Field probe combination for use in medium and high voltage

Abstract

The present invention relates to a field probe assembly for use in medium and high voltage applications, a bushing for medium and high voltage switchgear having one or more such field probe assemblies, and a switchgear having one or more such bushings.

Description

Technical Field

[0001] The present invention relates to a field probe assembly for use in medium and high voltage applications, a bushing for medium and high voltage switchgear having one or more such field probe assemblies, and a switchgear having one or more such bushings. Background Technology

[0002] Traditional current and voltage converters downsample thousands of volts or amperes from medium-voltage distribution networks to orders of magnitude more easily measurable. However, conventional measurement converters are designed and tested only for a fundamental frequency of 50 or 60 Hz. The permissible magnitude and angular errors are limited to a narrow frequency band near the rated frequency of 50 or 60 Hz. It is known, especially for conventional inductive current and voltage converters with iron cores and copper windings, that additional higher frequencies are transmitted very inadequately and result in very high measurement errors due to resonant amplification or attenuation.

[0003] However, since it is also the part that provides information about the status of the power supply or distribution network at a higher frequency, capacitive voltage dividers have attracted attention.

[0004] Alternatively, a field probe made of capacitive voltage divider, such as a streckmetall plate or conductive plastic, can be used. In addition to the measuring device, a so-called voltage indicator is usually connected to this field probe, which is often required in specifications, especially for indicating the absence of voltage.

[0005] Metal mesh is widely accepted for voltage measurement because field probes made of metal mesh can be designed with very thin walls, approximately 0.5 mm, and do not require draft angles compared to conductive plastics. Wall thicknesses less than 1 mm are also acceptable. For example, field probes made of stainless steel also exhibit good adhesion to casting resin. To ensure dielectric strength (or withstand voltage) between the measuring field probe and the grounded second field probe, a specific distance is required depending on the voltage level. Shape deviations of the flexible field probe made of metal mesh and tolerances arising from positioning in the casting resin tool must also be considered. Consequently, capacitive voltage dividers, including the shield, require >2 mm of radial mounting space. In medium voltages up to 40.5 kV, this is typically around 5 mm. The 2x5 mm requirement for voltage measurement necessitates shrinking the cross-section of the main current path in the field probe area. Therefore, due to standardization, solutions for primary rated currents of 630 A are currently only available in some bushings; solutions based on this technology are not yet known for primary currents of 1250 A or higher, as the shrinkage and power losses resulting from it are impossible to maintain the field widths commonly found in the market.

[0006] Current and voltage converters are known from the prior art, and they are formed from metal-coated circuit boards. Such an arrangement is disclosed in publication DE2409595.

[0007] The problem with this type of capacitive voltage divider is that the field probes, radially arranged around the main conductor, must always maintain a specific distance from the main conductor to ensure the dielectric strength of the main conductor under high voltage. The electric field strength must not exceed the limit value depending on the dielectric material.

[0008] In the example of SF6 DE2409595, the dielectric constant of the dielectric, i.e., Epsilon r, also fluctuates depending on the temperature and moisture content of the dielectric. As a result, the measurement results also fluctuate and the measurement accuracy decreases. Summary of the Invention

[0009] One of the problems to be solved is improving measurement accuracy.

[0010] In addition, buyers of switchgear are very price-sensitive, and the materials used contribute significantly to the price of switchgear.

[0011] Therefore, the problem to be solved is to provide a field probe that uses less material.

[0012] The problem is that, in addition to being exposed to variable electromagnetic fields, switching devices are also exposed to other variable boundary conditions, such as temperature changes.

[0013] Therefore, the problem to be solved is to shield the field probe in as many ways as possible to prevent external interference, especially variable interference, or to reduce the impact of interference.

[0014] Under all circumstances, the field width must not be significantly increased, especially in the case of medium-voltage equipment.

[0015] Of all these issues, it should be noted that when using field probes and grounded field probes, the minimum distance must always be observed, and heating limits, especially at the contact points, must be observed, which are also revisited in accordance with the corresponding standards in both cases.

[0016] Therefore, the technical problem to be solved by the present invention is to provide an improved field probe assembly, an improved bushing having at least one such field probe assembly, and a switching device having one or more such bushings having at least one such field probe assembly.

