JP2016501000A - Lightning arrestor - Google Patents

Abstract

The present invention includes an arrester element (2), a control hood (3) electrically connected to the arrester element (2), and a fluid-tight housing (3) in which the arrester element (2) and the control hood (3) are disposed. 4) and a lightning arrester (1). The arrester element (2) has a ground contact (5) and a high voltage contact (6), and the ground contact and the high voltage contact electrically connect the inside of the housing (4) to the outside. According to the invention, the control hood (3) has a first partial hood (10) and a second partial hood (11), the first partial hood (10) and the second partial hood (11) being electrically connected to each other. Connected to each other and movable relative to each other so that an electrical connection from the ground contact (5) to the high voltage contact (6) can be established or interrupted via the arrester element (2). In this way, the insulation point inside the housing (4) can be opened and closed. [Selection] Figure 2

Description

  The invention relates to a lightning arrester according to the premise of claim 1.

  A lightning arrester is, for example, a protection system for a switch assembly, but such a system discharges the overvoltage to ground in the event of an overvoltage as a result of a lightning strike or other subsystem malfunction, thereby switching the switch. Protect other components of the assembly.

  Such lightning arresters comprise one or more cylindrical arrester elements, which have a varistor array constructed from similar individual cylindrical varistor elements. Varistor elements are characterized by a voltage dependent resistance. At low voltage, the varistor element acts as an insulator. A varistor element exhibits good conductance when a certain threshold voltage depending on the material is exceeded. Varistor elements are often made from metal oxides such as zinc oxide. The arrester elements are closed at both ends with end fittings that provide electrical contact with the switch assembly and ground. In order to ensure good electrical contact even under mechanical loads, the varistor rows need to be put together under pressure. This can be done by means of a tension element, preferably made of glass fiber reinforced plastic, such as a cable or a rod, fixed in the end fitting by tension. The tension element in this case surrounds the varistor row and forms a cage so as to surround the varistor row.

  For use in a gas insulated switchgear assembly, the lightning arrester has a fluid tight housing that surrounds the arrester element. In this case, in order to increase the dielectric strength, the casing is filled with a fluid that is usually sulfur hexafluoride. The housing is usually made of metal and is electrically grounded. One end fitting of the arrester row is grounded via a contact passing through the housing. The other end fitting is electrically connected via a bushing to a contact located on the outside of the housing, which contact is used as a connection to the switch assembly. Specifically, a relatively large lightning arrester often has a control hood at the end of the high voltage side, and this control hood has a cylindrical shape with one end closed and is fitted to the end of the arrester row. Individual varistor elements have a high capacitance when grounded, but series circuits that include varistor elements result in a very low series capacitance, whereby the varistor array exceeds a certain physical length. Produces an inhomogeneous voltage distribution. Therefore, the varistor element is exposed to a high voltage load at a portion farther from the ground potential of the varistor row, and its resistance effect may cause undesirable heating. In this way, the control hood will serve for the purpose of equalizing the voltage distribution along the length of the varistor array.

  When attempting to electrically test a switch assembly, it is necessary to disconnect the lightning arrester from the switch assembly because of the high voltage that occurs at that time. Otherwise, the lightning arrester will discharge the voltage to ground and the measurement result will be incorrect.

  To date, lightning arresters having a break point are known, at which the lightning arrester can be disconnected from the switch assembly. In order to operate this cutting point, it is necessary to open the housing, and as a result, sulfur hexafluoride may come out. Since sulfur hexafluoride is a harmful greenhouse gas, it is highly undesirable to open the housing and is therefore inconvenient.

  JP 103222822-A discloses a general-purpose lightning arrester, but in this type, a switchgear is provided with an arrester train and a control hood, and the electrical connection is established or interrupted by moving them together. The arrester row is disconnected from the assembly.

In this case, in order to operate, linear movement is performed while maintaining airtightness by the housing wall.

  International Application No. PCT / EP2012 / 059973 discloses a lightning arrester capable of moving the control hood towards the arrester element and thereby opening and closing the cutting point.

  One disadvantage of the prior art is that it is necessary to move relatively large objects. It is an object of the present invention to define a lightning arrester that can be accomplished with smaller object movements.

  This object is achieved by the invention according to claim 1.

  Thus, the lightning arrester has an arrester element, a control hood electrically connected to the arrester element, and a fluid-tight housing in which the arrester element and the control hood are arranged. In this case, the housing has a ground contact and a high voltage contact, and the ground contact and the high voltage contact each electrically connect the inside of the housing to the outside. According to the invention, the control hood has a first part hood and a second part hood so that the electrical connection between the ground contact and the high voltage contact can be established or interrupted via the arrester element. The first part hood and the second part hood are electrically connected to each other and can move relative to each other. Thus, one of the partial hoods can be fixed, and only the other hood may be movable, thereby reducing the object to be moved.

