CN114905438A

CN114905438A - Conductor positioning device for leakage mutual inductor and leakage detection equipment

Info

Publication number: CN114905438A
Application number: CN202210626366.4A
Authority: CN
Inventors: 赖建树; 魏秀玲; 邹盛俊; 肖峰
Original assignee: ABB Schweiz AG
Current assignee: ABB Schweiz AG
Priority date: 2022-06-02
Filing date: 2022-06-02
Publication date: 2022-08-16
Anticipated expiration: 2042-06-02
Also published as: CN114905438B

Abstract

The present disclosure relates to a conductor positioning device (1) for a leakage transformer (2) and an associated leakage protection apparatus. The conductor positioning device (1) comprises: a stopper for mounting on a first hole (21) of the earth leakage protection device and defining a second hole (41, 51, 61) allowing a conductor to be detected to pass therethrough; wherein the second aperture is defined within the area covered by the first aperture. In particular, when the limiting member is mounted on the first hole (21), the second hole is positioned within a circular area with a diameter D/2, centered on the center of the first hole (21), where D is the diameter of the first hole (21). By utilizing the conductor positioning device (1) and the related leakage protection equipment, the measurement precision and the anti-interference capability can be effectively improved.

Description

Conductor positioning device for leakage mutual inductor and leakage detection equipment

Technical Field

The present disclosure relates to the field of electrical leakage detection, and more particularly, to a conductor positioning device and an electrical leakage detection apparatus for an electrical leakage transformer.

Background

Leakage transformers (also known as zero sequence transformers) are widely used in industrial and domestic applications for fault detection of leakage.

Typically, the leakage transformer is a single-turn feedthrough current transformer, and the working principle is as follows: the method comprises the following steps that a to-be-detected three-phase cable is used as a primary side circuit to penetrate through an iron core window hole on a mutual inductor, under a normal condition, three-phase current in the primary side circuit is basically balanced, and generated synthetic magnetic flux is close to zero; when an electric shock or an electric leakage fault occurs in the primary side circuit, the generated resultant magnetic flux is not equal to zero, so that zero sequence current can be output at the secondary side of the transformer, and equipment connected on the primary side circuit can be further enabled to start protection actions (power supply cutting, alarming and the like) so as to realize an electric leakage or fault protection function.

Disclosure of Invention

One of the objectives of the present disclosure is to provide a conductor positioning device for a leakage transformer, which can effectively improve the detection accuracy and/or the anti-interference capability of the leakage transformer.

According to a first aspect of the present disclosure, there is provided a conductor positioning device for a leakage transformer having a first hole allowing a conductor to be detected to pass therethrough, the conductor positioning device comprising: a stopper for being mounted on the first hole and defining a second hole for allowing the conductor to pass therethrough; wherein the second aperture is defined within the area covered by the first aperture.

It is easily understood that, with the conductor positioning device of the present disclosure, the position of the conductor to be detected in the magnetic field environment in the first hole may be limited, which may help the conductor to be detected to be in a relatively more uniformly distributed or uniform magnetic field environment, which may help improve the detection accuracy and/or the interference rejection capability of the leakage transformer.

In some embodiments, when the retaining member is mounted on the first hole, the second hole is positioned within a circular region of diameter D/2 centered on the center of the first hole, where D is the diameter of the first hole. In this way, the conductor to be detected can be further in a basically consistent magnetic field environment, so that the detection precision and/or the anti-interference capability of the leakage transformer are further improved.

In some embodiments, when the retaining member is mounted on the first hole, the center of the second hole coincides with the center of the first hole. In this way, the conductor to be detected can be brought to an intermediate position of the first hole. It will be readily appreciated that the magnetic field environment is relatively uniformly distributed and uniform at the mid-position of the first bore.

In some embodiments, the retaining member is formed by a combination of a first retaining member and a second retaining member, and the first retaining member and the second retaining member are adapted to be respectively mounted to the first hole from two opposite sides of the first hole. In this way, the mounting convenience of the stopper is improved.

