Device for protecting against partial discharges

Abstract

The invention relates to a device for protecting against partial discharges, said device comprising a connector comprising: - a housing (20); - an insulator (22) positioned inside the housing (20) and comprising a through-hole; - an electrical conductor (21) positioned inside the through-hole of the insulator (22); noteworthy in that the insulator (22) comprises a conductive layer (23) on part of the outer surface of the insulator (22), said conductive layer (23) being positioned between the housing (20) and the insulator (22).

Description

Description Title of the invention: Partial discharge protection device Technical field of the invention

[0001] The present invention relates to a partial discharge protection device. It applies, in particular, in the field of electrical insulation and connectivity. Prior art

[0002] Assembling a connector component with insulation requires functional clearances between the parts. This results in the presence of air gaps between the parts. From an electric field value in the air zone, partial discharges appear in these air gaps and these discharges lead to degradation of the insulation and then premature breakdown of the insulation.

[0003] At altitude, the pressure is reduced, which facilitates the occurrence of partial discharges. The voltage resistance of the insulation is therefore reduced at altitude.

[0004] Some prior art documents also propose partial discharge protection devices. For example, publication document EP4092689 is known, which describes an electrical cable limiting partial discharges.

[0005] However, this invention may have drawbacks and cannot be transposed to connectivity.

[0006] There is also document US2017294770 and document 2010115769 without however satisfying the needs mentioned below. Presentation of the invention

[0007] The present invention aims to overcome these drawbacks with a completely innovative approach.

[0008] More specifically, the invention aims to provide a device eliminating partial discharges in air zones.

[0009] In particular, one objective of the invention is to provide such a technique making it possible to do away with any other complex adjustment system.

[0010] An objective of the invention is to provide such a device, which can be easily adapted to existing systems.

[0011] These objectives, as well as others which will appear subsequently, are achieved, according to a first aspect, using a partial discharge protection device, said device comprising a connector comprising: - a case; - an insulator positioned inside the housing and comprising a through hole; - an electrical conductor positioned inside the through hole of the insulator; remarkable in that the insulator comprises a first conductive layer on a portion of the outer surface of the insulator, said conductive layer being positioned between the housing and the insulator; the insulator comprises a second conductive layer on a portion of its inner surface, the end of the first conductive layer or the second conductive layer extends beyond the housing and on either side of the housing.

[0012] Thanks to these provisions, the second conductive layer makes it possible to minimize partial discharges between the insulator and the electrical conductor. In one embodiment, the conductive layer is obtained by surface preparation by abrasion, application of sparing, chemical metallization layer then electrodeposition.

[0013] Thanks to these provisions, this protection device by metallizing the insulators makes it possible to limit the occurrence of partial discharges by very significantly reducing the electric field in the layer of air located between the external face of the insulator and the casing.

[0014] According to one variant, the housing is of circular cylindrical shape. According to another variant, the housing is of circular cylindrical shape with a flattened surface.

[0015] According to one variant the case is rectangular in shape.

[0016] The invention is advantageously implemented according to the embodiments and variants set out below, which are to be considered individually or in any technically effective combination.

[0017] In one embodiment, the electrical conductor comprises a contact surface with the insulator.

[0018] In one embodiment, the insulator extends between two ends, each end comprising an end insulator and / or an elastomeric part.

[0019] Thanks to these provisions, the end insulator and / or the elastomer part makes it possible to eliminate triple points. A triple point (air-insulator-conductor interface) is a point of concentration of the electric field which facilitates the occurrence of partial discharges.

[0020] Thanks to these provisions, this extension of the insulation makes it possible to move the triple point away from the device.

[0021] In one embodiment, the ends of the first conductive layer or the second conductive layer are covered by a flexible seal.

[0022] Thanks to these provisions, the seals provide a seal and cut off leakage lines between the electrical conductor and the housing.

[0023] In one embodiment, the connector includes seals positioned between the insulator and the housing or between the insulator and the electrical conductor and covering the end of the conductive layers.

[0024] Seals, for example, O-rings, maintain high pressure between the housing and the insulation, which reduces the occurrence of partial discharges. Brief description of the figures

[0025] Other advantages, aims and characteristics of the present invention emerge from the following description given, for explanatory and non-limiting purposes, with reference to the appended drawings, in which:

[0026] Figure 1 shows an application of a partial discharge protection device;

[0027] Figure 2 shows another partial discharge protection device;

[0028] Figure 3 represents the association of the two previous partial discharge protection devices;

[0029] Figure 4 shows a partial discharge protection device using a coating;

[0030] Figure 5 shows a partial discharge protection device with an extension of the insulator;

[0031] Figure 6 shows a partial discharge protection device with a clip;

[0032] Figure 7 shows an isometric view of the partial discharge protection device;

[0033] Figure 8 shows an exploded view of the assembly of the protection device with the connector;

[0034] Figure 9 shows a sectional view of the assembly of the protection device with the connector;

[0035] Figure 10 represents a detail view of the previous figure. Description of the embodiments

[0036] Figure 1 shows an application of a partial discharge protection device.