[0017] This technical problem is solved by the following technical solution.

[0018] The embodiments relate to a field probe assembly for use in medium and high voltage applications. The field probe assembly includes a first field probe and a second field probe, wherein the first and second field probes are formed by a first conductive field probe layer for the first field probe applied to an insulator and a second conductive field probe layer for the second field probe applied to an insulator. The insulator has the shape of a hollow cylinder or a hollow cylinder with a slit (or slot) opened parallel to the axis of symmetry of the field probe assembly. The insulator has an insulating thickness perpendicular to the axis of symmetry, i.e., in the radial direction, which separates the first conductive field probe layer from the second conductive field probe layer.

[0019] The first conductive field probe layer is arranged on a first side of the insulator, which points radially toward the interior of the hollow cylinder, and the second conductive field probe layer is arranged on a second side of the insulator, which points radially outward on the hollow cylinder. The first conductive field probe layer has a first contact device and the second conductive field probe layer has a second contact device.

[0020] In view of this disclosure, the terms "hollow cylinder," "hollow cylindrical shape," or "of a hollow cylindrical shape" should always include the shape of a slit hollow cylinder, and in particular, a fully slit hollow cylinder, i.e., a hollow cylinder lacking a continuous segment of a side parallel to the axis of symmetry of the field probe assembly. In view of this disclosure, the term "conductive" refers to electrically conductive, and the terms "insulating," "insulated," or "insulator" refer to electrically insulating.

[0021] The combination of an insulator, especially a flexible insulator, with two field probes achieves accurate positioning and orientation, particularly when there is a fixed insulating distance between the field probes.

[0022] Another advantage is that, in this structural configuration, only one component, namely the field probe assembly, must be cast or encapsulated, which reduces the production cost of the casing used for this field probe assembly.

[0023] Preferably, the field probe assembly is combined with the primary conductor of the bushing under medium or high voltage to form a capacitive voltage divider, thereby applying a harmless and measurable voltage at the second contact device through the grounding of the first contact device.

[0024] It is also preferred that the insulators of the applied first field probe and the second field probe be flexibly designed.

[0025] In the sense of this disclosure, flexibility is a moving structure, that is, a structure that can be reversibly deformed by force, and is in particular not a rigid structure. Such a structure can be reinforced, strengthened, or stiffened by further measures or components, thereby making these structures less flexible or more rigid.

[0026] Preferably, the first conductive field probe layer is arranged on the inner side of the hollow cylindrical insulator and the second conductive field probe layer is arranged on the outer side of the hollow cylindrical insulator.

[0027] Preferably, the support structure applied to the insulator supports the field probe assembly in a manner that preserves the hollow cylindrical shape. This support particularly relates to reinforcing the otherwise flexible field probe assembly.

[0028] Preferably, the support structure is arranged circumferentially at the opening edge of the hollow column of the insulator.

[0029] Particularly preferred is that the support structure is arranged circumferentially at the opening edge of the hollow column of the insulator, such that the support structure does not contact the first field probe and / or the support structure does not contact the second field probe; in particular, a sufficient insulating distance is provided between the first conductive field probe layer and the support structure and / or between the second conductive field probe layer and the support structure.

[0030] Preferably, the support structure is formed of conductive plastic and is circumferentially arranged at one or both open edges of the hollow cylinder of the insulator. Particularly preferred in this regard is that the support structure made of conductive plastic is further designed as a control electrode. This design as a control electrode also allows for a reduction in the distance between the field probe assembly and the primary conductor, whose electric field should be detected. If the control electrode is set at ground potential, it can be conductively connected to the second conductive field probe layer or have its own ground connection. If the control electrode is set at an intermediate potential, it must be sufficiently electrically insulated from the first and / or second conductive field probe layers.

[0031] Particularly preferred is that the support structure is formed of conductive plastic and is circumferentially arranged at one or both opening edges of the hollow cylinder of the insulator. The first conductive field probe layer has a support structure contact area at the opening edge or both opening edges, particularly a gold-plated or silver-plated support structure contact area. Preferably, this support structure contact area is formed by a continuous, interrupted, or partially interrupted strip parallel to one or both opening edges of the hollow cylinder of the insulator. This support structure contact area achieves electrical contact between the first conductive field probe layer and the support structure. Particularly preferred is that the support structure contact area, constructed as a strip, has a width of 0.2 mm to 5.0 mm, more preferably 0.3 mm to 2 mm, and particularly preferably 0.5 mm to 1 mm.