In some embodiments, the first retaining member and the second retaining member each have an annular portion and an outer flange extending from the annular portion, both of the annular portions collectively defining the second bore, wherein an outer diameter of the annular portion is equal to a diameter of the first bore, an inner diameter of the annular portion is equal to a diameter of the second bore, and an outer diameter of the outer flange is greater than the diameter of the first bore. In these embodiments, the first retaining member and the second retaining member may be better positioned on the first hole by the design of the annular portion and the outer flange.

In some embodiments, the first retaining member and the second retaining member are both identical in shape and are adapted to be fastened to each other by a screw connection. In this way, both the first limiting member and the second limiting member can be fixed conveniently.

In some embodiments, the first retaining member and the second retaining member are each formed by two halves. In this way, the mounting convenience of the first stopper and the second stopper can be further improved.

In some embodiments, the retaining member has a hollow shaft portion having an outer diameter equal to the diameter of the first hole and two resilient flange portions extending from opposite ends of the hollow shaft portion, the inner diameter of the hollow shaft portion defining the second hole, the outer diameter of the resilient flange portions being greater than the diameter of the first hole; wherein the elastic flange portion is designed to allow passing through from one side of the first hole to the other side of the first hole with deformation thereof. It will be readily appreciated that this embodiment provides another type of limiter. With this type of stop, it is likewise convenient to mount the stop on the first hole.

In some embodiments, the retainer has a slot in a lateral direction, the slot being configured to penetrate from a radial tip of the flange portion to an inner surface of the hollow shaft portion and to allow the conductor to enter the second hole from a lateral direction through the slot. In this way, the conductor can be easily mounted to the second hole of the stopper.

In some embodiments, the stopper is an integrally molded elastomer.

In some embodiments, the retaining member is a hard ring having an inner diameter equal to the diameter of the second hole and an outer diameter equal to or smaller than the diameter of the first hole, so as to allow the hard ring to be directly inserted into the first hole in the axial direction of the first hole. It will be readily appreciated that this embodiment provides yet another type of limiter. With this type of stop, it is likewise possible to facilitate the mounting of the stop on the first hole.

In some embodiments, the conductor positioning device further comprises a shielding case for being sleeved outside the leakage transformer to shield external magnetic field interference, wherein the shielding case comprises the first shielding piece and the second shielding piece which are combined and shaped with each other, the first shielding piece and the second shielding piece are combined and define a third hole, and the edge of the third hole is suitable for abutting against and supporting the hard annular piece from the side direction so that the hard annular piece is stably arranged on the first hole. In this way, the magnetic field shielding can be provided for the leakage transformer, and meanwhile, the stable support can be provided for the limiting part.

According to a second aspect of the present disclosure, there is provided an electrical leakage detection device. The electric leakage detection apparatus includes: a leakage transformer having a first hole allowing a conductor to be detected to pass therethrough; and a conductor positioning device according to the first aspect.

It should also be understood that the statements described in this summary are not intended to limit the key or critical features of the embodiments of the disclosure, nor are they intended to limit the scope of the disclosure. Other features of the embodiments of the present disclosure will become readily apparent from the following description.

Drawings

The above and other features, advantages and aspects of various embodiments of the present disclosure will become more apparent by referring to the following detailed description when taken in conjunction with the accompanying drawings. In the drawings, like or similar reference characters designate like or similar elements, and wherein:

fig. 1 shows a schematic view of a conductor positioning device mounted on a leakage transformer according to a first example embodiment of the present disclosure;

fig. 2 shows an exploded schematic view of a conductor positioning device together with a leakage transformer of a first example embodiment of the present disclosure;

fig. 3 shows a schematic view of a conductor positioning device mounted on a leakage transformer according to a second example embodiment of the present disclosure;

fig. 4 shows an exploded schematic view of a conductor positioning device together with a leakage transformer of a second example embodiment of the present disclosure;

fig. 5 shows a schematic view of a conductor positioning device mounted on a leakage transformer according to a third example embodiment of the present disclosure; and

fig. 6 shows an exploded schematic view of a conductor positioning device together with a leakage transformer of a third example embodiment of the present disclosure.

Detailed Description

Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While certain embodiments of the present disclosure are shown in the drawings, it is to be understood that the present disclosure may be embodied in various forms and should not be construed as limited to the embodiments set forth herein, but rather are provided for a more thorough and complete understanding of the present disclosure. It should be understood that the drawings and embodiments of the disclosure are for illustration purposes only and are not intended to limit the scope of the disclosure.

