Plug-in device

Abstract

The invention relates to a plug-in device (10) for detachable insertion into a receiving device (12) for establishing an electrical connection between a high-voltage direct current cable (16) and a high-voltage operating device, comprising an insulating body (18) that at least partially surrounds the high-voltage direct current cable (16), wherein the insulating body (18) has an interface (42) along its outer surface and a field control element (20, 22) made of conductive material is provided at each end region of the interface (42), which defines the interface (42), and a plug-in connection device (14), wherein a field control element (20) associated with a free end face (28) of the insulating body (18) is laid flat on or rests on the free end face (28) of the insulating body (18) as an insert or attachment part (91) or is applied as a coating (88), and wherein the second field control element (22),which is arranged opposite one field control element (20) on the insulating body (18) and is designed as a coating (88) or is attached and / or incorporated as an insert or attachment part (90, 92).

Description

[0001] The invention relates to a plug-in device for detachable insertion into a receiving device, for establishing an electrical connection between a high-voltage direct current cable and a high-voltage operating device, wherein the high-voltage direct current cable is at least partially surrounded by an insulating body.

[0002] DE 10 2004 054 639 A1 discloses a cable connector of a plug connection device for medium and high voltage technology, wherein the cable connector has a connecting element that can be electrically connected to a conductor of a cable, and via which, when the cable connector is plugged together with a counterpart of the plug connection device, an electrical connection is established between the conductor and a contact element of the counterpart, and wherein the cable connector has an insulating element which has at least a section a conical surface for electrically tight contact with an associated surface of the counterpart in the plugged-in state and which has a first section in which the insulating element receives the cable to be connected, wherein in a further longitudinal direction the insulating element has a second section which forms the conical surface.In this way, a cable connector has been created that can be used for a wide range of different cross-sections and diameters of conductors, ensuring easy assembly and permanently reliable contact.

[0003] EP 3 108 551 B1 describes a cable termination device for HVDC GIS systems with various configurations. A partition made of electrically insulating material is positioned around the power cable. This divides the cable termination device into two chambers, which can be filled with different insulating materials. To terminate the power cable, a control element is positioned at the level of the outer conductive layer end, creating a circumferential material layer along the interface between the control element and the cable for nonlinear resistive field control.

[0004] Furthermore, it is known from EP 3 095 161 B1 that a high-voltage cable connector prevents damage to the high-voltage cable connector or the socket element when making the plug connection in an electrically sealed system by means of an applied protective element at the end of its contact system.

[0005] In DE 10 2018 218 879 A1 it is further stated that, in general, a high-voltage bushing has the function of isolating a high-voltage line with a current-carrying conductor, which is at high-voltage potential, from an environment that is essentially at earth potential, for example, a housing of the high-voltage system. For example, the housing of a transformer may have a terminal block into which a high-voltage bushing can be inserted to connect the transformer to a high-voltage network.

[0006] From DE 101 39 251 C1, a plug connection for a medium-voltage switchgear is known. A plug connection with a metallic terminal and a cable attached thereto can be connected to a contact piece on a switchgear panel wall. This plug connection comprises a sealing element that surrounds one end of the cable and the metallic terminal. The sealing element has a ring collar that can be positioned in the contact piece and a conductive coating that is present on the inside and outside of the sealing element.

[0007] From EP 0 825 682 A2, a contact connector part is known which is suitable for connecting high-voltage cables. This contact connector part comprises a contact pin with a contact surface having a silver-graphite composite coating. Furthermore, the contact pin includes a field control element provided in a silicone body that at least partially surrounds the contact pin.

[0008] Based on this state of the art, the invention aims to create a solution that is improved compared to the state of the art and is particularly suitable for direct current in the high-voltage range.

[0009] A plug-in device with the features of claim 1 solves such a problem.

[0010] By having an interface along the outside of the insulating body and a field control element made of conductive material arranged at each end of the interface, the local electric field strengths in adjacent further interface areas of the plug-in device and the receiving device, in particular air gaps, as well as charge activities at the interfaces between the air and the insulating material of at least one insulating body and a receiving device, can be reduced to a level sufficient to create a safe and reliable electrical connection of a high-voltage direct current cable with other high-voltage equipment, for example in the form of gas-insulated switchgear (GIS) or transformers.