[0032] Preferably, both the first and second contact devices are arranged on the second side of the hollow cylinder of the insulator, wherein the conductive connection between the first conductive field probe layer and the contact devices is guided through a through-hole in the insulator. This arrangement allows for simplified contact, particularly through the outer surface of the hollow cylinder of the field probe assembly. The connecting wires on the outer surface of the hollow cylinder of the field probe assembly do not affect the electric field between the dominant conductor, i.e., the primary conductor, and the second (especially internal) conductive field probe layer, which is under voltage, particularly medium or high voltage.

[0033] Preferably, the first and second contact devices are each configured as pads. This design allows for the automatic establishment of simple contacts, especially contacts with electrical wires.

[0034] Particularly preferred are the first and second contact devices, which are respectively constructed as gold-plated or silver-plated disks. This design allows for simple contact, especially with connection elements used for grounding and signal forwarding.

[0035] Particularly preferred is that the contact device is connected to an additional circuit board, which replaces the electrical wires to achieve contact for the field probe assembly. Particularly preferred is that this additional circuit board is flexible, i.e., reversibly bendable. Even more preferred is that the plug or socket for contacting the field probe assembly is arranged on the additional circuit board or another flexible circuit board.

[0036] Further preferably, the insulator has an insulator thickness between 0.001 mm and 0.15 mm, particularly preferably between 0.04 mm and 0.08 mm, and a dielectric strength of 10 V / μm to 7 kV / μm, particularly preferably between 10 V / μm to 250 V / μm or 150 V / μm to 7 kV / μm, perpendicular to the axis of symmetry, i.e., in the radial direction of the hollow cylinder of the field probe assembly.

[0037] Particularly preferred is that the insulator has an insulator thickness of 0.05 mm ± 0.005 mm and a dielectric strength of 250 V / μm ± 5 V / μm in the radial direction of the hollow cylindrical shape of the field probe assembly, perpendicular to the axis of symmetry. In achieving such a small insulator thickness, especially in small installation spaces, a high degree of uniformity in the insulator thickness is required.

[0038] Preferably, the field probe assembly is formed of a PCB or circuit board partially coated with copper on both sides, particularly a PCB or circuit board partially coated with copper on both sides and of a flexible construction. Such a double-coated PCB exhibits high uniformity in the thickness of each layer and is therefore particularly well-suited. Within the scope of this disclosure, flexibility should be understood as the ability of the circuit board to be reversibly bent, i.e., not damaged during bending.

[0039] It is also preferred that the insulator is formed of pre-impregnated fibers, especially FR4 material.

[0040] It is also preferred that the insulator is formed of a polyimide film.

[0041] Preferably, the first conductive field probe layer and the second conductive field probe layer are formed of copper, wherein the first conductive field probe layer and the second conductive field probe layer have thicknesses between 0.017 mm and 0.105 mm, respectively, in the radial direction of the hollow cylinder of the insulator.

[0042] Particularly preferred is that the first conductive field probe layer and the second conductive field probe layer are formed of copper layers, wherein the first conductive field probe layer and the second conductive field probe layer have a thickness of 0.025 mm to 0.045 mm in the radial direction of the hollow cylinder of the insulator, and particularly have a thickness of 0.035 mm ± 0.005 mm in the radial direction of the hollow cylinder of the insulator.

[0043] This flexible PCB, with an insulation thickness of 0.05mm ± 0.005mm and a dielectric strength of 250V / μm ± 5V / μm, and a copper layer thickness of 0.035mm ± 0.005mm, enables a field probe assembly that is particularly smaller in size. This field probe assembly is suitable for medium-voltage equipment with a rated voltage of 40.5kV and a maximum lightning impulse voltage of 200kV, and is also suitable for a rated current of 1250A.

[0044] This PCB is not only surprisingly well-suited to prevent flashover and breakdown through the insulator between the first and second conductive field probe layers even under a 200kV lightning impulse voltage on the primary conductor, but it also achieves a compact structure that allows for a smaller bushing than in conventional cases.

