WO2021063477A1 - High voltage transformer and method to isolate parts of the voltage transformer - Google Patents

High voltage transformer and method to isolate parts of the voltage transformer Download PDF

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Publication number
WO2021063477A1
WO2021063477A1 PCT/EP2019/076438 EP2019076438W WO2021063477A1 WO 2021063477 A1 WO2021063477 A1 WO 2021063477A1 EP 2019076438 W EP2019076438 W EP 2019076438W WO 2021063477 A1 WO2021063477 A1 WO 2021063477A1
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WO
WIPO (PCT)
Prior art keywords
voltage transformer
particles
housing
electric wire
coil arrangement
Prior art date
Application number
PCT/EP2019/076438
Other languages
French (fr)
Inventor
Fabrizio Negri
Dario SANTINELLI
Original Assignee
Siemens Energy Global GmbH & Co. KG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Siemens Energy Global GmbH & Co. KG filed Critical Siemens Energy Global GmbH & Co. KG
Priority to PCT/EP2019/076438 priority Critical patent/WO2021063477A1/en
Publication of WO2021063477A1 publication Critical patent/WO2021063477A1/en

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F38/00—Adaptations of transformers or inductances for specific applications or functions
    • H01F38/20—Instruments transformers
    • H01F38/22—Instruments transformers for single phase ac
    • H01F38/24—Voltage transformers
    • H01F38/26—Constructions
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/02—Casings
    • H01F27/022—Encapsulation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/08—Cooling; Ventilating
    • H01F27/10—Liquid cooling
    • H01F27/12—Oil cooling
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/28—Coils; Windings; Conductive connections
    • H01F27/32—Insulating of coils, windings, or parts thereof
    • H01F27/323—Insulation between winding turns, between winding layers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/28—Coils; Windings; Conductive connections
    • H01F27/32—Insulating of coils, windings, or parts thereof
    • H01F27/324—Insulation between coil and core, between different winding sections, around the coil; Other insulation structures
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/28—Coils; Windings; Conductive connections
    • H01F27/32—Insulating of coils, windings, or parts thereof
    • H01F27/327—Encapsulating or impregnating
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/04—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing coils
    • H01F41/12—Insulating of windings
    • H01F41/122—Insulating between turns or between winding layers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/04—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing coils
    • H01F41/12—Insulating of windings
    • H01F41/125—Other insulating structures; Insulating between coil and core, between different winding sections, around the coil
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/04—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing coils
    • H01F41/12—Insulating of windings
    • H01F41/127—Encapsulating or impregnating

Definitions

  • the present invention relates to a voltage transformer for high voltages and a method for the voltage transformer, comprising a housing and at least a coil arrangement, with an alternating stack of wounded electric wire layers and wrapped paper electrically insulating adjacent electric wire layers, with an isolation material reinforcing the electrical isolation within the housing.
  • Oil insulated voltage transformers are for example known from DE 2115113 B2.
  • the inductive voltage transformers are used to transform respectively measure high alternating voltages, i.e. AC voltages, particularly voltages in the range of 72 to 550 kV.
  • An inductive high voltage transformer comprises a housing and a coil arrangement, which is designed to transform a high voltage to measure the voltage in form of a particularly proportional low voltage.
  • the working principle of inductive high voltage transformers respectively instrument transformers is analogous transformers, with measurement devices at low voltage side.
  • windings are arranged around a magnetic core, for example with a magnetic core in U shape, forming at least two electrically isolated coils. Voltage changes in one coil induce voltage changes in the other coil.
  • Different dimensions and/or numbers of windings of the two coils enable a transformation of high voltage to low voltage, which can be measured with low voltage measuring devices as are for example voltmeters.
  • a measured voltage change at low voltage side respectively coil which is called secondary coil, is particularly proportional to a voltage change at high voltage side respectively coil, which is called primary coil.
  • paper tape is used, particularly soaked with isolator fluid, for example transformer oil.
  • Windings of coils are produced by winding for example an electric wire around a core, for example a copper wire around a tube particularly made of electrically isolating plastics and/or electrically isolating composite material, and taping particularly each layer of wires with for example oil-soaked paper tape.
  • the coil arrangement respectively outer shell of the coil arrangement is wrapped with paper tape and/or sheets, i.e. paper sleeves, particularly soaked with isolator fluid, for example transformer oil.
  • a wrapping process comprises to manually provide paper sheets or tape, mount it within the core particularly tube projecting on both sides outside the core particularly tube, cutting slices off projecting paper, and wrapping paper slices around the coil assembly, to enwrap and electrically isolate the coil assembling particularly completely.
  • a manual wrapping procedure with steps like cutting slices off paper takes much time, particularly days, is expensive due to manpower costs and suffers from human errors. Due to complex shapes of coil arrangements and difficult cutting and wrapping steps, an automation of wrapping processes is not possible or at least difficult and expensive.
  • An object of the present invention is to overcome the problems described above. Especially an object of the present invention is to describe a method to insulate parts of a voltage transformer for high voltages and the voltage transformer with electrically insulated parts, with an easy to produce and cost-effective insulation, particularly at high voltages, particularly higher than 72 kV, which can be automated.
  • the above objects are achieved by a voltage transformer for high voltages according to claim 1 and/or by a method for a voltage transformer, particularly for a voltage transformer described above, according to claim 12.
  • a voltage transformer for high voltages comprises a housing and at least a coil arrangement, with an alternating stack of wounded electric wire layers and wrapped paper electrically insulating adjacent electric wire layers, with an isolation material reinforcing the electrical isolation within the housing.