[0011] The connector according to the invention relates in particular to an electrical connector element for cables in the high-voltage direct current (HVDC) transmission range, where the HVDC cables in question are primarily intended to be plastic-insulated. The electric field distribution under a direct current (DC) load is largely determined by the temperature- and field-strength-dependent volume resistance of the insulating materials. With unfavorable design and / or material pairing, field enhancements can occur in insulating materials with high volume resistance due to field displacement, and further field enhancements in insulating materials and at their interfaces are caused by existing space charge accumulations under direct current (DC) load.The plug-in device according to the invention makes it possible to homogenize the field distributions in the adjacent or neighboring interfaces, in particular existing air gaps, by means of the respective additional field control element, and at the same time to weaken the charge activities, in particular at existing interfaces of air / insulating material, in order to avoid unwanted flashovers or breakdowns under direct current (DC) load.

[0012] Preferably, the field control elements each have an outer circumferential surface that merges flush into the interface of the insulating body and each have a contact surface outside the interface that merges into or borders the outer circumferential surface.

[0013] In a preferred embodiment of the connector, the respective field control element is mounted onto and / or embedded in the insulating body, preferably in the form of a coating or as an insert or attachment, which is preferably prefabricated. It is further preferred that the respective insert or attachment is made of an elastically compliant, conductive elastomer, such as silicone rubber or ethylene propylene diene monomer (EPDM) rubber, preferably made of the same base material as the insulating body. The respective field control elements can thus be connected to the insulating body in a particularly assembly-friendly manner, forming a single unit.In particular, the respective insert or attachment can be placed flat on the insulating body, for example as part of a vulcanization process, and connected to it, or at least one external recess is created in the insulating body into which the insert or attachment is preferably inserted or fitted in such a way that the outer contour of the insulating body remains essentially undisturbed in its course.

[0014] Preferably, conductive dispersions or conductive paint can also be used for the coating, which is applied to the insulating body, preferably in a circumferential recess, either by spraying or by hand with a brush. The coating can be applied partially or largely over the entire surface of the insulating body's outer surface; however, it is more preferred that a corresponding recess or cavity is also provided in the insulating body for the coating, into which the respective coating is applied in such a way that the closed contour of the insulating body's outer surface remains undisturbed. In addition to conductive dispersions or conductive paint, other suitable coating materials can also be used if required.

[0015] It is further preferred that different types of field control elements, in the form of a coating or as an insert or attachment, are used simultaneously on an insulating body. It is also possible that the field control elements provided in the interface area on the outside are uniformly designed, so that, for example, both field control elements are formed from a coating or as an insert or attachment. Any combination of two field control elements is also possible. The respective field control element is preferably connected to the insulating body without an air gap in order to reduce the local electric field strengths in adjacent air gaps and to decrease the direct current (DC) load.

[0016] Preferably, the respective insert or attachment is designed as a closed ring body that encompasses the high-voltage direct current cable. If required, the ring body can also form a torus. In this radial direction, the insert or attachment thus encompasses the high-voltage direct current cable, which protrudes axially from both sides of the insert or attachment. Furthermore, the insert or attachment can be designed as a closed ring body in which an earth deflector is integrated. This facilitates simple manufacturing and assembly.

[0017] In the plug-in device according to the invention, one insert or attachment part rests flat against or on one end face, and the second insert or attachment part is inserted towards the other end face of the insulating body. The insulating body can have a truncated cone shape, which includes at least one bend line around its circumference. The bend line, arranged at a distance from the end face of the insulating body, separates the interface on the outside of the insulating body from further sections, such as a bending surface, of the truncated cone.

[0018] Furthermore, the field control element may be designed to have, in cross-section with respect to the longitudinal axis of the insulating body, an outer circumferential surface and a contact surface that are angled relative to each other, that transition into each other in an arc, or that are polygonal. The specific cross-sectional design of the field control element can be adapted depending on the application and design of the plug-in device.

