High-voltage device and method for checking a high-voltage device

Abstract

A high voltage device (1), preferably for use as a cable termination, and a method for testing a high voltage device (1). The high voltage device (1) has: an insulation body (20); an inner conductor (10) guided through the insulation body (20) in an axial direction; wherein the insulation body (20) comprises a plurality of control inserts (22a to 22g) for field control arranged concentrically around the inner conductor (10), the control inserts being preferably made of a conductive foil; and the insulation body (20) forms an inner cone (21) at one axial end.

Description

Technical Field

[0001] This application relates to a high-voltage device, preferably used as a cable terminal, and a method for inspecting the high-voltage device. Background Technology

[0002] At the end of a solid-insulated high-voltage cable, a cable termination is required to transition to an overhead line or switchgear. The cable termination forms a mechanical connection with the cable and also facilitates the electrical and field technology adaptation to the cable.

[0003] Field distribution is typically controlled by a few large electrodes at ground potential and high voltage potential, which can extend to the surface of the insulator. Newer developments focus on using numerous conductive inserts, also known as "control inserts," for finer control at the cable termination side. These inserts allow for intermediate potentials and thus achieve uniform field load.

[0004] EP 4 243 229 A1 describes a high-voltage device that can be used as a cable termination, having an insulator, an inner conductor, and a plurality of control inserts for field control arranged concentrically around the inner conductor.

[0005] Thin control inserts must not extend to the surface of the insulator, as this could result in excessively high electric field strength. The challenge lies in optimally determining the location of the control inserts and ensuring, through a precisely defined manufacturing process, that the position of the control inserts in the finished product corresponds to the design specifications. Summary of the Invention

[0006] The objective of this invention is to provide an improved high-voltage device and an improved method for inspecting the high-voltage device.

[0007] This task is solved by a high-voltage device having the features of claim 1 and a method having the features of the parallel method claims.

[0008] Advantageous improvements are derived from the dependent claims, the following presentation of the invention, and the description of preferred embodiments.

[0009] The present invention relates to a high-voltage device, which is preferably used as a cable terminator, for example for connecting cables to lines, especially overhead lines.

[0010] A high-voltage device includes an insulator and an inner conductor that is guided axially through the insulator. In other words, the insulator surrounds the inner conductor. The inner conductor defines both the axial and radial directions. The high-voltage device is preferably configured to be axisymmetric.

[0011] Multiple control inserts for field control are arranged concentrically around the inner conductor within the insulator. These control inserts are preferably made of conductive foil. The control inserts preferably extend entirely within the insulator; that is, the control inserts, especially their ends, should not protrude from the surface of the insulator, otherwise they would cause high electric field strength.

[0012] The insulator is constructed as an inner cone at its axial end. The control insert extends into the inner cone with its axial end, thereby enabling fine field control in that region.

[0013] The high-voltage device according to the invention has the basic function of a capacitor-controlled high-voltage pass-through having a receiving portion for a cable end in the form of an inner cone. Through its precise axial and radial control of the electric field, the high-voltage device achieves a very uniform and low load on the surrounding insulating medium (e.g., free air, oil, gas, solid) while maintaining a compact overall size. The high-voltage device provides a resource-saving and cost-effective implementation of a dry, e.g., resin-impregnated, capacitor-controlled high-voltage pass-through. Optimal field technology design can keep the load on the component's electric field strength as low as possible.

[0014] The axial distance between the axial ends of the shortest and longest control inserts is called the axial control path. When the axial ends of the inner control inserts define an imaginary control line, the region along the insert ends from the beginning to the end of the imaginary line is called the control path. Longer control paths generally allow for more effective field control.

[0015] Preferably, the control insert placed radially closest to the inner conductor has the smallest distance from the outer surface of the inner cone compared to the other control inserts. The control insert closest to the inner conductor at the high-voltage potential, also referred to herein as the "high-voltage insert," defines the position where control begins and is preferably positioned such that there is the smallest possible distance from the insulating surface (outer surface) of the inner cone. This achieves maximum shielding of the areas below the high-voltage insert, which may contain sharp metal parts or air gaps.