[0037] The sample application shows components.

[0038] The components are: a housing 20, an electrical conductor 21, and an insulator 22.

[0039] According to one variant, the housing 20 is of circular cylindrical shape, and it is assembled with an electrical conductor 21.

[0040] According to another variant, the housing 20 is of circular cylindrical shape with a flat surface.

[0041] A land is a flat or crushed surface of a generally cylindrical or bar-shaped object, which is used to provide a specific contact area or bearing surface in a given application.

[0042] The housing 20 provides protection for the electrical conductor 21 and the insulator 22, and allows the retention of the insulator 22.

[0043] According to one variant, the housing 20 is metallic or made of metallized plastic, and connected to electrical ground.

[0044] The insulator 22 has a conductive layer 23, and a through hole, and is positioned inside the housing 20.

[0045] The conductive layer 23 is positioned on the outer surface of the insulator 22.

[0046] The conductive layer 23 is shown as a black line in the figure.

[0047] According to one variant, the conductive layer 23 is conductive or semi-conductive. This makes it possible to obtain a zero electric field between the insulator 22 and the housing 20, and therefore to avoid partial discharges in the air layer between the two parts.

[0048] The term partial discharge translates to an electrical breakdown in an air layer. The air layer in question concerns functional clearances between the housing 20 and the insulator 22.

[0049] The onset voltage of partial discharges can be calculated using Paschen's law.

[0050] Paschen's law is an empirical law that allows us to determine the voltage at which an electric arc appears in a gas.

[0051] An empirical law is a functional relationship based on observation and experience, rather than on logical deduction or mathematical demonstration.

[0052] According to one variant, the conductive layer 23 comprises a contact surface with the housing 20.

[0053] Depending on the connector environment, the gaps are filled with air or another gas.

[0054] The device shows clearances between the insulator 22 and the electrical conductor 21.

[0055] The electrical conductor 21 is positioned inside the hole passing through the insulator 22.

[0056] The use of an electrical conductor 21 allows the transport of electrical power.

[0057] The electrical conductor 21 has a contact surface with the insulator 22.

[0058] According to one variant, the electrical conductor 21 is composed of male and female electrical contacts connected to a cable or a bus bar.

[0059] Naturally, the invention is described in the foregoing by way of example. It is understood that those skilled in the art are able to carry out different variant embodiments of the invention without departing from the scope of the invention.

[0060] Figure 2 shows another partial discharge protection device.

[0061] This example has the same characteristics as the previous figure but with one major difference.

[0062] According to one variant, the insulator 22 comprises a conductive layer 23 on its inner surface.

[0063] This conductive layer 23 makes it possible to reduce the risk of partial discharges occurring between the electrical conductor 21 and the insulator 22.

[0064] Figure 3 shows the combination of the two previous partial discharge protection devices.

[0065] The insulator 22 has a conductive layer 23 on its inner and outer surface.

[0066] This association makes it possible to minimize the occurrence of partial discharge throughout the invention.

[0067] Figure 4 shows a partial discharge protection device using a coating.

[0068] This figure represents the same characteristics as the previous figures but with the addition of a coating.

[0069] A flexible seal is positioned at the ends of the insulation 22.

[0070] According to one example, the flexible seal consists of elastomeric parts, or of a complementary end insulator 26.

[0071] The use of a flexible seal provides a seal and ensures the protection function at different pressures subjected to the connector 21.

[0072] An elastomeric part is a part made from an elastomeric material, which is a type of polymer material with elastic properties. Elastomers are characterized by their ability to deform under stress or force, and to return to their original shape and size when the stress is released.

[0073] The use of multiple elastomeric parts or an additional end insulator 26 makes it possible to eliminate triple points.

[0074] The triple points represent the junction between the air, the insulator 22, and the electrical conductor 21 or the conductive layer 23. The position of the triple points causes partial discharges to appear, hence the use of a coating.

[0075] According to a variant, the complementary end insulator 26 is an insulating coating such as paint or varnish.

[0076] Alternatively, the triple points are eliminated by compressing elastomer parts, which eliminates the presence of air in this area.

[0077] Alternatively, the elastomer parts are O-rings.

[0078] O-rings are circular ring-shaped sealing parts made from elastomeric materials.