[0045] Preferably, the field probe assembly has one or more recesses and / or openings / grooves parallel to the axis of symmetry of the hollow cylinder of the field probe assembly. The openings and / or grooves are arranged such that tabs are respectively retained at the edges of the hollow cylinder and sufficient insulation between the first conductive field probe layer and the second conductive field probe layer is ensured.

[0046] The recesses or gaps allow the casting resin to flow better around the field probe assembly and thus improve the pouring into the sleeve when the field probe assembly is subsequently cast with casting resin. Additionally, the recesses or gaps facilitate molding, particularly by bending a planar basic shape into a hollow cylinder or a hollow cylinder with openings.

[0047] It is also preferred that the surfaces of the field probe assembly, particularly the surfaces of the first conductive field probe layer and the second conductive field probe layer, be surface-treated in such a way that the surfaces have increased roughness compared to the case without such surface treatment.

[0048] This increased roughness results in better adhesion of the casting resin, which allows the field probe assembly to be cast in a more advantageous manner or the field probe assembly to be cast in a more advantageous manner.

[0049] Particularly preferred is the application of a multi-bonded coating, i.e., a coating that improves adhesion properties, especially the adhesion of plastics such as casting resins.

[0050] It is particularly preferred that the first conductive field probe layer and the second conductive field probe layer are made of copper or formed of copper, and the surface treatment includes at least forming cuprous oxide (I) and / or copper oxide (II) on the surfaces of the first conductive field probe layer and the second conductive field probe layer.

[0051] Preferably, the field probe assembly further includes at least one or more temperature sensors, wherein the one or more temperature sensors measure the temperature of the field probe assembly, or the temperature of the field probe assembly can be measured in such a way that the temperature measurement value can be determined and the temperature measurement value can be used to correct the measured voltage with the aid of temperature compensation.

[0052] Particularly preferred is that one or more temperature sensors are formed using one or more pt100 or pt1000 SMD components.

[0053] Preferably, the temperature sensor can be contacted by one, two or more pads and / or has contact pins.

[0054] Another embodiment relates to a bushing for medium- and high-voltage switchgear, the bushing having one or more field probe combinations according to one or more of the above-described designs.

[0055] Particularly preferred is that one or more field probe assemblies are fixed within a sleeve by a plastic, particularly cast resin, surrounding a primary conductor. For this purpose, the field probe assemblies are arranged around the primary conductor such that the primary conductor is positioned on or parallel to the axis of symmetry of the hollow cylindrical shape of the field probe assembly. The arrangement is then, if necessary, cast with plastic, particularly cast resin, using other components such as supply lines, seals, flanges, and similar parts.

[0056] Preferably, two or more field probes are arranged sequentially within the casing. This arrangement provides enhanced fault protection through redundant design or two or more independent measurement systems.

[0057] Preferably, the bushing has one or more temperature sensors, which are particularly compatible with a measuring device for determining the applied voltage, thereby determining the temperature of the bushing and using temperature compensation to correct the measured voltage value. Particularly preferred is that one or more temperature sensors are arranged on the field probe assembly and thus measure the temperature of the field probe assembly and therefore the temperature of the bushing at the field probe assembly. Alternatively, it is preferred that one or more temperature sensors are arranged spatially close to or on the field probe assembly, and thus determine the temperature of the bushing at the field probe assembly. "Spatially close" here should mean a distance between 0.2 mm and 5 mm from the field probe assembly.

[0058] Particularly preferred is that one or more temperature sensors are formed from one or more pt100 or pt1000 SMD components.

[0059] Another embodiment relates to a switchgear for medium- and high-voltage switchgear, the switchgear having one or more bushings according to one or more of the above-described technical solutions. The bushing has one or more field probe combinations according to one or more of the above-described technical solutions.

[0060] Preferably, at least one bushing has one or more temperature sensors that, in order to determine the applied voltage, can be connected to or to a measuring device, such as a measuring device of a switching device, so that the temperature of the bushing can be determined and therefore the temperature of the field probe assembly can be determined, and the temperature of the bushing can be used to correct the measured voltage using temperature compensation. Particularly preferred is that one or more temperature sensors are arranged on the field probe assembly and thus measure the temperature of the field probe assembly and therefore the temperature of the bushing at the field probe assembly.

