Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B17/00—Insulators or insulating bodies characterised by their form
  • H01B17/32—Single insulators consisting of two or more dissimilar insulating bodies
  • H01B17/325—Single insulators consisting of two or more dissimilar insulating bodies comprising a fibre-reinforced insulating core member
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B17/00—Insulators or insulating bodies characterised by their form
  • H01B17/42—Means for obtaining improved distribution of voltage; Protection against arc discharges
• • 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
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49002—Electrical device making
  • Y10T29/49227—Insulator making

Definitions

• the invention relates to a field-controlled composite insulator comprising a rod or tube as insulator core made of fiber-reinforced plastic, which is coated with a screen cover and equipped at its ends with fittings.
• the materials of an insulator are heavily loaded by the inhomogeneous distribution of the electric field across its surface.
• One of the causes lies in the structural design of an insulator.
• the field strength changes due to the transition from the insulating materials of the screens and the insulator core to a metallic material, because of the transition to ground potential at the mast crossbar or conductor potential, where the conductors are attached.
• the so-called geometric field control can be used. By rounding corners and edges, the geometry of the workpieces, in particular the parts carrying the tension, is defused.
• insulating materials such as plastics such as epoxy resins and polymers
• deposits of dielectric and / or ferroelectric materials applied as field control layers.
• the shielding element and optionally the core are each made of a semiconducting material.
• the semiconductor capability of the shield shell and the core are the same at each point of the insulator.
• the screen cover must be additionally coated with a protective layer.
• the composite insulator according to the invention has at least in the region of the conductor-side fitting on the rod or tube of the insulator core on a field control layer which is enclosed by the valve.
• Leitlack, metal rings or wire mesh are produced. Outside the fixture, the field control layer is surrounded by a protective layer or directly by the screens extruded seamlessly on the core.
• the insulator core as a pipe or rod is usually made of a fiberglass-reinforced thermoset such as epoxy or polyester resin.
• the invention is suitable for all types of composite insulators, in particular for suspension insulators, post insulators or conduit insulators.
• the field of application starts at high voltages above 1 kV and is particularly effective at voltages above 72.5 kV.
• the field control layer is usually made of the same material as the protective layer covering it. But the protective layer can also advantageously consist of a higher erosion and Kriechstromfesten material.
• the protective layer is in any case made of a material with high insulation properties. Materials with these properties are elastomeric materials, for example, polymeric plastics such as silicone rubber (HTV) of hardness classes Shore A 60 to 90 or ethylene-propylene copolymer (EPM).
• HTV silicone rubber
• EPM ethylene-propylene copolymer
• the screens are pushed, which may consist of the same material as the protective layer.
• the protective layer and the screens can also be extruded onto the core in one and the same operation from the same material, as is known from the patent EP 1147525 B1.
• the field control can be resistive or capacitive or in combination with each other. For this purpose, the material of the field control layer is filled with particles as filler, which cause the field control.
• a field control layer with ohmic conductive (conductive) and / or semiconducting (semiconductive) fillers is provided.
• conductive conductive
• semiconducting fillers the linear material dependence between voltage and current is utilized.
• the conductive fillers include, for example, carbon black, Fe 3 O 4 and other metal oxides.
• microvaristors are particularly suitable for resistive field control. These are varistors in powder form with grain diameters between 50 nm and 100 ⁇ m. With a suitable design, it can be achieved that a material filled with microvaristors, in particular a silicone material, exhibits high electrical conductivity and low power dissipation in continuous operation under impulse voltage stress.
• Capacitive field control uses materials with dielectric properties such as TiO 2 , BaTiO 3 or TiO x . These materials have a high dielectric constant (permittivity).
• Refractive field control is a special form of capacitive field control.
• the field lines are refracted at the transitions of the materials so that local field disturbances, in particular field strength peaks, are eliminated as far as possible.
• the field control layer may consist of one layer or multiple layers, wherein the individual layers may have different field control properties.
• the particles which are added as fillers to the layers of the field control layer have a diameter of 10 nm up to 100 ⁇ m, preferably in a range of 0.1 ⁇ m to 10 ⁇ m. Their size depends on the thickness of the layer and the intensity and extent of the expected field disturbance.
• the proportion of particles is between 50 and 90% by weight, preferably 70%.
• the proportion of particles, the degree of filling, may be above the percolation limit, i. that the particles are in direct electrical contact.
• the thickness of a layer of a field control layer may be 1 mm to 5 mm, usually 2 mm to 3 mm. It depends on the intensity and extent of the expected field disturbance.
• the field control layer can consist of one layer and contain only resistive particles as filler. Such a layer is provided at the locations of the insulator to which preferably a resistive, an ohmic field control is required.