[0016] For the same reason, the high-pressure insert preferably extends beyond the beginning of the cone, that is, in this case, the high-pressure insert extends axially beyond the beginning of the inner cone.

[0017] Preferably, the control insert comprises a set of internal control inserts, wherein, viewed in the radial direction, the distance between the axial end of the internal control insert and the outer surface of the inner cone increases from the inside to the outside. In this way, the potential attenuation in both the axial and radial directions is optimized.

[0018] When the axial end of the internal control insert defines an imaginary control line, the control line and the inner cone line preferably form a control angle α greater than 0 (α > 0), the inner cone line being defined by the outer surface of the inner cone in the longitudinal section.

[0019] The length of the control path and / or the control angle, along with the number of control inserts, are selected based on the operating and test voltage values ​​to ensure that potential attenuation in the axial and radial directions results in the lowest possible field load. The corresponding electrode geometry and position on the sides of the cable connector are also considered in the design and can lead to individual fits.

[0020] Preferably, when viewed in the radial direction, the insulator has a hollow cylindrical section adjacent to the inner cone, which extends the insulator axially relative to the axial end of the inner cone. Thus, the hollow cylindrical section protrudes outward, for example, toward the cable connector to be connected.

[0021] Preferably, the control insert, which is the last control insert provided radially as an insulator, extends axially into the aforementioned section. The control insert extending into the aforementioned section is located at ground potential.

[0022] By extending the final control insert in this way, especially beyond the control path, the field load is confined to the area below the control insert between the high-voltage device and the connector. This has the advantage of creating a shielded transition zone and eliminating significant field loads outside the connection area.

[0023] Preferably, the insulator comprises a cured resin, for example, in the form of a resin-impregnated insulating layer. Such an insulator, after impregnation with a resin (e.g., epoxy resin), is shape-stable and forms a relatively rigid mass. The insulating layer may comprise paper or nonwoven fabric and is concentrically or helically wound around the inner conductor to form a winding body. In this way, the manufacture of the high-voltage pass-through can be particularly simple and cost-effective. Furthermore, a particularly uniform arrangement of the insulating layer within the insulator can be ensured. The high-voltage device designed in this way is particularly maintenance-free.

[0024] The aforementioned task is also addressed by a method for inspecting a high-voltage device. This method includes: manufacturing a high-voltage device comprising an insulator and an inner conductor, the inner conductor being guided axially through the insulator, wherein a plurality of control inserts for field control are disposed within the insulator and arranged concentrically around the inner conductor; and inspecting the position of at least one of the control inserts by ultrasonic measurement, the ultrasonic measurement being performed using an inspection device equipped with an ultrasonic sensor.

[0025] Ultrasonic inspection allows for quality assurance and / or inferring potential positional variations during manufacturing of high-voltage units and / or creating control insert profiles to demonstrate proper function. Ultrasonic inspection for reliably determining control insert location renders pre-inspection of high-voltage units with connected cables redundant. Individual post-manufacturing inspection of the high-voltage unit is sufficient for direct installation at the point of use.

[0026] Preferably, the inspection device is based on the measurement principle of pulse echo method and / or transmission method, thereby ensuring that the position determination of the control insert can be reliably performed.

[0027] Ultrasonic measurements can be performed using contact and / or immersion techniques.

[0028] To improve measurement accuracy, the inspection device is preferably adjusted to the sound velocity of one or more materials of the insulator before ultrasonic measurement.

[0029] Preferably, ultrasonic measurements are performed along the entire control path to ensure a comprehensive quality inspection of the high-voltage device.

[0030] This inspection method is not limited to insulators with inner cones, but is equally applicable to insulators of other geometries, especially insulators with outer cones.

[0031] When examining a high-voltage device according to one of the above-described embodiments, the features, technical effects, advantages, and embodiments described regarding the high-voltage device are similarly applicable to this method.