[0019] In a preferred embodiment, a contact system is arranged adjacent to the insulating body and pointing in the insertion direction towards the receiving device. This contact system consists of at least a contact ring and a clamping cone, with a pressure piece arranged between the clamping cone and an end face of the insulating body. In particular, the pressure piece has a metallic energy storage element that holds the pressure piece in contact with the field control element to maintain an electrical connection. This allows the electrical connection to be maintained, especially under changing temperatures. The energy storage element can be a mechanical element, such as a spring or the like. The pressure piece can be metallic or insulating.

[0020] Advantageously, a pressure sleeve is provided, positioned opposite the insertion direction into the receiving device and resting against the insulating body. This pressure sleeve has a pressing surface that rests against the contact surface of the additional field control element. Furthermore, the pressure sleeve, with a force storage element, can press the insulating body into the receiving device via the contact surface of the additional field control element. This enables the necessary contact pressure between the interface of the insulating body and a contact surface of the socket of the receiving device, thereby increasing the electrical strength of the so-called high-grade joint.

[0021] The connector advantageously comprises an insulating sleeve extending from a flanged bell surrounding the high-voltage direct current cable towards the insulating body, with an end section of the insulating sleeve overlapping the contact surface of the additional field control element and only partially covering this contact surface. The metallic compression sleeve, which at least partially surrounds the insulating sleeve, rests against the uncovered portion of the contact surface of the field control element. This allows the field control element to make electrically conductive contact with the compression sleeve, which is grounded. Alternatively, the end section of the insulating sleeve can be positioned at a distance from the contact surface of the additional field control element, resting against a kinked surface of the insulating body.As a further alternative, the end section of the insulating sleeve, extending from the flange bell, can be configured to reach at least between the pressing surface of the pressure sleeve and the contact surface of the additional field control element, which is in the form of the insert or attachment component. This insert or attachment component comprises the outer circumferential surface, the contact surface, and the earth deflector as a single unit. The contact surface of the field control element is not completely overlapped by the end section of the insulating sleeve.

[0022] The invention further relates to a plug connection device with a plugging device as described above, wherein known applications for such devices are, for example, dry pluggable cable terminations for transformers and GIS switchgear, outdoor terminations and pluggable cable sleeves.

[0023] This connector has the advantage that the field control elements, arranged at the end of the insulating body's interface, minimize charge accumulation and the associated field increase in the adjacent interfaces, as these are dissipated via the field control elements and the attached pressure sleeve or pressure piece. Simultaneously, the field strength in the air gaps can be reduced.

[0024] Furthermore, it is preferably provided that a pressure sleeve on the plug connector, by means of a force storage element such as a spring assembly, presses the interface of the insulating body flat against the conical contact surface of a socket of the receiving device. This allows the necessary contact pressure to be applied so that virtually no air is present or an air gap is formed between them. Thus, partial discharge or flashover in this area can be prevented.

[0025] Preferably, at least one electrode is provided in the socket, wherein this electrode is assigned to and electrically connected to a contact socket of the receiving device. The outer circumferential surface of the field control element is positioned on the insulating body such that its outer circumferential surface does not exceed the height of the metallic electrode when inserted. The first electrode thus covers the outer circumferential surface of the field control element facing the contact socket. Furthermore, a second electrode may be provided in the socket, positioned at a distance from the first electrode and at ground potential. Again, the outer circumferential surface of this second field control element is not expected to exceed its height.

[0026] In the plug-in connection device, it is further preferably provided that a flange bell is arranged on the end face facing away from the insulating body, which comprises a flange part for establishing the flange connection with another flange part of the socket. This allows the plug-in device to be coupled and securely connected to the receiving device in a simple manner.