  • the isolation material comprises particles in form of powder and/or paste.
  • Particles especially in form of powder and/or paste, are easy to handle, particularly easy to fill in a housing for example by a machine.
  • isolation material comprising particles enables an automation of production, saves costs and is easy to perform, with no or little fault probability.
  • the human contribution during a manufacturing process can be reduced, introducing automated respectively fully automated processes, leading to cost, time and fault reductions.
  • the particles can be impregnated by an insulating fluid and/or embedded in fluid, particularly liquid and/or gas.
  • the insulating fluid can be or can comprise oil, particularly mineral oil and/or a synthetic oil, and/or ester, particularly vegetable esters. These materials are good isolation materials, especially at high voltages up to 550 kV. Time for impregnation of isolation material can be reduced, using particles filled into the housing of the voltage transformer and impregnation of particles by insulation fluid, before and/or after filling.
  • Particles can be composed of or can comprise paper material, and/or cellulose, and/or silicon. Paper material and/or cellulose are good isolation materials, especially at high voltages up to 550 kV, are environmentally friendly, cost- effective and easy to handle as particles. Particles of paper material, silicon and/or cellulose can be easy handled fully automated and are easy to produce in specific sizes.
  • Particle size can be in the range of micro- and/or nano meter, and/or the isolation material can comprise particles with a size in the range of micro- and/or nano-meter. This size gives a high fill factor, with little amount of space between particles, can easy be produced of paper material, silicon and/or cellulose, can be easy impregnated by a fluid, and/or is easy to fill into a housing, particularly fully automated.
  • the particles can be arranged within the alternating stack of wounded electric wire layers and wrapped paper electrically insulating adjacent electric wire layers, particularly in- between wires of a layer and/or in-between wrapped paper.
  • the particles can be arranged within the housing, filling free space between housing and coil arrangement. Thereby a good electrical isolation of the coil arrangement towards particularly the housing is reached, particularly at high voltages higher than 72 kV, rendering a wrapping process of the coil arrangement unnecessary and enabling an automated process, with advantages as described before.
  • the particles can be in spherical form, and/or particles can be in fibrous form. Both forms enable a high surface to volume ratio with advantages as described before.
  • the surface to volume ratio of particles can be higher, particularly at least two times, particularly at least ten times higher than for the same material in form of sheets.
  • a high surface to volume ratio of particles enables a high electrical isolation effect, a good dissolution in fluids and/or impregnation in for example fluids.
  • the fill factor of particles in the isolation material can be high, particularly maximized, for example by filling and pressing particles particularly in powder form into the housing and/or ramming the particles in the housing to get a high fill factor.
  • a high fill factor of particles enables a high electrical strength, i.e. a high electrical isolation effect. Particles act in difference to the state of the art not as contaminants, reducing electrical withstand capabilities, but particles particularly with high fill factor increase electrical withstand capabilities, particularly isolation between parts of the voltage transformer.
  • the voltage transformer can be used at voltages above 72 kV, particularly in the range of 123 kV to 300 kV and/or of 362 kV to 550 kV. With state of the art isolation, without wrapping the coil assembling, these high voltages above 72 kV are not possible without electric faults, particularly without increasing the size of the housing. An increase in dimensions of the housing include high costs and a high consume of space in use.
  • the at least one coil arrangement with an alternating stack of wounded electric wire layers and wrapped paper electrically insulating adjacent electric wire layers, can be in form of a circular cylinder, with openings between wrapped paper layers towards circular base and/or cover side of the cylinder.
  • Such circular cylinders are easy and cost effective to produce, particularly in automated processes and/or with little time consumption.
  • Particles as isolation material and/or isolation fluids like oil are able to ingress easily in openings between wrapped paper layers, closing openings and/or electrically isolating openings respectively coils towards for example the housing of the voltage transformer, rendering a wrapping of the coil assembly with paper unnecessary, with advantages as described before.
  • the openings can be filled with isolation material comprising particles in form of powder and/or paste, particularly completely electrically isolating filled by powder and/or paste.
  • isolation material comprising particles in form of powder and/or paste, particularly completely electrically isolating filled by powder and/or paste.
  • a complete isolating enables the use at high voltages in relatively small housings of the voltage transformer compared to the state of the art.
  • Particles in form of powder and/or paste are easy to handle, particularly easy to fill in a housing for example by a machine, enabling an automation of production, saving costs and ease the performing of production process, with no or little fault probability.
  • a method according to the present invention for a voltage transformer comprises that at least a coil arrangement, with an alternating stack of wounded electric wire layers and wrapped paper electrically insulating adjacent electric wire layers, is reinforced in electrical isolation properties by isolation material comprising particles in form of powder and/or paste.
  • the particles can get impregnated in the voltage transformer, particularly in the housing of the voltage transformer, after filling in the particles into the housing.
  • Particles can get impregnated to create a pulp, particularly after degassing, and afterwards the pulp can be filled into the voltage transformer housing.
  • a voltage above 72 kV applied to the voltage transformer can be transformed by the at least one coil arrangement, reinforced with electrically isolating particles in form of powder and/or paste, particularly with oil impregnated particles composed of or comprising paper material, and/or cellulose, and/or silicon.
  • FIG. 2 illustrates in section view the coil arrangement 8 of FIG. 1 according to the state of the art, with a stack 10 of layers of taped paper and wounded electric wires, wrapped by a paper sleeve 11, and
  • FIG. 3 illustrates in section view the coil arrangement 8 of FIG. 1 according to the present invention, with a stack 10 without wrapped paper sleeve 11, reinforced by isolation material comprising particles.