[0061] Particularly preferred is that one or more temperature sensors are formed from one or more pt100 or pt1000 SMD components.

[0062] Another embodiment relates to a method for manufacturing a sleeve according to one or more of the above-described technical solutions, the sleeve having a field probe assembly according to one or more of the above-described technical solutions, wherein...

[0063] - At least a field probe assembly and a primary conductor are positioned in a casting mold or injection mold, the field probe assembly having a first contact device and a second contact device.

[0064] - The field probe assembly has the shape of a hollow cylinder.

[0065] -In this configuration, the primary conductor is arranged along the longitudinal axis of the hollow cylinder, and

[0066] - At least partially cast or encapsulate the field probe assembly and the primary conductor with electrically insulating plastic such that the area between the field probe assembly and the primary conductor is filled with electrically insulating plastic.

[0067] The above design schemes can be combined in various ways, as long as they are not replacements. Attached Figure Description

[0068] The solutions and designs are described in more detail below with reference to the accompanying drawings, wherein possible designs are not limited to the features described in the drawings.

[0069] Figure 1 A schematic diagram of the switching device is shown;

[0070] Figure 2 A schematic longitudinal section is shown, obtained by cutting through a sleeve with a field probe assembly according to the invention;

[0071] Figure 3 A schematic cross-sectional view of the field probe assembly according to the invention in insulating plastic is shown;

[0072] Figure 4 A schematic diagram of a field probe assembly according to the invention in an insulating plastic having a primary conductor is shown;

[0073] Figure 5 An equivalent circuit diagram of the field probe assembly according to the present invention is shown. Detailed Implementation

[0074] Figure 1 A schematic diagram of a switching device 1 is shown, which has an indicating instrument 4 and an operation panel 6 for operating the switching device 1. The operation panel 6 may be virtual, for example, in the form of a touch screen, or designed as a mechanical and / or electrical switching element. The indicating instrument 4 is designed as an analog or digital indicating instrument. The corresponding indicating instrument 4 displays, for example, gas pressure, voltage, current, switch status, temperature, or switch status.

[0075] Figure 2 A schematic longitudinal section is shown, obtained by cutting through a sleeve 10 according to the invention, which has a field probe assembly 100 according to the invention. The sleeve 10 has a primary conductor 20 extending along the longitudinal axis 35 of the sleeve 10. In a preferred embodiment, the primary conductor 20 has a constriction 22 in a region of the field probe assembly 100.

[0076] Arranged around the primary conductor 20 is a field probe assembly 100, which is optionally connected to a bushing connection flange 12. Optionally, the bushing connection flange 12 is electrically connected to a second field probe 112 (not shown). The primary conductor 20, the field probe assembly 100, and the bushing connection flange 12 are partially cast with electrically insulating plastic 30, particularly casting resin 30. Here, the end of the primary conductor 20 located on the longitudinal axis 35 is not covered by the electrically insulating plastic 30. A portion of the optional bushing connection flange 12 is also not covered by the electrically insulating plastic 30 to allow for soldering. Furthermore, the area surrounding the field probe assembly 100 is not covered by the electrically insulating plastic 30 to allow for conductive connection to connecting wires 14, 16, 18 and / or temperature sensor 130 of contact devices 121, 123 (not shown). Optionally, the connecting wires 14, 16, 18 are designed here as conductive metal pins so that a plug can be accommodated in a socket formed by the connecting wires 14, 16, 18 and the electrically insulating plastic 30. In another alternative design, the optional sleeve connection flange 12 can support the optional support structure 118 (not shown here) (see Figure 4 () function.

[0077] Figure 3 A schematic cross-sectional view of the field probe assembly 100 according to the invention in insulating plastic 30 is shown. A primary conductor 20 extending along the longitudinal axis 35 is centrally arranged in the plastic 30 and the field probe assembly 100.