[0027] The following section explains the plugging device and the resulting plug connection system in more detail using exemplary embodiments shown in the drawing. The drawings are presented in a general, non-scale representation. Fig. 1 in the manner of a basic longitudinal section view, a plug-like plugging device together with a socket-like receiving device, which, shown separately from each other, form a plug connection device as a whole when connected, Fig. 2 a basic longitudinal section view of the plugging device and the receiving device in a connected state to form a plug connection device according to Fig. 1, Fig. 3 a basic longitudinal section view of an alternative embodiment of the plug connection device to Fig. 2, Fig. 4, Fig. 5 to Fig. 6. Partially, the upper half of each insulating body for the plug-in device according to the Fig. 1, with various types of field control elements both as an insert or attachment in the insulating body and as a coating and Fig. 7 a basic longitudinal section view of a further alternative embodiment of the plug connection device Fig. 2 with an insulating body of a plug-in device according to Fig. 6.

[0028] The Fig. Figure 1 shows, on the left side as viewed from the front, a plug-in device 10, which is designed for releasable insertion into a receiving device 12, as seen from the front. Fig. Figure 1 is shown on the right. The plug-in device 10, together with the receiving device 12, forms a plug-in connection device 14 as a whole, which, when plugged together, Fig. 2 is shown. This plug connection device 14 is used to establish an electrical connection between a high-voltage direct current cable 16 and parts of high-voltage equipment (not shown), such as a GIS switchgear or a transformer.

[0029] The excerpt in the Fig. The high-voltage direct current cable 16 shown is circumferentially enclosed by an insulating body 18 in the radial direction such that parts of the high-voltage direct current cable 16 project beyond the insulating body 18 on both sides when viewed axially. When the plug-in device 10 is inserted into the receiving device 12 in a contacting manner, forming the plug-in connection device 14, individual air gaps 100, 101 are created between the outside of the plug-in device 10 and the inside of the receiving device 12, so that the insulating body 18 at least partially limits and separates these air gaps from each other.

[0030] As the Fig. 1 and Fig. As further shown in Figure 2, the insulating body 18 has at least two field control elements 20, 22 made of conductive material such that the local electric field strengths in adjacent air gaps 100, 101 and charge activities at the interfaces between the air and the insulating material of the insulating body 18 and the receiving device 12 are reduced to a level that prevents the electrical strength of the air gaps, the insulating materials, and the interfaces from being exceeded. The field control elements 20, 22 are explained in more detail below.

[0031] The plug-in device 10 after the Fig. Figure 1 has the spindle-shaped insulating body 18, which is designed in the form of at least a truncated cone. Accordingly, the insulating body 18 has a right free end face 28 and an opposite free end face 30. Furthermore, the insulating body 18 has individual fold lines 32, 34, which are located in the Fig. 1 are partially represented by dashed lines. Between one free end face 28 and the adjacent first bend line 32, the insulating body 18 is formed in the shape of a truncated cone 36. Furthermore, between the first bend line 32 and the adjacent second bend line 34, the insulating body 18 can be provided with a second truncated cone 38. Additionally, between the second bend line 34 and the other free end face 30, another truncated cone 40 can be attached. Furthermore, the conical directions of the truncated cone 36 and the at least one further truncated cone 38, 40 are opposite to each other. Continuing the terminology, a circumferential interface 42 is to be formed on the outer circumference of the insulating body 18 between one free end face 28 and the first bend line 32.

[0032] In each outer end region of the interface 42, a field control element 20, 22 is provided. These field control elements 20, 22 define the interface 42 in the axial direction. The field control elements 20, 22 comprise an outer circumferential surface 43, which preferably merges flush with the interface 42. Furthermore, the field control elements 20, 22 comprise a contact surface 44, which is oriented outside the outer circumferential surface 43 with respect to the interface 42. This contact surface 44 is preferably angled relative to the outer circumferential surface 43. For example, the contact surface 44 of the field control element 20, which is associated with the end face 28 of the insulating body 18, can run parallel to this end face 28.In the opposite field control element 22, the contact surface 44 can extend along an outer circumference or a bending surface 33 of the insulating body 18, which is formed, for example, between the bending line 32 and an adjacent bending line 34.