  • FIG. 1 is in section view a voltage transformer 1 for high voltages shown.
  • the voltage transformer 1 comprises a housing 2 and at least one coil arrangement 8, which is electrically insulated by an isolation material.
  • the housing 2 comprises an isolator 3, for example in form of a hollow cylindrical body respectively tube, with a base plate 4 and a cover plate 5, for example in form of cylindrical metal plates air tight closing the interior of isolator 3, arranged on a pedestal, for example three or four pillars made of metals like steel and/or aluminum, and with a terminal box 7 arranged next to one side of the isolator 3, particularly for devices to control, measure, process, store and send values and/or data of the voltage transformer 1, particularly the coil arrangement 8.
  • Coil arrangement 8 is for example connected to ground via pedestal 6 and base plate 4, and connected to a high voltage, particularly to be transformed and/or measured, via electrical connections, particularly through cover plate 5 and a high voltage terminal at the cover plate 5.
  • the high voltage terminal is designed to electrically connect the voltage transformer 1 respectively coil arrangement 8 with high voltage lines, electrical generators and/or electrical consumers, to transform and/or measure voltages of high voltage lines and/or devices.
  • Coil arrangement 8 is for example arranged at a U-shaped magnet core, particularly comprising layered iron and/or steel sheets.
  • a particularly air tide tube arranged between for example base plate 4 and terminal box 7, with electrical and/or optical wires connects devices to control, measure, process, store and send values and/or data of the voltage transformer 1 in terminal box 7 with the coil arrangement 8 and/or devices inside the housing 2 respectively the isolator 3 as for example sensors.
  • Isolator 3 comprises or consists of electric isolating material, particularly ceramic, silicone and/or composite materials, and is for example designed in form of a cylindrical hollow tube with circumferential plate fins at the outer surface of the isolator 3, to increase leakage current length at the isolator 3 outer surface.
  • Isolation material for example an insulating fluid, particularly gas and/or liquid, for example consisting of or comprising oil, particularly mineral oil and/or a synthetic oil, and/or ester, particularly vegetable esters, filled in the housing 2, is electrically isolating parts of the voltage transformer 1 like coil arrangement 8 from the housing 2.
  • housing 2 is built compact, with low spatial dimensions.
  • coil arrangement 8 exhibits a design according to FIG. 2.
  • the coil arrangement 8 comprises an alternating stack 10 of wounded electric wire layers and wrapped respectively taped paper electrically insulating adjacent electric wire layers, for example spooled on a core roll respectively wrapped/wind/taped on a cylindrical tube of nonmagnetic, electrically nonconductive material.
  • the production process comprises providing for example a cylindrical tube/core of nonmagnetic, electrically nonconductive material, for example plastic, ceramic, wood, and/or a composite material, rotating the tube/core around a longitudinal axis and winding/spooling a wire, for example a copper wire, as coil, layer by layer or at least as a layer around the tube/core alternating with a paper tape, which is wrapped/spooled/taped layer by layer or at least as a layer around particular layers of wire.
  • a wire for example a copper wire, as coil, layer by layer or at least as a layer around the tube/core alternating with a paper tape, which is wrapped/spooled/taped layer by layer or at least as a layer around particular layers of wire.
  • Different coils can be produced on one tube by winding/spooling several wires, particularly at least two wires, spatial and electrically separated in one layer and/or separated by isolator material, particularly at least one or more layers of paper, layer by layer with one wire in a respective layer and another, spatial and electrically separated wire in another layer.
  • Tube 9 can be part of coil arrangement 8 or can be removed at the end of the spooling process. In the embodiment of FIG. 2 tube 9 stays part of the coil arrangement 8, mechanically stabilizing and carrying the stack 10, and is not removed.
  • paper can be impregnated with oil, for example transformer oil.
  • the coil arrangement 8 respectively outer shell of the coil arrangement 8 is wrapped with several layers of paper tape and/or sheets for example in form of a sleeve 11, particularly soaked with isolator fluid, for example transformer oil.
  • Isolation material comprising particles in form of powder and/or paste is provided to the coil arrangement 8 during production, for example during winding/spooling a wire, for example a copper wire, as coil layer by layer or at least as a layer around the tube/core alternating with a paper tape, which is wrapped/spooled/taped layer by layer or at least as a layer around particular layers of wire.
  • Particles are for example deposited during production in a bath with particles, and/or by spraying particles during wrapping/spooling/taping.
  • Particles are filled into the housing for example through a particle filler inlet, not shown in FIG. 1, and or before closing the housing by cover plate 5.
  • the filling process can be fully automated, saving time and costs.
  • An impregnation of particles particularly by oil can be done before filling particles into the housing 2, producing a solution and/or slurry of particle material like paper material, and/or cellulose, and/or silicon in for example oil.
  • An impregnation of particles can alternatively or additionally be done after filling particles into the housing 2. With time a solution and/or slurry can coagulate, consolidate and/or solidify, or stay fluidic, particularly forming a paste.
  • the isolation material made of, respectively comprising particles, particularly impregnated by oil results in a good electrical isolation of particularly the coil arrangement 8 towards the housing 2 of the voltage transformer 1, particularly at voltages higher than 72 kV.
  • the voltage transformer 1 is useable/suitable for voltages above 72 kV, particularly in the range of 123 kV to 300 kV and/or of 362 kV to 550 kV, with a compact housing 2 and without electric faults and/or arcs at these high voltages.
  • the voltage transformer 1 can be an inductive voltage transformer and/or a power voltage transformer.