[0032] Further advantages and features of the present invention will become apparent from the following description of preferred embodiments. The described features may be implemented individually or in combination with one or more of the above features, provided that these features do not contradict each other. The following description of preferred embodiments is given herein with reference to the accompanying drawings. Attached Figure Description

[0033] Preferred embodiments of the invention are illustrated in more detail below with reference to the figures. Herein lies: Figure 1 A longitudinal section of a high-voltage device having an inner conductor, an insulator, and multiple control inserts arranged therein is schematically shown. Detailed Implementation

[0034] The following will use Figure 1 Preferred embodiments are described.

[0035] Figure 1 A longitudinal section of a high-voltage device 1, having an inner conductor 10 and an insulator 20 surrounding the inner conductor 10, is schematically shown. The high-voltage device 1 is axisymmetrically constructed, wherein... Figure 1 Only half of the insulator 20 is shown. The high-voltage device 1 can be used as a cable termination for a high-voltage cable.

[0036] Insulator 20 includes an inner cone 21, which is configured to receive a cable connector (in Figure 1 (not shown in the image) or complementary ends of similar objects. The inner cone 21 is defined by an outer surface 21a, the longitudinal section of which defines the inner cone line.

[0037] Inside the insulator 20, control inserts 22a to 22g extend concentrically around the inner conductor 10. The control inserts 22a to 22g extend with their axial ends into the inner cone 21 and enable fine field control in this region. The control inserts 22a to 22g are preferably made of conductive foil.

[0038] Preferably, the insulator 20 comprises a cured resin. According to an embodiment of the invention, the insulator 20 comprises a resin-impregnated insulating layer. Such an insulator 20, after impregnation with resin (e.g., epoxy resin), is shape-stable and forms a relatively rigid mass. The insulating layer may comprise paper or nonwoven fabric and is wound concentrically or helically around the inner conductor 10 to construct a winding body. In this way, the manufacture of the high-voltage pass-through 1 can be particularly simple and cost-effective. Furthermore, a particularly uniform arrangement of the insulating layer within the insulator 20 can be ensured. The high-voltage device 1 thus designed is particularly maintenance-free.

[0039] exist Figure 1 In this drawing, although control insert 22g is shown as the shortest control insert and 22a as the longest control insert, it is possible that control inserts 22a to 22g extend further to the left and are also hierarchical there, such that control insert 22b could be the shortest in the complete drawing, for example. In this specification, the terms "shortest," "longest," etc., are used in the context of control inserts. Figure 1 The illustration.

[0040] The axial distance between the axial end of the shortest control insert 22g and the axial end of the longest control insert 22a is called the axial control path S. As long as... Figure 1 In the embodiment where the axial ends of the internal control inserts 22b to 22g define an imaginary control line 24, the region along the ends of the inserts from the beginning to the end of the imaginary line 24 is referred to as the control path S. A longer control path S typically allows for more effective field control.

[0041] The control insert 22g closest to the inner conductor 10 (adjacent to it) at the high-voltage potential, also referred to herein as the "high-voltage insert," defines the position where control begins and is positioned such that there is the smallest possible distance a from the insulating surface of the inner cone 21. minThis achieves maximum shielding of the area below the high-voltage insert 22g, which may contain sharp metal parts or air gaps.

[0042] Preferably, the high-pressure insert 22g extends beyond the beginning of the cone, that is, in this case, the high-pressure insert 22g extends axially beyond the beginning of the inner cone.

[0043] The ends of the control inserts 22a to 22g should not be exposed from the surface of the insulator 20, because otherwise these ends would cause a high electric field.

[0044] According to this embodiment, the insulator 20 of the high-voltage device 1, in addition to the inner cone 21, has a protruding or hollow cylindrical section 23. This section has a hollow cylindrical shape and extends the insulator outward, i.e., toward the cable connector or the like. A control insert 22a, located therein and at ground potential, extends axially into the protruding section 23. This control insert is the last control insert of the insulator 20 in the radial direction. By extending beyond the control path S with such a last control insert 22a, the field load is limited to the area below the control insert 22a between the high-voltage device 1 (= high-voltage pass-through) and the plug or the like. This has the advantage of creating a shielded transition area and eliminating significant field load outside the insertion area.