• the field control layer can consist of one layer and contain only capacitive particles as filler. Such a layer is provided at the locations of the insulator to which preferably a capacitive, or in particular a refractive, field control is required.
• the field control layer may consist of one layer and the proportion of the resistive or capacitive particles may be different over the length of the layer. With the same thickness, the intensity of the effect on the field disturbances can be changed locally by changing the proportion of fillers in the position.
• the Change in the proportion of the filler is possible if the filler has not already been added to the material of the layer before application, but only in or before the nozzle for applying the layer is admixed to the material.
• the thickness of a layer of a field control layer can change over its length. This is possible by changing the feed rate within the extruder, which applies the layer to the core. With the same proportion of fillers can be changed locally by changing the thickness of the layer and thus the number of particles in the position of the intensity of the effect on the field disturbances.
• the field control layer can also consist of at least two layers with resistive or capacitive particles as fillers.
• the one layer may have a higher proportion of resistive or capacitive particles than the other layer.
• the field control layer can also consist of at least two layers, one layer containing exclusively resistive and another layer exclusively capacitive particles. For several layers one above the other, the layers may alternate in their order.
• the field control layer may consist of one layer and contain a mixture of resistive and capacitive particles.
• the field control layer can also consist of at least two layers, wherein one layer contains a mixture of resistive and capacitive particles and the other layer contains only resistive or capacitive particles.
• the layers may alternate in their order or composition in terms of their effect on the electric field.
• the proportion of capacitive and / or resistive particles in the individual layers of the layer may be different.
• the field control layer can be applied over the entire length of the insulator core. However, it can also extend only over partial areas, such as in the field of fittings.
• the field control layer can also be divided into individual sections and thereby interrupted.
• one layer may be longer than the other bordering the layerless section and extending beyond the layer above or below to the non-layered section, so that the field influencing character of this situation comes exclusively to effect.
• the individual layers of a field control layer can be separated from one another by insulating intermediate layers if differences in the conductivity in the contact region of the two layers themselves could lead to undesired changes in the field.
• microvaristors are preferred, in particular ZnO.
• this can with a protective layer, such as an insulating HTV silicone extrudate layer with extremely good Leakage, erosion and weathering resistances, coated on which then the screens are pushed.
• This protective layer increases the outdoor resistance and can be up to 5 mm thick, advantageously between 2 mm and 3 mm.
• the field control layer can be applied to the core by an extruder through which the core is pushed. If a layer with several layers is to be applied to the core, this can be done by a multi-stage nozzle or by several extruders arranged one behind the other. The application of the layers must be such that they adhere well to the insulator core and join together to form a layer. If necessary, the application of Haftverrnittiern required.
• the invention offers the possibility of using a field control layer only at those points where critical disturbances of the electric field, in particular field strength peaks, can occur. As a result, the power losses at the insulators can be reduced to minimum values.
• Variation of the overlap lengths of the layers can advantageously be adapted to the field disturbances to be eliminated, in particular field strength peaks, in particular caused by local soiling.
• the field distribution along the insulator is thereby made uniform. This avoids the formation of corona discharges, corona discharges and flashovers, which prevents premature aging of the material.
• FIG. 1 shows a detail of a composite insulator with a field control layer, consisting of a layer, in longitudinal section,
• FIG. 2 shows a section of a composite insulator with a field control layer of two layers, wherein a layer covers only a part of the core
• FIG. 3 shows a long-rod insulator, in which the areas are marked in which a field control layer is applied
• FIG. 4 shows a long-rod insulator in which a field control layer is applied in the region of the fitting to which the conductor cables are fastened
• FIG. 5 shows the transition region from an insulator core to a fitting in longitudinal section
• FIG. 6 shows a comparison test between a conventional insulator according to the invention and a conventional insulator when the ac voltage is present under irrigation; and
• FIG. 7 shows a flowchart for explaining the production of an insulator according to the invention.
• FIG. 1 shows a longitudinal section through a composite insulator 1 according to the invention.
• it is the section of a long-rod insulator.
• a field control layer 3 is applied on a core 2 made of glass fiber reinforced plastic.
• it can have capacitive or resistive properties.
• it may contain ZnO microvaristors for resistive field control.
• the field control layer 3 is covered by a protective layer 4, which consists of an erosion and Kriechstromfesten material and the field control layer 3 protects against weathering and pollution.
• the screens 5 are arranged at regular intervals, which are injected from one of the known polymeric plastics.
• the field control layer 3 in a portion of the insulator 1 of two layers 31 and 32, of which the layer 32 is disposed over the continuous layer 31.