[0033] The insulating body 18 preferably consists of ethylene propylene diene monomer (EPDM) rubber, which is available in a wide variety of compositions. Silicone rubber in various forms can also be used instead of EPDM. Furthermore, the high-voltage direct current cable 16, with a cable conductor 102, is surrounded on its outer circumference by cable insulation 46 and an outer conductive layer 103 on the cable insulation, in the usual manner. A funnel-shaped field control element 48, also known as an earth deflector, is mounted on the previously modified end 104 of the conductive layer, in a similarly conventional design, and is embedded in the insulating body 18 with an outwardly widening funnel.

[0034] Furthermore, the plug-in device 10 has a contact system 50 on its right side, comprising a contact ring 52, a clamping cone 54, and a pressure piece 56. This design is also common for such plug-in devices 10, so it will not be discussed in further detail here. In any case, it is ensured that a secure end termination for the high-voltage cable 16 is provided and that, in operation or when plugged in, the contact system 50 as a whole ensures the electrical connection to a contact socket 60 of the receiving device 12. The previously described assembly with the insulating body 18 is then connected to the contact system 50 of the plug-in device 10 on the other side.

[0035] In the Fig. 1 and Fig. The contact system 50 shown in Figure 2 differs from the usual design of such plug connectors in that a metallic energy storage element 59, in particular a spring device, is provided in the pressure piece 56. This ensures that an electrical contact between the field control element 20 and the pressure piece 56 is maintained permanently, regardless of temperature fluctuations.

[0036] Furthermore, the plug-in device 10 has a pressure sleeve 62 opposite the contact system 50. This sleeve, by means of a spring assembly 64 (part of a spring assembly 66), presses the insulating body 18 firmly against the inner wall or contact surface 26 of the receiving device 12 when the plug-in device 10 is connected to the receiving device 12. This ensures that any air gap 105 is avoided or reduced in volume as far as possible. The spring assembly 66 always provides the required pressure or clamping force, even in the event of thermal expansion of the insulating body that needs to be compensated for. In any case, this increases the electrical strength of the interface 42 between the insulating body 18 and the inner wall or contact surface 26 of the socket-shaped receiving device 12.

[0037] Furthermore, a funnel-shaped insulating sleeve 70 is attached between the spring assembly 66 and the insulating body 18. The insulating sleeve 70 acts as a barrier to prevent potential discharges along the metal / air interface in the event of a sheath fault, i.e., damage to the cable sheath (not shown). The insulating sleeve 70 rests with its outer circumference on the inner wall of the spring assembly 66 and extends to a so-called flange bell 72. The flange bell 72 widens in diameter and at least partially surrounds the pressure sleeve 62, transitioning into a plate-shaped flange part 74 for establishing the flange connection with another corresponding flange part 76 of the receiving device 12. The receiving device 12 is designed in the form of a bushing 78. Furthermore, the spring assembly 66 rests on the outer contour via the pressure sleeve 62.the contact surface 44 of the field control element 22, so that an electrical connection is always ensured.

[0038] The insulating sleeve 70 has an end section 71 that rests against a hinged surface 33. The contact surface 44 of the further field control element 22 is provided flush with this hinged surface 33. Preferably, a gap is formed between a front end of the end section 71 of the insulating sleeve 70 and the corresponding end of the contact surface 44. The pressure sleeve 62 can bear against the contact surface 44 with a pressing surface 63 that is oriented towards it and exert a pressing force on the contact surface 44.

[0039] To complete the description of the connector device 14 as a whole, it should be mentioned that the receiving device 12 comprises a socket 78, which is installed on high-voltage systems via a suitable pressure flange, which can be formed by the additional flange part 76. In this respect, the receiving device 12, together with the aforementioned components, forms a closed, and in particular gas-tight, unit. For optimal electric field control, metallic electrodes 82, 84 are integrated into the socket material of the socket-shaped receiving device 12 during its manufacture. The previously mentioned contact socket 60 at the tapered end of the socket 78 serves to ensure the electrical connection with the high-voltage line in the form of the cable 16 and the additional electrode 84.Alternatively, it can also be provided that the socket 78 has only one electrode 84 which is electrically connected to the contact socket 60.