[0045] The ends of the control inserts 22b to 22g in the inner cone 21, also referred to herein as "internal control inserts" (all control inserts excluding the outermost radially grounded control insert 22a), define an imaginary control line 24. This imaginary control line forms a control angle α (α > 0) greater than 0 with the outer surface 21a (= the inner cone line in the longitudinal section). In other words, the distance between the ends of the internal control inserts 22b to 22g and the outer surface 21a, i.e., the insulator surface, increases radially from the inside out.

[0046] The length of the control path S and / or the control angle α, along with the number of control inserts 22a to 22g, are selected based on the operating and test voltage values ​​to ensure that potential attenuation in the axial and radial directions results in the lowest possible field strength load. The corresponding electrode geometry and position on the sides of the cable connector are also considered in the design and can lead to individual fits. The permissible field strength is application- and material-dependent.

[0047] The field distribution influenced by the control inserts 22a to 22g varies depending on whether an AC voltage or a DC voltage is applied.

[0048] In order to determine the position of the control inserts 22a to 22g in the manufacturing process of the insulator 20, such as the winding process, the thermal shrinkage and expansion effects during the manufacturing process are preferably taken into account.

[0049] The aforementioned high-voltage device 1 provides a particularly compact, lightweight, and therefore resource-saving and cost-effective implementation of a dry (e.g., resin-impregnated and capacitor-controlled) high-voltage pass-through, especially as a cable termination. Optimal field technology design allows the load on the component's field strength to be kept as low as possible.

[0050] The inspection of the position of the inserts 22a to 22g, especially their end positions, along the surface of the completed insulator 20 is carried out by means of an inspection device 50, which includes an ultrasonic sensor 51.

[0051] The function of the inspection device 50 can be based on different measurement principles, including, for example, pulse-echo and / or transmission methods with one or more, especially two, ultrasonic sensors 51 arranged at an angle. The inspection can be performed not only by contact techniques but also by immersion techniques, wherein the ultrasonic sensors 51 can be moved manually or automatically.

[0052] Preferably, prior to ultrasonic measurement, the inspection device 50 is adjusted to the sound velocity of one or more materials of the insulator 20. The use of an intermediate element is also possible, which allows for full or partial angular compensation of the conical ramp. Measurements can be performed along the entire control path S, where checking the positions of some critical control inserts 22a to 22g as routine checks is also sufficient. This check can be performed multiple times at circumferentially offset positions.

[0053] The radial (depth) and axial positions of control inserts 22a to 22g or their ends can be definitively determined by calculating and evaluating the propagation time of the ultrasonic signal, taking into account the position of the ultrasonic sensor during measurement data acquisition (manually or automatically). Preferably, the calculation and evaluation are carried out by means of an evaluation device 52, which communicates with at least one ultrasonic sensor 51.

[0054] The above inspection scheme allows for quality assurance during the production of the high-voltage device 1, inferring any positional variations during the manufacturing process and / or creating control insert profiles to demonstrate proper function. This inspection scheme is not limited to the insulator 20 with the inner cone 21 as shown in the above figures, but is equally applicable to insulators of other geometries, particularly insulators 20 with an outer cone.

[0055] The reliably determined position of the control insert using the above-described inspection method makes pre-inspection of the high-voltage device 1 with connected cables unnecessary. A separate post-manufacturing inspection of the high-voltage device 1 is sufficient for direct installation at the point of use.

[0056] Where applicable, all individual features shown in the embodiments may be combined and / or interchanged with each other without departing from the scope of the invention.