[0078] The field probe assembly 100 is formed, for example, using an insulator 111, such as a flexible insulator 111, on which a first conductive field probe layer 120, serving as a first field probe 110 (not shown), and a second conductive field probe layer 122, serving as a second field probe 112 (not shown), are arranged. The insulator 111 has a hollow cylindrical shape, and the first conductive field probe layer 120 is arranged on the inner side of the hollow cylinder facing the longitudinal axis 35. The inner side of the hollow cylinder is also referred to as the inwardly pointing first side 116 of the hollow cylinder of the insulator 111. The second conductive field probe layer 122 is arranged on the outer side of the hollow cylinder of the insulator 111, which is opposite to the longitudinal axis 35. The outer side of the hollow cylinder is also referred to as the outwardly pointing second side 117 of the hollow cylinder of the insulator 111.

[0079] In the preferred design shown here, the second contact device 123 is disposed at the second conductive field probe layer 122 and can make conductive contact through a recess in the insulating plastic 30. Furthermore, in an advantageous design, a conductive channel 125, i.e., a plated through-hole or vertical interconnect access (VIA), is provided in the insulator 111. The first contact device 121 is electrically connected to the first conductive field probe layer 120 via this conductive channel 125 and is disposed electrically insulated from the second conductive field probe layer 122 on the outside of the insulator 111. With this arrangement, both the first contact device 121 and the second contact device 123 are conductively connected from the outside of the field probe assembly 100 through a recess in the insulating plastic 30. Alternatively, as an alternative to wires, one or more additional flexible circuit boards are led out from the first contact device 121 and the second contact device 123; these flexible circuit boards preferably have their own sockets or plugs. The one or more additional flexible circuit boards can be electrically connected to the first contact device 121 and the second contact device 123 respectively by pressing, bonding, welding, tightening, clamping or other fastening measures.

[0080] Further advantageously, the field probe assembly 100 is provided with a temperature sensor 130, or at least one temperature sensor 130 is arranged spatially close to the field probe assembly 100, for example, at a distance between 0.2 mm and 5 mm, or arranged on the field probe assembly 100. In the example shown, the temperature sensor 130 is arranged on an insulator 111, and a recess in the electrically insulating plastic 30 allows contact (or contact connection) of the temperature sensor 130 from the outside of the field probe assembly 100. In an example not shown, the temperature sensor 130 is arranged such that it can be contacted via the same recess in the electrically insulating plastic 30 as the first contact device 121 and the second contact device 123. This arrangement in Figure 2 The description is as follows. Insulator 111 has an insulator thickness 115, which is preferably between 0.001 mm and 0.15 mm, and particularly preferably 0.05 mm. Insulator 111 preferably has a dielectric strength of 10 V / μm to 7 kV / μm, and particularly preferably 250 V / μm ± 5 V / μm.

[0081] In another example, not shown, the temperature sensor 130 is designed as an SMD temperature sensor and is fastened to one, two, or more pads on the insulator 111 and makes contact through said pads. A wire is then guided outward, preferably through an additional contact device, more preferably through another contact device spatially close to the first and / or second contact device at a distance of 0.5 mm to 15.0 mm.

[0082] The total thickness 119 of the first conductive field probe layer 120, the second conductive field probe layer 122, and the insulator 115 is preferably 0.09 mm to 0.17 mm, and particularly preferably 0.12 mm ± 0.005 mm.

[0083] The radial electric field 40 surrounding the primary conductor 20 is indicated by an arrow.

[0084] Figure 4 A schematic perspective view of a field probe assembly 100 according to the invention is shown in an insulating plastic 30 having a primary conductor 20. Recesses in the plastic, temperature sensors, contact devices, or connecting wires are not shown here.

[0085] The primary conductor 20 is centrally positioned within the field probe assembly 100, and both are enclosed by insulating plastic 30, see [reference]. Figure 2 The field probe assembly 100 may optionally have a support structure 118 that maintains the field probe assembly 100 as a hollow cylinder in addition to its inherent stability.

[0086] The field probe assembly 100 shown here has a continuous slot 132 within the hollow cylinder of the insulator 111. Additionally, an optional slot 135 exists within the field probe assembly 100, which facilitates casting of this arrangement. To prevent the risk of conductive bridging, leakage current, or flashover between the first conductive field probe layer 120 and the second conductive field probe layer 122, the slot in the insulator 111 is optionally smaller in area than the slots in the first and second conductive field probe layers 120, such that the insulator 111 extends into the slot.