  • Particles of isolation material comprise paper material, and/or cellulose, and/or silicon or combinations of these materials.
  • Alternative isolator materials in form of particles can be used too, particularly oil solvable materials like plastics and/or porous materials like zeolite, and/or materials like silicon oxide.
  • Particles can be for example of spherical form, porous and/or fibrous.
  • An impregnation of particles for example with oil can be done before filling the particles into the voltage transformer 1 or after filling the particles into the voltage transformer 1.

Abstract

The present invention relates to a voltage transformer (1) for high voltages and a method for the voltage transformer (1), comprising a housing (2) and at least a coil arrangement (8), with an alternating stack of wounded electric wire layers and wrapped paper electrically insulating adjacent electric wire layers, with an isolation material reinforcing the electrical isolation within the housing (2). The isolation material comprises particles in form of powder and/or paste.

Description

Description
HIGH VOLTAGE TRANSFORMER AND METHOD TO ISOLATE PARTS OF THE VOLTAGE
TRANSFORMER
The present invention relates to a voltage transformer for high voltages and a method for the voltage transformer, comprising a housing and at least a coil arrangement, with an alternating stack of wounded electric wire layers and wrapped paper electrically insulating adjacent electric wire layers, with an isolation material reinforcing the electrical isolation within the housing.
Oil insulated voltage transformers are for example known from DE 2115113 B2. The inductive voltage transformers are used to transform respectively measure high alternating voltages, i.e. AC voltages, particularly voltages in the range of 72 to 550 kV. An inductive high voltage transformer comprises a housing and a coil arrangement, which is designed to transform a high voltage to measure the voltage in form of a particularly proportional low voltage. The working principle of inductive high voltage transformers respectively instrument transformers is analogous transformers, with measurement devices at low voltage side. For example, windings are arranged around a magnetic core, for example with a magnetic core in U shape, forming at least two electrically isolated coils. Voltage changes in one coil induce voltage changes in the other coil.
Different dimensions and/or numbers of windings of the two coils enable a transformation of high voltage to low voltage, which can be measured with low voltage measuring devices as are for example voltmeters. A measured voltage change at low voltage side respectively coil, which is called secondary coil, is particularly proportional to a voltage change at high voltage side respectively coil, which is called primary coil. To electrically isolate respectively separate windings and/or coils from each other, paper tape is used, particularly soaked with isolator fluid, for example transformer oil.
Windings of coils are produced by winding for example an electric wire around a core, for example a copper wire around a tube particularly made of electrically isolating plastics and/or electrically isolating composite material, and taping particularly each layer of wires with for example oil-soaked paper tape. In high voltage applications, to electrically isolate coils from each other and from the housing of the voltage transformer, the coil arrangement respectively outer shell of the coil arrangement is wrapped with paper tape and/or sheets, i.e. paper sleeves, particularly soaked with isolator fluid, for example transformer oil.
A wrapping process comprises to manually provide paper sheets or tape, mount it within the core particularly tube projecting on both sides outside the core particularly tube, cutting slices off projecting paper, and wrapping paper slices around the coil assembly, to enwrap and electrically isolate the coil assembling particularly completely. A manual wrapping procedure with steps like cutting slices off paper takes much time, particularly days, is expensive due to manpower costs and suffers from human errors. Due to complex shapes of coil arrangements and difficult cutting and wrapping steps, an automation of wrapping processes is not possible or at least difficult and expensive.
An object of the present invention is to overcome the problems described above. Especially an object of the present invention is to describe a method to insulate parts of a voltage transformer for high voltages and the voltage transformer with electrically insulated parts, with an easy to produce and cost-effective insulation, particularly at high voltages, particularly higher than 72 kV, which can be automated. The above objects are achieved by a voltage transformer for high voltages according to claim 1 and/or by a method for a voltage transformer, particularly for a voltage transformer described above, according to claim 12.
A voltage transformer for high voltages according to the present invention comprises a housing and at least a coil arrangement, with an alternating stack of wounded electric wire layers and wrapped paper electrically insulating adjacent electric wire layers, with an isolation material reinforcing the electrical isolation within the housing. The isolation material comprises particles in form of powder and/or paste.
Particles, especially in form of powder and/or paste, are easy to handle, particularly easy to fill in a housing for example by a machine. The use of isolation material comprising particles enables an automation of production, saves costs and is easy to perform, with no or little fault probability. There is no manual wrapping procedure needed to isolate the coil arrangement, where steps like wrapping and cutting paper into slices cannot be fully automated, is costly, time consuming and not easy to perform. The human contribution during a manufacturing process can be reduced, introducing automated respectively fully automated processes, leading to cost, time and fault reductions.
The particles can be impregnated by an insulating fluid and/or embedded in fluid, particularly liquid and/or gas. The insulating fluid can be or can comprise oil, particularly mineral oil and/or a synthetic oil, and/or ester, particularly vegetable esters. These materials are good isolation materials, especially at high voltages up to 550 kV. Time for impregnation of isolation material can be reduced, using particles filled into the housing of the voltage transformer and impregnation of particles by insulation fluid, before and/or after filling. Particles can be composed of or can comprise paper material, and/or cellulose, and/or silicon. Paper material and/or cellulose are good isolation materials, especially at high voltages up to 550 kV, are environmentally friendly, cost- effective and easy to handle as particles. Particles of paper material, silicon and/or cellulose can be easy handled fully automated and are easy to produce in specific sizes.