[0079] According to one variant, the elastomeric parts are compressed by insulating end parts 26.

[0080] The use of end insulating pieces 26 also allows the path distances and air gaps to be extended to increase the breakdown voltage.

[0081] The end insulating pieces 26 are positioned outside the housing 20.

[0082] Figure 5 shows a partial discharge protection device with an extension of the insulator 22.

[0083] This figure has the same characteristics as the previous figures.

[0084] The extension of the insulator 22 extends vertically, and goes around the housing 20.

[0085] The conductive layer 23 located on the outer surface of the insulator 22 is extended between the housing 20 and the extension of the insulator 22.

[0086] The extension of the 22 insulator allows the triple points to be moved away from the connector 21.

[0087] Figure 6 shows a partial discharge protection device with a clip and an electrical contact.

[0088] This figure has the same characteristics as the previous figures.

[0089] In an example of an electrical connector, single-way or multi-way, retention clips are used to ensure the retention of electrical contacts. These clips are made of insulating (plastic) or conductive material. In both cases, these clips have complex geometries with tip shapes and feature triple points with a local increase in the electric field. These areas are at higher risk of partial discharges occurring.

[0090] The solution described above is used to increase the voltage value of the occurrence of partial discharges, by metallizing the cavity where the clip is located.

[0091] Figure 7 shows an isometric view of the partial discharge protection device.

[0092] An isometric view generally refers to a three-dimensional graphical representation of an object or scene in space using an isometric projection.

[0093] The isometric view represents the assembly of the device with the electrical conductor.

[0094] Figure 8 shows an exploded view of the assembly of the protective device with the electrical conductor 21.

[0095] The electrical conductor 21 is a connecting bar made of conductive material (e.g. copper or nickel, possibly with surface treatment) to which cables (lugs) or busbars can be connected by screwed assembly (bolt) using the two holes.

[0096] In another embodiment, cables may be connected to the electrical conductor by crimping.

[0097] A metal (or metallized plastic) feed-through box 20 allows attachment to a partition and connection to ground.

[0098] An insulator 22 and an end insulator 26, metallized on the surface, provide electrical insulation.

[0099] An end insulator 26 screwed over the housing 20 allows the path distances between the electrical conductor 21 and the housing 20 to be increased and the flexible insulating seal 25 to be compressed.

[0100] A flexible insulating gasket 25 and a flexible interfacial insulating gasket prevent electrical tracking and breakdown between the connector and the housing.

[0101] An elastic ring allows the retention of the insulator 23 and the end insulator 26.

[0102] 25 O-rings ensure the seal of the passage.

[0103] Figure 9 shows a sectional view of the assembly of the protection device with the electrical conductor 21.

[0104] Figure 10 shows a view of details A, B and C defined in the previous figure and of the ends of the conductive layers 23.

[0105] These three details represent the stops of the metallization in the device.

[0106] Details A and B show the ends of the conductive layers 23 covered by the joints 25.

[0107] Detail C shows one end of conductive layer 23 terminating in an area where there is no risk of partial discharges.

[0108] It is emphasized that all features, as they emerge for a person skilled in the art from this description, the drawings and the attached claims, even if they have been specifically described only in relation to other specific features, both individually and in any combinations, may be combined with other features or groups of features disclosed herein, provided that this has not been expressly excluded or that technical circumstances make such combinations impossible or meaningless. LIST OF REFERENCE SIGNS

[0109] [Table 1]

Claims

Claims Claim 1. Partial discharge protection device, said device comprises a connector comprising: - a housing (20); - an insulator (22) positioned inside the housing (20) and comprising a through hole; - an electrical conductor (21) positioned inside the through hole of the insulator (22); characterized in that the insulator (22) comprises a first conductive layer (23) on a portion of the outer surface of the insulator (22), said conductive layer (23) being positioned between the housing (20) and the insulator (22); the insulator (22) has a second conductive layer (23) on a portion of its inner surface, the end of the first conductive layer (23) or the second conductive layer (23) extends beyond the housing (20) and on either side of the housing (20). Claim 2. Device according to claim 1, in which the electrical conductor (21) has a contact surface with the insulator (22). Claim 3. Device according to claim 1, in which the insulator (22) extends between two ends, each end comprising an end insulator and / or an elastomeric part. Claim 4. Device according to claim 1, in which the ends of the first conductive layer (23) or of the second conductive layer (23) are covered by a flexible seal (25). Claim 5. Device according to claim 1, in which the connector comprises seals positioned between the insulator (22) and the housing (20) or between the insulator (22) and the electrical conductor (21) and covering the end of the conductive layers.

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