[0087] Figure 5 An equivalent circuit diagram of a field probe assembly 100 according to the invention, housed in a sleeve 10 (not shown), is shown. The field probe assembly 100 has a first field probe 110, which is arranged insulated surrounding a primary conductor 20. Insulation is achieved by using electrically insulating plastic 30 (not shown) to space and fill the intermediate space between the field probe assembly 100 and the primary conductor 20, wherein the insulating plastic 30 also at least partially surrounds the field probe assembly 100. The electrical insulation between the primary conductor 20 and the first field probe 110 defines a first capacitance C1. Source voltage U q or U p1 An application is made to the primary conductor. With a normal distance and insulating resin as the insulating plastic 30, the resulting first capacitance C1 is approximately 10 pF. The first field probe 110 and the second field probe 112 are separated from each other by an insulator 111 and together form a second capacitance C2. The second field probe 112 is grounded, thus obtaining a capacitive voltage divider consisting of C1 and C2.

[0088] Since the preferred insulator thickness 115 in the case of PI (polyimide) is 0.05mm ± 0.005mm, the capacitor C2 of approximately 2nF (2000pF) is intentionally significantly larger than the capacitor C1 of approximately 10pF. Capacitors C2 and C1 together form a capacitive voltage divider. Source voltage U q or U p1 Therefore, the voltage U is reduced to a lower level. m It can be tapped and / or measured at contact device 121.

[0089] Contact device 121 can be exposed via an optional recess in the insulating plastic 30. However, due to the preferred design of the field probe assembly 100, there will never be an unacceptable high voltage at contact device 121 that could be harmful to people, components, or equipment. Under rated operation with a rated voltage Up of approximately 40.5 kV, U is obtained. p2nenn (Voltage drop through capacitor C2 at rated voltage):

[0090]

[0091] Meanwhile, insulator 111 must not break down under the maximum lightning impulse voltage of 200kV (typically for 40.5kV medium-voltage switchgear).

[0092] Get U p2max (Voltage drop through capacitor C2 under maximum lightning impulse voltage):

[0093]

[0094] U p2max It must be less than the breakdown strength of insulator 111. Assuming, for example, the breakdown strength of PI or polyimide is 250 V / μm and the insulator thickness 115 is 0.05 mm, as required, UkV p2max The breakdown strength of the insulator is less than 12.5kV, which is 111.

[0095] also, Figure 5 It also shows a voltage drop U m The current I of surge arrester 140 and flow direction measuring device 145 Mess Both the measuring device 145 and the surge arrester 140 are grounded. The measuring device has an impedance Z. 测量设备 .

[0096] List of reference numerals

[0097] 1. Switchgear;

[0098] 4. Indicating instruments of switchgear 1;

[0099] 6. Operation panel of switchgear 1;

[0100] 10 Bushings for switchgear 1;

[0101] 12 sleeve connection flanges;

[0102] 14. First thermocouple connecting wire;

[0103] 16. Second thermocouple connection wire;

[0104] 18 Connecting wires for the first conductive field probe layer of the first field probe 110

[0105] 20 primary conductor of sleeve 10;

[0106] The contraction section of the primary conductor 20 of sleeve 10;

[0107] 30. Plastics, especially casting resins;

[0108] 35. Longitudinal axis of sleeve 10;

[0109] 40. Electric field surrounding primary conductor 10;

[0110] 100-field probe combination;

[0111] The first probe in a combination of 110 probes and 100 probes;

[0112] 111 Insulator;

[0113] The second probe in the 112-field probe combination of 100;

[0114] The insulation thickness of 115 insulator and 111 insulator;

[0115] The first inward-pointing side of the hollow cylinder of insulator 116;

[0116] The second outward-pointing side of the hollow cylinder of insulator 117;

[0117] 118 support structure;

[0118] 119 The total thickness of the first and second conductive field probe layers and the insulator;

[0119] 120 is used for the first conductive field probe layer of the first field probe 110;

[0120] 121 First contact device;

[0121] 122 is used for the second conductive field probe layer of the second field probe 112;

[0122] 123 Second contact device;

[0123] 125 is a conductive channel passing through insulator 111;