Particle size can be in the range of micro- and/or nano meter, and/or the isolation material can comprise particles with a size in the range of micro- and/or nano-meter. This size gives a high fill factor, with little amount of space between particles, can easy be produced of paper material, silicon and/or cellulose, can be easy impregnated by a fluid, and/or is easy to fill into a housing, particularly fully automated.
The particles can be arranged within the alternating stack of wounded electric wire layers and wrapped paper electrically insulating adjacent electric wire layers, particularly in- between wires of a layer and/or in-between wrapped paper. Thereby a good electrical isolation of adjacent windings, different coils and/or the coil arrangement towards particularly the housing is reached, particularly at high voltages higher than 72 kV, rendering a wrapping process of the coil arrangement unnecessary, with steps like cutting paper, and enabling an automated process.
The particles can be arranged within the housing, filling free space between housing and coil arrangement. Thereby a good electrical isolation of the coil arrangement towards particularly the housing is reached, particularly at high voltages higher than 72 kV, rendering a wrapping process of the coil arrangement unnecessary and enabling an automated process, with advantages as described before.
The particles can be in spherical form, and/or particles can be in fibrous form. Both forms enable a high surface to volume ratio with advantages as described before. The surface to volume ratio of particles can be higher, particularly at least two times, particularly at least ten times higher than for the same material in form of sheets. A high surface to volume ratio of particles enables a high electrical isolation effect, a good dissolution in fluids and/or impregnation in for example fluids.
The fill factor of particles in the isolation material can be high, particularly maximized, for example by filling and pressing particles particularly in powder form into the housing and/or ramming the particles in the housing to get a high fill factor. A high fill factor of particles enables a high electrical strength, i.e. a high electrical isolation effect. Particles act in difference to the state of the art not as contaminants, reducing electrical withstand capabilities, but particles particularly with high fill factor increase electrical withstand capabilities, particularly isolation between parts of the voltage transformer.
The voltage transformer can be used at voltages above 72 kV, particularly in the range of 123 kV to 300 kV and/or of 362 kV to 550 kV. With state of the art isolation, without wrapping the coil assembling, these high voltages above 72 kV are not possible without electric faults, particularly without increasing the size of the housing. An increase in dimensions of the housing include high costs and a high consume of space in use.
The at least one coil arrangement, with an alternating stack of wounded electric wire layers and wrapped paper electrically insulating adjacent electric wire layers, can be in form of a circular cylinder, with openings between wrapped paper layers towards circular base and/or cover side of the cylinder. Such circular cylinders are easy and cost effective to produce, particularly in automated processes and/or with little time consumption. Particles as isolation material and/or isolation fluids like oil are able to ingress easily in openings between wrapped paper layers, closing openings and/or electrically isolating openings respectively coils towards for example the housing of the voltage transformer, rendering a wrapping of the coil assembly with paper unnecessary, with advantages as described before. The openings can be filled with isolation material comprising particles in form of powder and/or paste, particularly completely electrically isolating filled by powder and/or paste. A complete isolating enables the use at high voltages in relatively small housings of the voltage transformer compared to the state of the art. Particles in form of powder and/or paste are easy to handle, particularly easy to fill in a housing for example by a machine, enabling an automation of production, saving costs and ease the performing of production process, with no or little fault probability.
A method according to the present invention for a voltage transformer, particularly for a voltage transformer as described before, comprises that at least a coil arrangement, with an alternating stack of wounded electric wire layers and wrapped paper electrically insulating adjacent electric wire layers, is reinforced in electrical isolation properties by isolation material comprising particles in form of powder and/or paste.
The particles can get impregnated in the voltage transformer, particularly in the housing of the voltage transformer, after filling in the particles into the housing.
Particles can get impregnated to create a pulp, particularly after degassing, and afterwards the pulp can be filled into the voltage transformer housing.
A voltage above 72 kV applied to the voltage transformer can be transformed by the at least one coil arrangement, reinforced with electrically isolating particles in form of powder and/or paste, particularly with oil impregnated particles composed of or comprising paper material, and/or cellulose, and/or silicon.
The advantages in connection with the described method for a voltage transformer according to the present invention are similar to the previously, in connection with the voltage transformer for high voltages described advantages.
The present invention is further described hereinafter with reference to illustrated embodiments shown in the accompanying drawings, in which:
FIG. 1 illustrates a voltage transformer 1 for high voltages in section view, comprising a housing 2 and a coil arrangement 8, which is electrically insulated by an isolation material, and
FIG. 2 illustrates in section view the coil arrangement 8 of FIG. 1 according to the state of the art, with a stack 10 of layers of taped paper and wounded electric wires, wrapped by a paper sleeve 11, and
FIG. 3 illustrates in section view the coil arrangement 8 of FIG. 1 according to the present invention, with a stack 10 without wrapped paper sleeve 11, reinforced by isolation material comprising particles.
In FIG. 1 is in section view a voltage transformer 1 for high voltages shown. The voltage transformer 1 comprises a housing 2 and at least one coil arrangement 8, which is electrically insulated by an isolation material. The housing 2 comprises an isolator 3, for example in form of a hollow cylindrical body respectively tube, with a base plate 4 and a cover plate 5, for example in form of cylindrical metal plates air tight closing the interior of isolator 3, arranged on a pedestal, for example three or four pillars made of metals like steel and/or aluminum, and with a terminal box 7 arranged next to one side of the isolator 3, particularly for devices to control, measure, process, store and send values and/or data of the voltage transformer 1, particularly the coil arrangement 8.
