ~ P~
H E~ a Z ~ u~ ~r 11 11 11 11 Z ~
H rl ~r llll ll ll ll a a c~
_ ~ 11 1111 11 11 ~ 11 1111 11 11 o ~ 11 11 11 11 11 .
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1 17~3~7 The advantages of the present invention can be attributed, by way of hypothesis, to the fact that the hydro-philic character of the plastic cladding material r forces the water to disperse in the form of a thin film, over the entire surface of the conductor, and hence, to be subjected to a rapid evaporation. Such evaporation is increased by the heat emanated by the conductor itself.
On the other hand, the semi-conductive character of the plastic material causes said cladding to remain un-stressed by any significant field gradient, and hence, it is not sub-jected to any rapid deterioration.
As has already been stated, even when the conductor is covered by insulation, there is always established a certain gradient between the conductor and the air, unless the insula-tion has a very great thickness and there is a further covering of a semi-conductive shield.
Although preferred embodiments of the present in-vention have been described and illustrated, it will be appa-rent to those skilled in the art that various modifications may be made without departing from the principles of the invention.
10 .
Claims (15)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A conductor unit for overhead lines for trans-mitting high voltage, alternating, electric current, said unit comprising one or more electrical conductors surrounded by a thin, semi-conductive layer of a mixture of an insulating material, at least one conductive material and at least one hydrophilic material, said unit having the characteristic that during rainfall or significant atmospheric humidity corona noise is suppressed or drastically reduced as compared to the same unit without a hydrophilic material in the semi-conductive layer.
2. A conductor unit as set forth in claim 1 wherein said conductive material is carbon black.
3. A conductor unit as set forth in claim 1 or 2 wherein the conductive material is present in an amount from 5 to 40 parts by weight of the total weight of the mixture.
4. A conductor unit as set forth in claim 1 wherein the hydrophilic material is present in an amount from 1 to 10 parts by weight of the total weight of the mixture.
5. A conductor unit as set forth in claim 1 wherein the conductive material is present in an amount of 5 to 40 parts by weight of the total weight of the mixture and the hydrophilic material is present in an amount from 1 to 10 parts by weight of the total weight of the mixture.
6. A conductor unit as set forth in claim 1 or 5 where-in the thickness of the semi-conductive layer is in the range from 1 to 3 millimeters.
7. A conductor unit as set forth in claim 1 or 5 where-in said hydrophilic material is sorbitan-monostearate having an HLB of 4.7.
8. A conductor unit as set forth in claim 1 or 5 wherein said hydrophilic material is a mixture of 50/50 parts by weight of monoglyeerides of fatty acids having an HLB of 2.8 and of polyoxyethyleneglycol laurate having an HLB of 12.8 and the mixture has an HLB of 5.
9. A conductor unit as set forth in claim 1 or 5 wherein said hydrophilic material is a mixture of 50/50 parts by weight of sorbitan monolaurate having an HLB of 8.6, and of a phenolic ether of polyoxyethyleneglyeol having an HLB of 11 and the mixture has an HLB of 10.
10. A conductor unit as set forth in claim 1 or 5 wherein said hydrophilic material is alkyl-phenyl polyoxyethyl-eneglycol having an HLB of 11.
11. A conductor unit as set forth in claim 1 or 5 wherein said hydrophilic material is polyoxyethyleneglycol-monolaurate having an HLB of 14.
12. A eonduetor unit as set forth in elaim 1 or 5 wherein said hydrophilie material is polyoxyethyleneglyeol-di-stearate having an HLB of 16.4.
13. A eonductor unit as set forth in claim 1 or 5 wherein said hydrophilic material is polyoxyethyleneglycol-sorbitan-monolaurate having an HLB of 15.
14. A eonductor unit as set forth in claim 1 or 5 wherein said hydrophilic material is fatty oxyethylized alcohol having an HLB of 17.