As described above, the leakage transformer (or the zero sequence transformer) is widely used in industrial and household applications for fault detection of leakage and the like. In particular, the measurement accuracy of the leakage transformer is of great importance. However, the inventors noted that: in some conventional designs, the manufacturing materials and manufacturing processes of the leakage transformer have a large influence on the magnetic field distribution within its core aperture, which results in the measurement accuracy of the leakage transformer being influenced even by the placement of the conductor (such as a cable) when passing through the aperture of the leakage transformer.

In order to reduce this effect and to improve the measurement accuracy of various types of leakage transformers as much as possible, the inventors realized that: it may be beneficial to confine the conductor to be detected (such as a cable) within a localized area within the core aperture of the leakage transformer, particularly a circular area having a diameter no greater than 1/2 of the diameter of the first aperture of the leakage transformer centered around the center of the core aperture, as it may provide a more uniform magnetic field environment for the conductor to be detected (such as a cable).

To this end, the idea of the present disclosure is to provide a conductor positioning device for a leakage transformer, which may particularly comprise the following limit stops: the stop may be configured such that a second hole defined by the stop for allowing a conductor to be tested, such as a cable, to pass therethrough may be positioned within the area covered by the first hole of the leakage transformer when the stop is mounted on the first hole of the leakage transformer. Further, the coverage area of the second holes is smaller than that of the first holes. In particular, the second hole may be positioned within a circular area of diameter D/2 centered on the center of the first hole of the leakage transformer, where D is the diameter of said first hole. It is easy to understand that in this arrangement, the arrangement position of the conductor (such as a cable) on the leakage transformer is limited, which contributes to improving the measurement accuracy of different types of leakage transformers.

For a better understanding of the above concept, fig. 1 shows a schematic view of a conductor positioning device mounted on a leakage transformer according to a first example embodiment of the present disclosure; and fig. 2 shows an exploded schematic view of a conductor positioning device together with a leakage transformer of a first example embodiment of the present disclosure.

As shown in fig. 1 and 2, the conductor positioning device 1 comprises a retaining member 4 adapted to be mounted in the first hole 21 of the leakage transformer 2, while the retaining member 4 itself defines a second hole 41. It will be readily appreciated that both the first aperture 21 and the second aperture 41 described above may allow a conductor to be detected (such as a cable) 3 to pass therethrough, and that in the mounted state of the stop 4, the second aperture 41 will be positioned within the area covered by the first aperture 21. It will be readily appreciated that this may constrain the position of the conductor within the first bore 21, which may help promote consistency of the magnetic field environment in which the plurality of conductors (such as cables) are passed through.

The conductor 3 to be tested is shown in fig. 1 as a three-phase four-wire cable by way of example only. It will be understood, however, that the present disclosure is not limited to the type, number, or number of conductors of different phases. For example, the conductor may be a cable, and the cable may be, for example, a three-phase five-wire cable, a single-phase two-wire cable (neutral + live), or even a single neutral N, etc. Further, the conductor may also be, for example, a copper bar or the like other than a cable. As understood by the person skilled in the art, the principle of the leakage transformer 2 is intended to measure zero sequence current (i.e. unbalanced current) on the conductor 3, so long as the number of conductors and the number of different phases are arranged to be suitable for determining whether the conductor is leaky based on the detection principle of the leakage detector.

It is also easy to understand that once the zero sequence current is measured, meaning that an electric shock or leakage fault may occur in the conductor 3 as the primary line, then a protective action (power cut, alarm, etc.) may be activated for the equipment connected to the conductor 3.

In particular, as previously discussed, the diameter of the second aperture 41 may also be defined as 1/2 being smaller than the diameter D of the first aperture 21. It will be readily appreciated that in the manner described above, it is advantageously possible to constrain the position of the conductors within the first bore and in particular to allow the plurality of conductors 3 to be ensured to be in a substantially uniform magnetic field environment as they pass through both of their bores.