Coil arrangement 8 is for example connected to ground via pedestal 6 and base plate 4, and connected to a high voltage, particularly to be transformed and/or measured, via electrical connections, particularly through cover plate 5 and a high voltage terminal at the cover plate 5. The high voltage terminal is designed to electrically connect the voltage transformer 1 respectively coil arrangement 8 with high voltage lines, electrical generators and/or electrical consumers, to transform and/or measure voltages of high voltage lines and/or devices. Coil arrangement 8 is for example arranged at a U-shaped magnet core, particularly comprising layered iron and/or steel sheets.
A particularly air tide tube, arranged between for example base plate 4 and terminal box 7, with electrical and/or optical wires connects devices to control, measure, process, store and send values and/or data of the voltage transformer 1 in terminal box 7 with the coil arrangement 8 and/or devices inside the housing 2 respectively the isolator 3 as for example sensors.
Isolator 3 comprises or consists of electric isolating material, particularly ceramic, silicone and/or composite materials, and is for example designed in form of a cylindrical hollow tube with circumferential plate fins at the outer surface of the isolator 3, to increase leakage current length at the isolator 3 outer surface. Isolation material, for example an insulating fluid, particularly gas and/or liquid, for example consisting of or comprising oil, particularly mineral oil and/or a synthetic oil, and/or ester, particularly vegetable esters, filled in the housing 2, is electrically isolating parts of the voltage transformer 1 like coil arrangement 8 from the housing 2. To save costs and space, housing 2 is built compact, with low spatial dimensions. In the state of the art, with an isolation by insulating fluid, particularly gas and/or liquid, with for example air and/or SF6 as gas or oil and/or esters as liquid, dimensions of the housing are in a range, making fault currents and/or arcs possible and probable. An additional electrical isolation of particularly high voltage coils of coil arrangement 8 is necessary for a safe, durable operation of voltage transformer 1 particularly without risk for service staff, without arcs and/or fault currents particularly across grounded parts of voltage transformer 1 like base plate 4, terminal box 7 and/or pedestal 6.
To ensure save operation and to ensure a further electrical isolation particularly of high voltage coils, in the state of the art coil arrangement 8 exhibits a design according to FIG. 2. The coil arrangement 8 comprises an alternating stack 10 of wounded electric wire layers and wrapped respectively taped paper electrically insulating adjacent electric wire layers, for example spooled on a core roll respectively wrapped/wind/taped on a cylindrical tube of nonmagnetic, electrically nonconductive material. The production process comprises providing for example a cylindrical tube/core of nonmagnetic, electrically nonconductive material, for example plastic, ceramic, wood, and/or a composite material, rotating the tube/core around a longitudinal axis and winding/spooling a wire, for example a copper wire, as coil, layer by layer or at least as a layer around the tube/core alternating with a paper tape, which is wrapped/spooled/taped layer by layer or at least as a layer around particular layers of wire.
Different coils can be produced on one tube by winding/spooling several wires, particularly at least two wires, spatial and electrically separated in one layer and/or separated by isolator material, particularly at least one or more layers of paper, layer by layer with one wire in a respective layer and another, spatial and electrically separated wire in another layer. Other forms are possible too, and/or other production methods like keeping the tube fixed and spooling the wire and paper around a fixed tube. Tube 9 can be part of coil arrangement 8 or can be removed at the end of the spooling process. In the embodiment of FIG. 2 tube 9 stays part of the coil arrangement 8, mechanically stabilizing and carrying the stack 10, and is not removed.
For high electrical isolation, paper can be impregnated with oil, for example transformer oil.
To ensure save operation and to ensure a further electrical isolation particularly of high voltage coils, in the state of the art as shown in FIG. 2, the coil arrangement 8 respectively outer shell of the coil arrangement 8 is wrapped with several layers of paper tape and/or sheets for example in form of a sleeve 11, particularly soaked with isolator fluid, for example transformer oil.
The wrapping process comprises to manually provide paper sheets or tape, mount it within the core respectively tube 9, with paper projecting on both sides outside the core respectively tube 9, cutting slices off projecting paper, and wrapping paper slices around the coil arrangement 8, to enwrap and electrically isolate the coil arrangement 8 particularly completely. A manual wrapping procedure with steps like cutting slices off paper takes much time, particularly days, is expensive due to manpower costs and suffers from human errors. Due to complex shapes of coil arrangements 8 and difficult cutting and wrapping steps, an automation of wrapping processes is not possible or at least difficult and expensive.
In the state of the art, only coil arrangements 8 with paper sleeves 11, as for example shown in FIG. 2, are able to be used in compact housings 2 for voltage transformers 1 at voltages higher than 71 kV, without a high risk of arcs and electric faults. A production of voltage transformers 1 as described before in an automated, preferably fully automated process, saving cost and manpower, is not possible.
According to the present invention, a voltage transformer 1 for high voltages, particularly higher than 72 kV, comprising a housing 2, particularly a compact housing as for 72 kV voltage transformers 1, is possible/designable with a coil arrangement 8 without paper sleeves 11, being able to be produced automated particularly fully automated, by reinforcing the electrical isolation within the housing 2, instead of wrapping coil arrangement 8 with paper sleeves 11, by the use of isolation material comprising particles in form of powder and/or paste.
This enables a use of coil arrangement 8 as shown in Fig. 3, which is similar to coil arrangement 8 as shown in Fig. 2 and as described before, except a wrapping with paper sleeves 11. This coil arrangement 8 is open towards the ends of tube 9 respectively comprises openings between layers of wrapped/taped paper. Wires in-between wrapped/taped paper bear the danger of arcs and/or fault currents due to the openings and missing isolation by paper sleeves 11 particularly towards the housing 2. A reinforcing of electrical isolation within the housing 2 by isolation material comprising particles in form of powder and/or paste, enables the use of a coil arrangement 8 according to FIG. 3, without paper sleeves 11, in voltage transformers 1, particularly with compact housing 2 and at high voltages, for example higher than 72 kV, without risking arcs and/or electrical faults.