[0040] In Fig. Figure 3 is a schematic longitudinal sectional view of an alternative embodiment of the plug connection device compared to the embodiment shown in the Fig. 1 and Fig. 2 shown. This embodiment differs in the design of the insulating sleeve 70. In this embodiment according to Fig. Figure 3 provides that the end section 71 of the insulating sleeve 70 extends at least to the contact surface 44 of the further field control element 22 and partially covers it. This means that the end section 71 of the insulating sleeve 70 overlaps the contact surface 44. Preferably, only a narrow circumferential end section of the contact surface 44 is covered by the insulating sleeve 70.

[0041] In Fig. 4 is the insulating body 18 according to the previously described plug-in device 10 in the Fig. 1, Fig. 2 to Fig. Figure 3 shows only the upper half in a schematic sectional view. The two field control elements 20, 22 are preferably identical in construction. Each of the field control elements 20, 22 has an angular shape in cross-section. For this purpose, the insulating body 18 has a recess or indentation 86 on its outer circumference, following the desired angular shape, into which a coating 88, for example in the form of conductive dispersions or conductive paint, is introduced, whereby the described closed outer contour of the spindle-shaped insulating body 18 is not compromised. The coating 88 can be sprayed on or applied by hand with a brush. The layer thickness of the coating 88 can be thin and, for example, be between 0.1 mm and 2 mm. In any case, the application of the coating 88 should avoid the formation of peaks or sharp-edged transitions at the interface 42 and the bending surface 33.

[0042] The course of the coating 88 to form the field control element 22 is as shown in the illustration. Fig. 1, Fig. 2 to Fig. 3 is selected such that, starting from the first bend line 32, the coating 88 extends the outer circumferential surface 43 towards the interface 42 and the contact surface 44 of the field control element 22 extends in the opposite direction towards a bend surface 33 of the insulating body 18. The ideal length of the coating 88 for forming the outer circumferential surface 43 is approximately 10 mm to 40 mm, while the length of the coating 88 along the bend surface 33 should be selected to be at most one-third of the total length of the bend surface 33.

[0043] The coating 88 profile for the field control element 20 is as follows: Fig. 1, Fig. 2 to Fig. 3 is selected such that the coating 88 forms an outer circumferential surface 43 which transitions flush into the interface 42. Furthermore, it is provided that the coating 88 extends along the end face 28 of the insulating body 18 to form the contact surface 44. By way of example, it is provided that the outer circumferential surface has a length of 30 mm to 50 mm and that the end face 28 of the insulating body 18 is completely covered.

[0044] In Fig. Figure 5 shows an alternative embodiment of the field control elements 20, 22. A field control element 20 is attached to or integrated as an insert 91 on the free end face 28 of the insulating body 18. This field control element is preferably designed as a circular sector and continues the conicity of the insulating body 18 along its outer circumference. In particular, this first field control element 20 is flush with the free end face 28 of the insulating body 18 and is connected to it without an air gap, for example, by vulcanizing its elastomeric material to the comparable elastomer of the insulating body 18. The preferred radius of the circular sector of the first field control element 20 is between 30 mm and 50 mm. In addition to the circular sector shape, the field control element 20 is designed such that the entire end face of the insulating body 18 remains conductive.In this respect, a field control element 20 made of conductive material can be integrated into the conical end 28 of the insulating body 18 as an extension, and in particular, the aforementioned first field control element 20 can also be connected to the insulating body 18 as a prefabricated component in larger quantities. In this embodiment according to the... Fig. In section 5, an arc-shaped insert 90 is placed in a corresponding recess 86 in the insulating body 18 for the second field control element 22. In cross-section, this insert forms a kind of circular sector. The preferred radius of the circular sector of the field control element 22 is between 10 mm and 40 mm and should not exceed one-third of the total length of the bending surface 33.

[0045] Another embodiment of the insulating body 18 is shown in Fig. 6 shown. The first field control element 20 corresponds, for example, to the embodiment in Fig. 5. The further field control element 22 can again be a prefabricated insert 92, which, viewed from the outer circumferential surface 43 towards the end face 30 of the insulating body 18, has a polygonal cross-section and is formed integrally with the earth deflector 48. The modified insert 92 extends radially to the interface 42 and can thus encompass the outer circumferential surface 43, the contact surface 44, the bending surface 33, and further surface sections up to the free end face 30. The length of the modified second field control element 22 along the interface 42 can ideally be between 10 mm and 40 mm.