[0124] 130 temperature sensor

[0125] Continuous gaps in the hollow cylinder of insulator 132 111

[0126] The gap in the 135 field probe combination 100

[0127] 140 surge arrester

[0128] 145 Measuring Equipment

Claims

1. A field probe assembly (100) for use in medium and high pressure applications, the field probe assembly having a first field probe (110) and a second field probe (112). wherein The first field probe (110) and the second field probe (112) are formed by a first conductive field probe layer (120) applied to an insulator (111) for the first field probe (110) and by a second conductive field probe layer (122) applied to the insulator (111) for the second field probe (112). Wherein, the insulator (111) has The shape of a hollow cylinder, or The shape of the hollow cylinder with a slit opened parallel to the axis of symmetry of the field probe assembly (100) The insulator (111) has an insulator thickness (115) perpendicular to the axis of symmetry, i.e., in the radial direction, which separates the first conductive field probe layer (120) from the second conductive field probe layer (122). The first conductive field probe layer (120) is disposed on the first side (116) of the insulator (111), the first side pointing radially toward the interior of the hollow cylinder, and the second conductive field probe layer (122) is disposed on the second side (117) of the insulator (111), the second side pointing radially outward on the hollow cylinder. The first conductive field probe layer (120) has a first contact device (121) and the second conductive field probe layer (122) has a second contact device (123). A support structure (118) is applied to the insulator (111) to support the field probe assembly (100) in a manner that preserves the hollow cylindrical shape. Its features are, The support structure (118) is formed of conductive plastic and is arranged circumferentially at the opening edge of the hollow column of the insulator (111).

2. The field probe assembly (100) according to claim 1. Its features are, The first contact device (121) and the second contact device (123) are both arranged on the second side (117) of the hollow column of the insulator (111). The conductive connection between the first conductive field probe layer (120) and the first contact device (121) is guided through a through hole in the insulator (111).

3. The field probe assembly (100) according to claim 1. Its features are, The first contact device (121) and the second contact device (123) are respectively configured as pads.

4. The field probe assembly (100) according to claim 1. Its features are, The insulator (111) has an insulator thickness (115) between 0.04 mm and 0.08 mm in the radial direction perpendicular to the axis of symmetry and has a dielectric strength between 10 V / μm and 30 V / μm.

5. The field probe assembly (100) according to claim 1. Its features are, The field probe assembly (100) is formed of a PCB with copper coating on both sides.

6. The field probe assembly (100) according to claim 1. Its features are, The insulator (111) is formed from pre-impregnated fibers or polyimide film.

7. The field probe assembly (100) according to claim 1. Its features are, The first conductive field probe layer (120) and the second conductive field probe layer (122) are formed of copper, wherein the first conductive field probe layer (120) and the second conductive field probe layer (122) have thicknesses between 0.02 mm and 0.05 mm, respectively, in the radial direction of the hollow cylinder of the insulator (111).

8. The field probe assembly (100) according to claim 1. Its features are, The field probe assembly (100) has one or more recesses or slits parallel to the axis of symmetry of the hollow cylinder of the field probe assembly (100), the slits being arranged such that tabs are respectively retained at the edges of the hollow cylinder.

9. The field probe assembly (100) according to claim 1. Its features are, The surfaces of the first conductive field probe layer (120) and the second conductive field probe layer (122) are surface treated to give the surfaces an increased roughness compared to the surface without the surface treatment.

10. The field probe assembly (100) according to claim 9. Its features are, The first conductive field probe layer (120) and the second conductive field probe layer (122) are made of copper or formed of copper, and The surface treatment includes at least forming cuprous oxide (I) and / or copper oxide (II) on the surfaces of the first conductive field probe layer (120) and the second conductive field probe layer (122).

11. The field probe assembly (100) according to claim 1. Its features are, The field probe assembly (100) further includes at least one temperature sensor (130), wherein the temperature sensor (130) measures the temperature of the field probe assembly (100) and is thus able to determine a temperature measurement value, and the temperature measurement value can be used to correct the measured voltage with the aid of temperature compensation.

12. A bushing (10) for medium-voltage and high-voltage switchgear, the bushing having one or more field probe combinations (100) according to any one of claims 1 to 11.

13. A switchgear (1) for medium-voltage and high-voltage switchgear, the switchgear having one or more bushings (10) according to claim 12.

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