Isolation material comprising particles in form of powder and/or paste is provided to the coil arrangement 8 during production, for example during winding/spooling a wire, for example a copper wire, as coil layer by layer or at least as a layer around the tube/core alternating with a paper tape, which is wrapped/spooled/taped layer by layer or at least as a layer around particular layers of wire. Particles are for example deposited during production in a bath with particles, and/or by spraying particles during wrapping/spooling/taping. Alternatively or additional, the housing 2 of the voltage transformer 1 is filled with particles and/or with oil comprising particles, for example completely filled, and particles in form of powder and/or paste diffuse respectively intrude into openings of the coil arrangement 8, particularly electrically isolating and/or closing the openings. The openings are filled with isolation material comprising particles in form of powder and/or paste, particularly completely electrically isolating filled by powder and/or paste, i.e. opening are filled completely and thereby closed, electrically completely isolating wires towards the housing 2 across former openings.
The particles are composed of or comprise paper material, and/or cellulose, and/or silicon. These materials show good dielectric properties, particularly good electrical isolation properties. To improve the isolation properties particles are impregnated by a fluid, particularly mineral oil and/or a synthetic oil, and/or ester, particularly vegetable esters. Alternatively, the fluid comprises a gas, for example synthetic air and/or SF6. Particles are for example in spherical form, and/or particles are in fibrous form.
Particle size is for example in the range of micro- and/or nano-meter, and/or the isolation material comprises particles with a size in the range of micro- and/or nano-meter. The described form and/or size allows a high fill factor and a high surface to volume ratio of particles, for example at least two times, particularly at least ten times higher than for the same material in form of sheets. A high surface to volume ratio improves impregnation with for example oil and increases with a high fill factor isolation properties.
Particles are filled into the housing for example through a particle filler inlet, not shown in FIG. 1, and or before closing the housing by cover plate 5. The filling process can be fully automated, saving time and costs. An impregnation of particles particularly by oil can be done before filling particles into the housing 2, producing a solution and/or slurry of particle material like paper material, and/or cellulose, and/or silicon in for example oil. An impregnation of particles can alternatively or additionally be done after filling particles into the housing 2. With time a solution and/or slurry can coagulate, consolidate and/or solidify, or stay fluidic, particularly forming a paste. The isolation material made of, respectively comprising particles, particularly impregnated by oil, results in a good electrical isolation of particularly the coil arrangement 8 towards the housing 2 of the voltage transformer 1, particularly at voltages higher than 72 kV.
The voltage transformer 1 is useable/suitable for voltages above 72 kV, particularly in the range of 123 kV to 300 kV and/or of 362 kV to 550 kV, with a compact housing 2 and without electric faults and/or arcs at these high voltages. A use at other voltages, for example higher than 550 kV, particularly up to 1200 kV, is possible too, particularly with higher dimensions of the housing 2.
The alternating stack 10 of wounded electric wire layers and wrapped paper electrically insulating adjacent electric wire layers, is reinforcing with an isolation material comprising particles in form of powder and/or paste to electrical isolate the coil arrangement 8 within the housing 2, with particles arranged within the alternating stack of wounded electric wire layers and wrapped paper electrically insulating adjacent electric wire layers, particularly in- between wires of a layer and/or in-between wrapped paper, and/or with particles arranged within the housing 2, filling free space between the housing 2 and the coil arrangement 8, particularly filling free space completely.
The above described embodiments of the present invention can be used also in combination and combined with embodiments known from the state of the art. For example, the voltage transformer 1 can be an inductive voltage transformer and/or a power voltage transformer. Particles of isolation material comprise paper material, and/or cellulose, and/or silicon or combinations of these materials. Alternative isolator materials in form of particles can be used too, particularly oil solvable materials like plastics and/or porous materials like zeolite, and/or materials like silicon oxide. Particles can be for example of spherical form, porous and/or fibrous. An impregnation of particles for example with oil can be done before filling the particles into the voltage transformer 1 or after filling the particles into the voltage transformer 1. Particles can be impregnated by an insulating fluid and/or embedded in fluid, particularly in liquid and/or gas, or fully or partly be solved in liquid. The insulating fluid can be or can comprise oil, particularly mineral oil and/or a synthetic oil, and/or ester, particularly vegetable esters, or gas, for example clean air and/or SF6. In the isolator 3, all free space can be filled with isolation material or only parts, particularly the coil arrangement 8 and/or electrical conductors are filled and/or coated with isolation material.
List of Reference Characters
1 voltage transformer
2 housing 3 isolator
4 base plate
5 cover plate
6 pedestal 7 terminal box 8 coil arrangement
9 winding tube
10 stack, particularly wrapped/taped paper and wounded electric wires
11 paper sleeve

Claims

Claims
1. Voltage transformer (1) for high voltages, comprising a housing (2) and at least a coil arrangement (8), with an alternating stack of wounded electric wire layers and wrapped paper electrically insulating adjacent electric wire layers, with an isolation material reinforcing the electrical isolation within the housing (2), characterized in that the isolation material comprises particles in form of powder and/or paste.
2. Voltage transformer (1) according to claim 1, characterized in that particles are impregnated by an insulating fluid and/or embedded in fluid, particularly liquid and/or gas.