[0046] It should also be mentioned at this point that all components used in the plug connection device 14 are rotationally symmetrical to the longitudinal axis of the device and in particular form hollow cylinder structures to allow the passage of the high-voltage direct current cable 16.

[0047] In Fig. Figure 7 shows a longitudinal section of another alternative embodiment of the plug connection device 14. In this embodiment, the plug connection device 10 includes an insulating body 18 with field control elements 20, 22 arranged thereon, according to... Fig. 6 includes. Due to the embodiment of the field control element 22 in the form of the insert 92 according to Fig.6 requires that the end section 71 of the insulating sleeve 70 extends completely along the pressure sleeve 62 or along the pressing surface 63 of the pressure sleeve 62, or at least slightly beyond it. The end section 71 of the insulating sleeve 70 extends such that a free contact surface 44 remains on the field control element 22. The area of ​​the contact surface 44 not covered by the insulating sleeve 70 borders the air gap 101 or the other adjacent interfaces of the receiving device 12 and the pressure sleeve 62. The pressure sleeve 62 may be made of an insulating material.

[0048] The embodiment according to the invention with attached or embedded control elements represents a significant improvement over the prior art. In particular, the field enhancement in the illustrated air gaps was effectively suppressed, while the existing charge activities were effectively attenuated. Accordingly, the use of field control elements has succeeded in reducing the local field strengths in air gaps and at air / insulating material interfaces.