As an example, in the mounted state of the limiting member 4, it may be more advantageous to define the second hole 41 in a circular region 1/2 centered at the center of the first hole 21 and having a diameter of the diameter D of the first hole, because when the second hole 41 is so positioned, it may be easier to ensure that the plurality of conductors 3 are in a substantially uniform magnetic field environment, thereby providing higher measurement accuracy. As a further example, when the limiting member is mounted on the first hole, the center of the second hole may be exactly coincident with the center of the first hole, thereby providing a more substantially uniform magnetic field environment for the plurality of conductors 3.

In this embodiment, in order to facilitate the installation of the limiting member 4 on the first hole 21, as shown in fig. 2, the limiting member 4 may further include a first limiting member 42 and a second limiting member 43, which may be combined to form the limiting member 4 and the second hole 41. In some embodiments, the first limiting member 42 and the second limiting member 43 are identical to each other in structure and shape. In still other embodiments, the first limiting member 42 and the second limiting member 43 may have different structures and shapes from each other.

Further, the first and

second stoppers

42 and 43 may be configured to be adapted to be mounted to the first hole 21 from two opposite sides of the first hole 21, respectively.

In some embodiments, the first retaining member 42 and the second retaining member 43 may each have an annular portion 44 and an outer flange 45 extending from the annular portion 44, wherein the outer diameter of the annular portion 44 may be equal to the diameter of the first hole 21, the inner diameter of the annular portion 44 is equal to the diameter of the second hole, and the outer diameter of the outer flange 45 is greater than the diameter of the first hole. In this manner, when the first retaining member 42 and the second retaining member 43 are assembled, the annular portion 44 will be adapted to extend into the first hole 21, and the outer flange 45 will act as a stop, i.e., prevent the retaining members from extending further into the first hole 21.

Further, as an example, the first limiting member 42 and the second limiting member 43 may be fixed to each other in a snap-fit manner. As another example, both the first stopper 42 and the second stopper 43 may be fastened to each other by screw connection. In these ways, when assembling these components, an operator may first pass the conductor 3 through one of the first limiting member 42 and the second limiting member 43, the first hole 21 of the leakage transformer 2, the other one of the first limiting member 42 and the second limiting member 43, and then mount the first limiting member 42 and the second limiting member 43 to the first hole 21 from the left and right sides of the leakage transformer 2.

In some embodiments, the first limiting member 42 and the second limiting member 43 can be further combined by two half pieces. This further improves the degree of freedom in design of the limiting member 4, and the convenience of installation. In this way, when assembling these components, the operator can assemble the first and

second stoppers

42 and 43, respectively, by first passing the conductor 3 through the first hole 21 of the leakage transformer 2 and then assembling the first and

second stoppers

42 and 43 to the first hole 21.

It will be readily appreciated that the conductor positioning device 1 of fig. 1 and 2 provides a simple way of locating the conductor 3 to be detected in the first hole 21 of the leakage transformer 2, which improves the detection accuracy of the leakage transformer 2.

Fig. 3 shows a schematic view of a conductor positioning device mounted on a leakage transformer according to a second example embodiment of the present disclosure; and fig. 4 shows an exploded schematic view of a conductor positioning device together with a leakage transformer of a second example embodiment of the present disclosure.

As shown in fig. 3 and 4, the conductor positioning device 1 comprises a limiting member 5 adapted to be mounted on the first hole 21 of the leakage transformer 2. Since the type and number of the leakage transformers 2 and the conductors 1 suitable for detection are the same as those shown in fig. 1, no further description is given. The structure of the stopper 5 will be described with emphasis.

The limiting member 5 has a second hole 51, and in the mounted state of the limiting member 5, the second hole 51 will be positioned within the area covered by the first hole 21. In particular, the diameter of the second hole 51 may be defined as 1/2 being smaller than the diameter D of the first hole 21. It will be readily appreciated that in this manner it is possible to ensure that the plurality of conductors are in a substantially uniform magnetic field environment as the plurality of conductors 3 pass through their two apertures.

As an example, in the mounted state of the limiting member 5, it may be more advantageous to define the second hole 51 in a circular region 1/2 centered at the center of the first hole 21 and having a diameter of the diameter D of the first hole, because when the second hole 51 is so positioned, it may be easier to ensure that the plurality of conductors 3 are in a substantially uniform magnetic field environment, thereby providing higher measurement accuracy. As a further example, when the limiting member is mounted on the first hole, the center of the second hole may be exactly coincident with the center of the first hole, so as to provide a more substantially uniform magnetic field environment for the plurality of conductors 3.