3. Voltage transformer (1) according to claim 2, characterized in that the insulating fluid is or comprises oil, particularly mineral oil and/or a synthetic oil, and/or ester, particularly vegetable esters.
4. Voltage transformer (1) according to any one of the claims 1 to 3, characterized in that particles (14) are composed of or comprise paper material, and/or cellulose, and/or silicon.
5. Voltage transformer (1) according to any one of the claims 1 to 4, characterized in that particle size is in the range of micro- and/or nano-meter, and/or the isolation material comprises particles with a size in the range of micro- and/or nano-meter.
6. Voltage transformer (1) according to any one of the claims 1 to 5, characterized in that particles are arranged within the alternating stack of wounded electric wire layers and wrapped paper electrically insulating adjacent electric wire layers, particularly in-between wires of a layer and/or in- between wrapped paper.
7. Voltage transformer (1) according to any one of the claims 1 to 6, characterized in that particles are arranged within the housing (2), filling free space between the housing (2) and the coil arrangement (8).
8. Voltage transformer (1) according to any one of the claims 1 to 7, characterized in that particles are in spherical form, and/or particles are in fibrous form.
9. Voltage transformer (1) according to any one of the claims 1 to 8, characterized in that the voltage transformer (1) is useable for voltages above 72 kV, particularly in the range of 123 kV to 300 kV and/or of 362 kV to 550 kV.
10. Voltage transformer (1) according to any one of the claims 1 to 9, characterized in that the at least one coil arrangement (8), with an alternating stack of wounded electric wire layers and wrapped paper electrically insulating adjacent electric wire layers, is in form of a circular cylinder, with openings between wrapped paper layers towards circular base and/or cover side of the cylinder.
11. Voltage transformer (1) according to claim 10, characterized in that the openings are filled with isolation material comprising particles in form of powder and/or paste, particularly completely electrically isolating filled by powder and/or paste.
12. Method for a voltage transformer (1), particularly for a voltage transformer (1) according to any one of the preceding claims, characterized in that at least a coil arrangement (8), with an alternating stack of wounded electric wire layers and wrapped paper electrically insulating adjacent electric wire layers, is reinforced in electrical isolation properties by isolation material comprising particles in form of powder and/or paste.
13. Method according to claim 12, characterized in that the particles get impregnated in the voltage transformer (1), particularly in the housing (2) of the voltage transformer (1), after filling in the particles into the housing (2).
14. Method according to claim 12, characterized in that particles (14) get impregnated to create a pulp, particularly after degassing, and afterwards the pulp is filled into the voltage transformer (1) housing (2).
15. Method according to any one of the claims 12 to 14, characterized in that a voltage above 72 kV applied to the voltage transformer (1) is transformed by the at least one coil arrangement (8), reinforced with electrically isolating particles in form of powder and/or paste, particularly with oil impregnated particles composed of or comprising paper material, and/or cellulose, and/or silicon.
PCT/EP2019/076438 2019-09-30 2019-09-30 High voltage transformer and method to isolate parts of the voltage transformer WO2021063477A1 (en)

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Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2115113B2 (en) 1971-03-25 1976-01-22 Siemens AG, 1000 Berlin und 8000 München HV inductive voltage transformer - has vertical conductor insulation with embedded capacitance layers supported on oil filled base
JPH06204059A (en) * 1993-01-07 1994-07-22 Nissin Electric Co Ltd Primary coil of instrument transformer
WO2001091135A1 (en) * 2000-05-19 2001-11-29 Mcgraw Edison Company Electrical apparatus with synthetic fiber and binder reinforced cellulose insulation paper
US20050072964A1 (en) * 2003-10-02 2005-04-07 Rapp Kevin J. Additive for dielectric fluid
WO2006118536A1 (en) * 2005-05-04 2006-11-09 Abb Research Ltd. Electric insulation material, an electric device and a method for producing an electric insulation material
US20080179077A1 (en) * 2005-06-07 2008-07-31 Abb Research Ltd High-voltage bushing
WO2009146569A1 (en) * 2008-06-04 2009-12-10 Trench Switzerland Ag High-voltage measuring transducer with flexible insulation
EP2800113A1 (en) * 2013-04-29 2014-11-05 ABB Technology AG HV dry instrument transformer
EP2800112A1 (en) * 2013-04-29 2014-11-05 ABB Technology AG HV instrument transformer

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2115113B2 (en) 1971-03-25 1976-01-22 Siemens AG, 1000 Berlin und 8000 München HV inductive voltage transformer - has vertical conductor insulation with embedded capacitance layers supported on oil filled base
JPH06204059A (en) * 1993-01-07 1994-07-22 Nissin Electric Co Ltd Primary coil of instrument transformer
WO2001091135A1 (en) * 2000-05-19 2001-11-29 Mcgraw Edison Company Electrical apparatus with synthetic fiber and binder reinforced cellulose insulation paper
US20050072964A1 (en) * 2003-10-02 2005-04-07 Rapp Kevin J. Additive for dielectric fluid
WO2006118536A1 (en) * 2005-05-04 2006-11-09 Abb Research Ltd. Electric insulation material, an electric device and a method for producing an electric insulation material
US20080179077A1 (en) * 2005-06-07 2008-07-31 Abb Research Ltd High-voltage bushing
WO2009146569A1 (en) * 2008-06-04 2009-12-10 Trench Switzerland Ag High-voltage measuring transducer with flexible insulation
EP2800113A1 (en) * 2013-04-29 2014-11-05 ABB Technology AG HV dry instrument transformer
EP2800112A1 (en) * 2013-04-29 2014-11-05 ABB Technology AG HV instrument transformer

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