Claims

[1] Plug-in device (10) for detachable insertion into a receiving device (12) for establishing an electrical connection between a high-voltage direct current cable (16) and a high-voltage operating device, - with an insulating body (18) that at least partially surrounds the high-voltage direct current cable (16), characterized by , - that the insulating body (18) has an interface (42) along its outer surface and a field control element (20, 22) made of conductive material is provided at each end region of the interface (42), which delimits the interface (42), and - that the one field control element (20) assigned to a free end face (28) of the insulating body (18) is applied to or rests on the free end face (28) of the insulating body (18) as an insert or attachment part (91) or is applied as a coating (88), and that the second field control element (22), which is arranged opposite the one field control element (20) on the insulating body (18), is designed as a coating (88) or is applied and / or inserted as an insert or attachment part (90, 92). [2] Plug-in device (10) according to claim 1, characterized by , that the field control elements (20, 22) each have an outer circumferential surface (43) which merges flush into the interface (42) of the insulating body (18) and each have a contact surface (44) outside the interface (42) which merges into or borders the outer circumferential surface (43). [3] Plug-in device (10) according to claim 1 or 2, characterized by, that the respective field control element (20, 22) is mounted on and / or incorporated into the insulating body (18), preferably in the form of a coating (88) or in the form of an insert or attachment part (90, 91, 92), which is preferably prefabricated. [4] Plug-in device (10) according to claim 3, characterized by , that the respective insert or attachment part (90, 91, 92) is made of elastically compliant, conductive elastomer, such as silicone rubber or ethylene propylene diene rubber, which preferably consists of the same base material as the insulating body (18). [5] Plug-in device (10) according to claim 3, characterized by , that the coating (88) consists of a conductive dispersion or a conductive lacquer, which is applied as a spray application or by hand with a brush to the insulating body (18), preferably in a circumferential recess (86) thereof. [6] Plug-in device (10) according to one of claims 3 or 4, characterized by, that the respective insert or attachment part (90, 91) is designed as a closed ring body which includes the high-voltage direct current cable (16), or that the respective insert or attachment part (92) is designed as a closed ring body and an earth deflector (48) is integrated. [7] Plugging device (10) according to one of the preceding claims, characterized by , that the insulating body (18) has at least one truncated cone (36, 38, 40) which includes at least one kink line (32, 34) on its circumference, wherein the kink line (32) arranged at a distance from the end face (28) of the insulating body (18) separates the interface (42) from further sections of the truncated cone. [8] Plug-in device (10) according to claim 2, characterized by, that the respective field control element (20, 22) has, in cross-section to the longitudinal axis of the insulating body (18), an outer circumferential surface (43) and a contact surface (44) which are angled to each other, or which transition into each other in an arc shape, or which are polygonal in shape. [9] Plug-in device (10) according to one of the preceding claims, characterized by , that a contact system (50) is arranged adjacent to the insulating body (18) and pointing in the insertion direction towards the receiving device (12), which consists of at least a contact ring (52) and a clamping cone (54), wherein a pressure piece (56) is arranged between the clamping cone (54) and an end face (28) of the insulating body (18), and preferably the pressure piece (56) has a metallic energy storage element (59) by which the pressure piece (56) is held in contact with the field control element (20) to maintain an electrical connection. [10] Plug-in device (10) according to one of the preceding claims, characterized by , that a pressure sleeve (62) is provided opposite to the insertion direction into the receiving device (12) against the insulating body (18), which has a pressing surface (63) that directly or indirectly abuts the contact surface (44) of the further field control element (22), and preferably the pressure sleeve (62) with a force storage element (64) presses the insulating body (18) into the receiving device (12) via the contact surface (44) of the further field control element (22). [11] Plug-in device (10) according to claim 10, characterized by , - that an insulating sleeve (70) is provided which extends from a flange bell (72) surrounding the high-voltage direct current cable (16) towards the insulating body (18) and an end section (71) of the insulating sleeve (70) overlaps the contact surface (44) of the further field control element (22) in the form of the coating (88) or the insert or attachment part (90) and only partially covers it, or - that the end section (71) of the insulating sleeve (70) rests against a bending surface (33) of the insulating body (18) at a distance from the contact surface (44) of the further field control element (22) in the form of the coating (88) or the insert or attachment part (90), or - that the end section (71) of the insulating sleeve (70) extending from the flange bell (72) extends at least between the pressing surface (63) of the pressure sleeve (62) and the contact surface (44) of the further field control element (22) in the form of the insert or attachment part (92), but does not completely overlap the contact surface (44). [12] Plug connection device (14) with a plugging device (10) according to one of the preceding claims, which is designed in the form of a plug and interacts with the receiving device (12) in the form of a socket (78), which can be coupled to each other by means of a flange connection (74, 76), characterized by , - that in the coupled arrangement of the plug-in device (10) in the receiving device (12), the field control elements (20, 22) and the interface (42) of the insulating body (18) arranged between them, as well as the outer circumferential surface (43) of the field control elements (20, 22), bear against a contact surface (26) of the receiving device (12), and further interface surfaces of the plug-in device (10) and the receiving device (12) are assigned to each other outside the field control elements (20, 22), wherein these further interface surfaces bear against each other or at least an air gap (100, 101) is formed between them, and - that the field control elements (20, 22) reduce the local electric field strengths at the interfaces or in the at least one air gap (100, 101) to a level that prevents an exceedance of the electrical strengths of the at least one air gap (100, 101) and their further interfaces of the plug-in device (10) and the receiving device (12). [13] Plug connection device (14) according to claim 12, characterized by , that a pressure sleeve (62) is provided on the plugging device (10) which, by means of a spring assembly (64), presses the interface (42) of the insulating body (18) flatly against the conical contact surface (26) of a socket (78) of the receiving device (12). [14] Plug connection device (14) according to claim 12 or 13, characterized by, that at least one electrode (82, 84) is provided in the socket (78), wherein one electrode (84) is assigned to and electrically connected with a contact socket (60), and that the outer circumferential surface (43) of the field control element (20) does not exceed the height of the metallic electrode (84), and if a further electrode (82) is provided in the socket (78), which is positioned at a distance from the first electrode (84) and is at an earth potential, the outer circumferential surface (43) of the further field control element (22) does not exceed the height of the electrode (82). [15] Plug connection device (14) according to one of claims 12 to 14, characterized by , that on the side facing away from the insulating body (18) a flange bell (72) is arranged which has a flange part (74) for making the flange connection with another flange part (76) of the bushing (78).

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