  In an advantageous configuration of the invention, the first part hood and the second part hood are cylindrical and one can be telescopically pushed into the other. As a result, good axial guidance is provided.

  Desirably, the first partial hood is connected to the end fixture on the high voltage side of the arrester element, and the second partial hood is movable relative to the first partial hood in the axial direction of the arrester element. Since the first part hood cannot move, it may be optimized for the purpose of field control. The movable second part hood is movable in the axial direction of the arrester element relative to the first part hood, thereby allowing contact with the high voltage contact to close the contact, or vice versa, Realizes the function to open and close the contacts.

  Furthermore, the second part hood preferably has a recess on its end side, and a correspondingly shaped ridge on the high-voltage contact, and this recess is planar contact by placing the ridge in the recess. Can be formed. The second partial hood has, for example, a recess having a concave outer shape, and the high voltage contact may have a raised portion having a convex outer shape. Desirably, these outer shapes are rotationally symmetric with respect to the axial direction of the arrester element. In this case, the outer shape may be spherical or conical. It is also conceivable that one of the outer shapes is conical and the other is spherical. As the second partial hood is moved in the direction of the high voltage contact and approaches a distance or more relative to each other, the ridges enter the recesses. When the second part hood and the high voltage contact are in contact with each other, a planar contact point is formed, thereby allowing a particularly good contact. If one of the outlines is conical and the other is spherical, an annular contact area is created due to the overall hardness of the material. In all cases, such a cutting point is self-centering, i.e., a slight deviation of the direction of movement from the axial direction can be tolerated.

The present invention will be described in more detail with reference to the following drawings.
1 shows a lightning arrester with an open cut according to the present invention. Fig. 2 shows a lightning arrester with a closed cutting point according to the invention. Fig. 5 shows the area around the end fitting on the high voltage side of the lightning arrester according to the invention.

  In all the drawings, the same reference numerals are assigned to the components corresponding to each other.

  FIG. 1 shows a lightning arrester 1 having an open cut point 17 according to the invention. In this case, the lightning arrester 1 has a gas-sealed housing 4. In this case, the housing 4 is shown in an incised state in all drawings for the sake of clarity. The housing 4 is cylindrical, and one side is closed by a housing cover 16. In the operation ready state, the housing 4 is normally filled with an insulating fluid such as sulfur hexafluoride under high pressure. The ground contact 5 (not shown here) passes the electrical connection from the outside to the inside of the housing 4 through the housing cover 16. In this case, the electrical connection can be established by means of the conductive cover 16, or can be established by a bushing that is electrically insulated from the cover, for example as described in EP 12 170 022.3. . The high voltage contact 6 is arranged at the end of the housing 4 opposite the cover 16, where the high voltage contact is shown as a high voltage bushing. This high voltage bushing is suitable for high voltages from 1 kilovolt to several hundred kilovolts depending on the application and provides an electrical connection insulated from the housing 4.

  The arrester element 2 is disposed inside the housing 4. The arrester element comprises a cylindrical varistor array 7, a ground side end fitting 8, a high voltage side end fitting 9 (not visible here), and a plurality of tension elements 14. Varistor row 7 includes similar individual cylindrical varistor blocks. The end fittings 8, 9 are usually made of a conductive material. The tension element 14 is pushed into the end fittings 8 and 9 under tension, thereby holding the varistor row 7 together. The holding disks are inserted into the varistor row 7, but these holding disks have holes, and the tension element 14 passes through these holes, so that the arrester element 2 is stabilized. The longitudinal axis 18 of the varistor row defines the axial direction.

  The upper surface of the housing 4 is closed by a simple housing cover 16 on the ground connection side of the arrester element 2. The ground contact 5 is passed from the inside of the housing 4 to the outside through the housing cover 16 so as to be electrically insulated, and is used to connect to the ground. The ground contact 5 is connected to the arrester element 2 inside the housing 4 such as a cable so as to have conductivity. The grounding side end fitting 8 of the arrester element 2 is fixed to the housing cover 16. The housing cover 16 is electrically insulated from the varistor row 7. The housing cover 16 typically has a connection (not shown here) through which fluid, for example sulfur hexafluoride, can be introduced into the housing 4 or discharged out of the housing. .

  In order to pass a high voltage potential from the outside of the housing 4 without risk of flashover between the high voltage and the grounded housing 4, the upper surface of the housing 4 is connected to the high voltage connection side of the arrester element 2. The high voltage contact 6 is provided in the form of a high voltage bushing.