• the two layers 31 and 32 may have different field control properties.
• the outer layer 32 may have capacitive and the continuous layer 31 resistive properties.
• Such an arrangement of the layers may be advantageous, for example, in the field of fittings in terms of constructive field disturbances.
• the field control layer 3 is uniformly thick throughout. In the area where the field control layer 3 is double-layered, by reducing the extrusion, the inner layer 31 can be thinned.
• the outer layer 32 can be applied so thick that a uniform, uniform layer thickness is achieved.
• Figures 3 and 4 show long-rod insulators 10, as used for example in high-voltage overhead lines.
• the structure of the field control layers of these insulators may correspond, for example, to the structure as described in the insulators illustrated in FIGS. 1 or 2.
• the insulators 10 each depend on a traverse 11 of a high-voltage mast, not shown here.
• the attachment takes place in a known manner with a fitting 12 made of metal.
• the conductor cables 14 are fastened by means of a further armature 13.
• the isolators 10 which have a length of 4 m, to avoid excessive power losses either only partially, as shown in FIG.
• the insulator 10 in FIG. 3 has five equally sized regions 15, in which the core is coated with a field control layer. They are each interrupted by areas of equal size without field control layer.
• the insulator 10 in FIG. 4 has a region 16 which is provided with a Field control layer is coated and extending from the armature 13, to which the conductors 14 are fixed, over one third of the rod length upwards.
• FIG. 5 shows a schematic representation of a transition region from a fitting to the shield sheath region in longitudinal section. It is a section through the end of an insulator with a fitting to which the conductors are attached, as shown in Figures 3 or 4. Matching features with Figures 2, 3 and 4 are designated by the same reference numerals.
• the core consists of a rod 2 made of glass fiber reinforced plastic, which is coated with a field control layer 3, which in turn is enveloped by a protective layer 4. On this protective layer, the umbrellas 5 are raised.
• the field control layer 3 corresponds in its construction to that shown in FIG.
• the end of the rod 2 is enclosed by the fitting 13.
• a layer 31 completely covers the core 2 of the insulator on the length visible in the illustration. It is a layer with resistive effect and contains microvaristors.
• the capacitive field control is particularly suitable to reduce field strength peaks that are constructive, for example, by edges or stepped transitions, as they occur at the transition from a fitting to the insulator.
• To improve the conductive contact between the layers and the fitting of the core enclosing cavity of the fitting may be coated with a conductive paint. Also deposits of wire loops or wire nets are, as not shown, possible.
• FIG. 6 shows the result of a comparison test between a long-rod insulator according to the invention, the surface of which was coated with a field control layer according to FIG. 1, and a conventional long-rod insulator as reference insulator, which was equipped exclusively with HTV silicone without field control layer.
• the umbrellas were each made of HTV silicone. The striking distance was 2765 mm.
• a 3 mm thick polymer layer cross-sectional area: 1.8 cm 2
• the polymer layer for field control were microvaristors, ZnO varistors in powder form, in a proportion of 50 to 90% by weight, preferably 70% by weight with a particle size of 10 nm to 100 ⁇ m, preferably between 0.1 ⁇ m and 10 microns have been added.
• the degree of filling of the microvaristors was above the percolation limit, ie the microvaristors were in direct electrical contact with each other.
• the reference insulator according to the invention can be seen on the left and the reference insulator on the right during the comparison test.
• an applied AC voltage of 750 kV (effective) the insulators were irrigated.
• the reference insulator shows strong discharge activity among the bottom five shields facing the conductor side, the isolator equipped with the Fald Kunststoff is completely discharge-free.
• FIG. 7 shows a flow chart for explaining the production of an insulator according to the invention.
• the core 2 of the insulator to be produced is a rod which consists of a glass fiber reinforced plastic. This rod 2 is guided in the feed direction 20 by successively arranged stations, where it is completed to the insulator.
• a bonding agent 211 is applied so that the layers of the field control layer 3 to be subsequently applied are intimately joined to the core 2.
• a first layer 31 of the field control layer is applied, for example a layer with varistors, a layer with resistive character. If another layer is to follow, another extruder 23 is provided for applying the further layer 32, for example a layer with a capacitive character.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Insulators (AREA)
• Insulating Bodies (AREA)

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Citations (5)

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• 2008
  • 2008-02-14 DE DE102008009333A patent/DE102008009333A1/de not_active Withdrawn
• 2009
  • 2009-02-12 WO PCT/EP2009/000983 patent/WO2009100904A1/de not_active Ceased
  • 2009-02-12 EP EP09709505A patent/EP2243145B1/de active Active
  • 2009-02-12 PL PL09709505T patent/PL2243145T3/pl unknown
  • 2009-02-12 JP JP2010546261A patent/JP5302978B2/ja not_active Expired - Fee Related
  • 2009-02-12 CA CA2715651A patent/CA2715651C/en active Active
  • 2009-02-12 ES ES09709505T patent/ES2401885T3/es active Active
  • 2009-02-12 SI SI200930550T patent/SI2243145T1/sl unknown
  • 2009-02-12 DE DE202009018686U patent/DE202009018686U1/de not_active Expired - Lifetime
• 2010
  • 2010-08-16 US US12/856,806 patent/US8637769B2/en not_active Expired - Fee Related

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