[0057] List of reference numerals

[0058] 1. High-voltage device

[0059] 10 Inner conductor

[0060] 20 Insulators

[0061] 21 inner cone

[0062] 21a Outer surface

[0063] 22a...22g Control inserts

[0064] 23 Hollow columnar section

[0065] 24 control lines

[0066] 50 Inspection device

[0067] 51 Ultrasonic Sensor

[0068] 52 Evaluation Devices

[0069] S control path

[0070] a min Minimum distance of high voltage insert

[0071] α is the control angle.

Claims

1. A high-voltage device (1), preferably used as a cable termination device, the high-voltage device having: Insulator (20); Inner conductor (10), which is guided axially through the insulator (20); wherein... The insulator (20) includes a plurality of control inserts (22a to 22g) for field control arranged concentrically around the inner conductor (10), the control inserts preferably being made of conductive foil; and The insulator (20) forms an inner cone (21) at one axial end.

2. The high-voltage device (1) according to claim 1, characterized in that, The control insert (22g) placed closest to the inner conductor (10) in the radial direction has the smallest distance from the outer surface (21a) of the inner cone (21) compared to the other control inserts (22a to 22f).

3. The high-voltage device (1) according to claim 2, characterized in that, The control inserts (22a to 22g) include a set of internal control inserts (22b to 22g), wherein, when viewed in the radial direction, the distance between the axial ends of the internal control inserts (22b to 22g) and the outer surface (21a) of the inner cone (21) increases from the inside to the outside.

4. The high-voltage device (1) according to claim 3, characterized in that, The axial ends of the internal control inserts (22b to 22g) define an imaginary control line (24), which forms a control angle α greater than 0 with the inner cone line, which is defined by the outer surface (21a) of the inner cone (21) in the longitudinal section.

5. The high-voltage device (1) according to any one of the preceding claims, characterized in that, The control insert (22g) placed radially closest to the inner conductor (10) extends axially beyond the beginning of the inner cone (21).

6. The high-voltage device (1) according to any one of the preceding claims, characterized in that, Viewed in the radial direction, the insulator (20) has a hollow cylindrical section (23) adjacent to the inner cone (21), the hollow cylindrical section extending the insulator (20) in the axial direction.

7. The high-voltage device (1) according to claim 6, characterized in that, The control insert (22a), which is the last control insert provided in the radial direction of the insulator (20), extends into the protruding section (23) in the axial direction.

8. The high-voltage device (1) according to any one of the preceding claims, characterized in that, The insulator (20) comprises a cured resin in the form of a resin-impregnated insulating layer, which is concentrically or helically wound around the inner conductor (10) to form a winding body, wherein the insulating layer preferably comprises paper or nonwoven fabric.

9. A method for inspecting a high-voltage device (1), wherein, The method includes: Manufacture a high-voltage device (1) comprising an insulator (20) and an inner conductor (10) guided axially through the insulator (20), wherein a plurality of control inserts (22a to 22g) for field control are disposed in the insulator (20) concentrically arranged around the inner conductor (10); and The position of at least one of the control inserts (22a to 22g) is checked by ultrasonic measurement, which is performed using an inspection device (50) with an ultrasonic sensor (51).

10. The method according to claim 9, characterized in that, The inspection device (50) is based on the measurement principle of pulse echo method and / or transmission method.

11. The method according to claim 9 or 10, characterized in that, The ultrasonic measurements are performed using contact and / or immersion techniques.

12. The method according to any one of claims 9 to 11, characterized in that, Prior to the ultrasonic measurement, the inspection device (50) is adjusted to the sound velocity of one or more materials of the insulator (20).

13. The method according to any one of claims 9 to 12, characterized in that, The ultrasonic measurement is performed along the entire control path (S), which is defined by the axial distance between the axial end of the shortest control insert (22g) and the axial end of the longest control insert (22a).

14. The method according to any one of claims 9 to 13, characterized in that, The insulator (20) of the high-voltage device (1) forms an inner cone (21) or an outer cone at one axial end.

15. The method according to claim 14, characterized in that, The high-voltage device (1) is the high-voltage device (1) according to any one of claims 2 to 7.

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