15. A conductor unit as set forth in claim 1 or 5 wherein said hydrophilic material is a polyvinylic alcohol.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IT83634A/80 | 1980-06-30 | ||
| IT83634/80A IT1136539B (en) | 1980-06-30 | 1980-06-30 | PERFECTED AERIAL LINE CONDUCTOR |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1174307A true CA1174307A (en) | 1984-09-11 |
Family
ID=11323451
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000380865A Expired CA1174307A (en) | 1980-06-30 | 1981-06-29 | Above-ground conductor unit with corona noise reduction covering |
Country Status (13)
| Country | Link |
|---|---|
| JP (1) | JPS5715308A (en) |
| AR (1) | AR225084A1 (en) |
| AU (1) | AU542216B2 (en) |
| BR (1) | BR8104092A (en) |
| CA (1) | CA1174307A (en) |
| DE (1) | DE3125509A1 (en) |
| DK (1) | DK147777C (en) |
| ES (1) | ES503967A0 (en) |
| FR (1) | FR2485792A1 (en) |
| GB (1) | GB2079521B (en) |
| IT (1) | IT1136539B (en) |
| NZ (1) | NZ197412A (en) |
| SE (1) | SE8103935L (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE512745C2 (en) * | 1998-08-06 | 2000-05-08 | Abb Ab | Electric DC cable with insulation system comprising an extruded polyethylene composition and a method for producing such cable |
| FR2874283B1 (en) * | 2004-08-12 | 2006-12-15 | Electricite De France | REDUCTION OF AERIAL LINE NOISE BY TEXTILE COATING |
| FR2874282B1 (en) | 2004-08-12 | 2006-10-27 | Electricite De France | REDUCTION OF THE NOISE OF AERIAL LINES BY PLASTIC SHEATH |
| FR2990047B1 (en) * | 2012-04-27 | 2015-02-20 | Nexans | HIGH VOLTAGE ELECTRICAL TRANSMISSION CABLE |
| US9859038B2 (en) | 2012-08-10 | 2018-01-02 | General Cable Technologies Corporation | Surface modified overhead conductor |
| US10957468B2 (en) | 2013-02-26 | 2021-03-23 | General Cable Technologies Corporation | Coated overhead conductors and methods |
| WO2017015512A1 (en) | 2015-07-21 | 2017-01-26 | General Cable Technologies Corporation | Electrical accessories for power transmission systems and methods for preparing such electrical accessories |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1465846A1 (en) * | 1963-06-25 | 1969-03-27 | Licentia Gmbh | High-voltage overhead line cable with high electrical strength |
-
1980
- 1980-06-30 IT IT83634/80A patent/IT1136539B/en active
-
1981
- 1981-04-24 JP JP6231281A patent/JPS5715308A/en active Pending
- 1981-06-09 AU AU71428/81A patent/AU542216B2/en not_active Ceased
- 1981-06-15 NZ NZ197412A patent/NZ197412A/en unknown
- 1981-06-15 AR AR285710A patent/AR225084A1/en active
- 1981-06-23 SE SE8103935A patent/SE8103935L/en not_active Application Discontinuation
- 1981-06-25 DK DK280981A patent/DK147777C/en active
- 1981-06-26 GB GB8119843A patent/GB2079521B/en not_active Expired
- 1981-06-29 BR BR8104092A patent/BR8104092A/en unknown
- 1981-06-29 CA CA000380865A patent/CA1174307A/en not_active Expired
- 1981-06-29 FR FR8112730A patent/FR2485792A1/en active Granted
- 1981-06-29 DE DE19813125509 patent/DE3125509A1/en not_active Withdrawn
- 1981-06-30 ES ES503967A patent/ES503967A0/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| DK147777B (en) | 1984-12-03 |
| ES8204556A1 (en) | 1982-05-01 |
| SE8103935L (en) | 1981-12-31 |
| DE3125509A1 (en) | 1982-05-13 |
| GB2079521B (en) | 1984-04-18 |
| FR2485792B1 (en) | 1984-04-20 |
| AU7142881A (en) | 1982-01-07 |
| IT1136539B (en) | 1986-08-27 |
| JPS5715308A (en) | 1982-01-26 |
| GB2079521A (en) | 1982-01-20 |
| NZ197412A (en) | 1983-07-15 |
| BR8104092A (en) | 1982-03-16 |
| AR225084A1 (en) | 1982-02-15 |
| FR2485792A1 (en) | 1981-12-31 |
| AU542216B2 (en) | 1985-02-14 |
| ES503967A0 (en) | 1982-05-01 |
| DK280981A (en) | 1981-12-31 |
| IT8083634A0 (en) | 1980-06-30 |
| DK147777C (en) | 1985-05-20 |
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