  The substantially cylindrical control hood 3 is fitted to the end of the arrester element 2 on the high voltage side.

  In this case, the control hood 3 includes a first partial hood 10 and a second partial hood 11. One of the two partial hoods is telescopically pushed into the other. The second part hood 11 is connected to a moving device 15, which in this case is illustrated as a push rod. The moving device 15 is passed through the housing cover 16 in a fluid-tight state, and can operate a cutting point from the outside of the housing 4. The operator moves the second partial hood 11 axially to the high voltage contact 6 until the cutting point 17 is finally closed (as shown in FIG. 2) without opening the housing 4. The mobile device 15 can be used. In this way, electricity between the high voltage contact 6 and the ground contact 5 via the second partial hood 11, the first partial hood 10, the high voltage side end fitting 9, the varistor row 7 and the ground side end fitting 8. Connection is established. If the second part hood 11 is moved in the opposite direction, i.e. away from the high voltage contact 6, the cut point 17 is opened, thereby opening the electrical connection.

  In order to ensure good contact between the high-voltage contact 6 and the second partial hood 11, the partial hood 11 is provided with a recess 12, in this case illustratively a spherical recess, on its end side. The raised portion 13 of the high voltage contact 6, which is also spherical in this case, enters the recess 12 until contact is finally established between the second partial hood 11 and the high voltage contact 6. In this case, the axes of the spherical ridge 13 and the recess 12 have the same center so as to compensate for the tolerance in the direction of movement.

  FIG. 3 shows the end of the arrester element 2 with the control hood 3 on the high voltage side. The control hood 3 is in this case shown in cross-section to show the high-voltage side end fitting 9. In this case, one of the first partial hood 10 and the second partial hood 11 is telescopically pushed into the other. In this case, the second partial hood 11 is around the outside of the first partial hood 10. The high voltage side end fitting 9 can be found in the control hood 3. The tension element 14 is compressed there. The moving element 15 is a push rod, is passed through the opening in the end fitting 9 on the high voltage side, and is connected to the second partial hood 11 on the end side. The first hood 10 has a cylindrical shape with both ends open to prevent concentration of the lines of force, and a thickened portion at the lower end when lowered. The first partial hood 10 is also fixedly connected to the end fitting 9 on the high voltage side. A sliding element (not shown here) can be placed between the first partial hood 10 and the second partial hood 11 in order to reduce friction and ensure good guidance. The second partial hood 11 is movable by the moving device 15 toward the first partial hood 10 in the direction of the longitudinal axis 18. The electrical connection between the first part hood 10 and the second part hood 11 can be established, for example, by a flexible connector.

The end face of the housing 4 is closed by a simple housing cover 16 on the ground connection side of the arrester element 2. The ground contact 5 is passed from the inside of the housing 4 to the outside through the housing cover 16 so as to be electrically insulated, and is used to connect to the ground. The ground contact 5 is connected to the arrester element 2 inside the housing 4 such as a cable so as to have conductivity. The grounding side end fitting 8 of the arrester element 2 is fixed to the housing cover 16. The housing cover 16 is electrically insulated from the varistor row 7. The housing cover 16 typically has a connection (not shown here) through which fluid, for example sulfur hexafluoride, can be introduced into the housing 4 or discharged out of the housing. .

Claims (4)

Arrester element (2),
A control hood (3) electrically connected to the arrester element (2);
The arrester element (2) and the control hood (3) are arranged, and have a ground contact (5) and a high voltage contact (6), and the ground contact and the high voltage contact are respectively in the housing (4). A fluid tight housing (4) for electrically connecting the interior of the interior to the exterior;
A lightning arrester (1) including
The control hood (3) has a first partial hood (10) and a second partial hood (11), and the first partial hood (10) and the second partial hood (11) are electrically connected to each other. Connected and movable relative to each other such that an electrical connection between the ground contact (5) and the high voltage contact (6) can be established or interrupted via the arrester element (2),
A lightning arrester (1). The first and second partial hoods (10, 11) have a cylindrical shape, and one can be telescopically pushed into the other.
A lightning arrester (1) according to claim 1, characterized by: The first partial hood (10) is connected to the end fitting (9) of the arrester element (2) on the high voltage side, and the second partial hood (11) is connected to the first partial hood (10). Is movable in the axial direction of the arrester element (2),
The lightning arrester (1) according to any one of claims 1 and 2. Said 2nd partial hood (11) has a recessed part (12) in the edge part side, and the said recessed part puts the protruding part (13) in the said recessed part (12), and thereby the said high voltage contact (6) ) In flat contact with the correspondingly raised ridge (13),
A lightning arrester (1) according to any one of claims 1 to 3, characterized in that.

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