According to this embodiment, the limiting member 5 has a hollow shaft portion 52 and two elastic flange portions 53 extending from opposite ends of the hollow shaft portion, wherein the hollow shaft portion 52 has an outer diameter equal to the diameter of the first hole 21, the hollow shaft portion 52 has an inner diameter defining the second hole 51, and the elastic flange portions 53 have an outer diameter larger than the diameter of the first hole 21. Further, the elastic flange portion 53 may be designed to be capable of elastic deformation to allow one end of the limiting member 5 to pass from one side of the first hole 21 to the other side of the first hole 21, thereby achieving the mounting of the limiting member 5 on the first hole 21 on the leakage transformer 2. In this way, the assembly of the stopper can be simplified as compared with the assembly of the first embodiment. In some embodiments, the stop 5 may be integrally formed. However, in further embodiments, it is also possible that the stop 5 is not integrally formed. Furthermore, although in the above description it has been described that only the flange portion 53 is resilient, in further embodiments it is also possible to construct the whole of the limiting member 5 as an integral moulding and as a whole resilient, and this may be more preferred, as the resilient hollow shaft portion may more conveniently facilitate the passage of one end of the limiting member 5 through the first aperture 21.

To further facilitate the mounting of the limiting member 5 on the first hole 21, in some embodiments, the limiting member 5 may further have a slot 54 in the lateral direction, the slot 54 being configured to penetrate from the radial end of the flange portion to the inner surface of the hollow shaft portion 52. In this way, when the stopper 5 is an elastic body as a whole, the hollow shaft portion itself of the stopper 5 can be deformed more easily, thereby facilitating the mounting of the stopper 5 on the first hole 21 more easily. Furthermore, whether or not the hollow shaft portion 52 of the retaining member 5 is resilient, a sufficiently large slot may also allow the conductor to enter the second hole from a lateral direction via the slot 54, which promotes ease of installation of the conductor into the second hole 51.

During assembly, an operator may first pass the conductor 3 through the first hole 21 of the leakage transformer 2 and the second hole 51 of the limiting member 5, and then mount the limiting member 5 to the first hole 21 of the leakage transformer 2, so as to achieve the limiting mounting of the conductor on the first hole 21 of the leakage transformer 2.

It is easy to understand that the conductor positioning device 1 in fig. 3 and 4 provides a further simple way of restraining the conductor 3 on the first hole 21 of the leakage transformer 2, which improves the detection accuracy of the leakage transformer 2.

Fig. 5 shows a schematic view of a conductor positioning device mounted on a leakage transformer according to a third example embodiment of the present disclosure; and fig. 6 shows an exploded schematic view of a conductor positioning device together with a leakage transformer of a third example embodiment of the present disclosure.

As shown in fig. 5 and 6, the conductor positioning device 1 comprises a positioning member 6 adapted to be mounted on the first hole 21 of the leakage transformer 2. Since the type and number of the leakage transformer 2 and the conductors 3 suitable for detection are the same as those shown in fig. 1, no further description is given. The structure of the stopper 6 will be described with emphasis.

As shown in fig. 6, the retaining member 6 may be a hard ring-shaped member and defines a second hole 61. Depending on design, the hard collar may have an inner diameter equal to the diameter of the second bore and an outer diameter equal to or less than the diameter D of the first bore 21. In the mounted state of the limiting member 5, the second hole 61 will be positioned within the area covered by the first hole 21. In particular, the diameter of the second hole 61 may be defined as 1/2 being smaller than the diameter D of the first hole 21. It will be readily appreciated that in this manner it is possible to ensure that the plurality of conductors are in a substantially uniform magnetic field environment as the plurality of conductors 3 pass through their two apertures.

As an example, in the mounted state of the limiting member 6, it may be more advantageous to define the second hole 61 in a circular region 1/2 centered at the center of the first hole 21 and having a diameter of the diameter D of the first hole, because when the second hole 61 is so positioned, it may be easier to ensure that the plurality of conductors 3 are in a substantially uniform magnetic field environment, thereby providing higher measurement accuracy. As a further example, when the limiting member is mounted on the first hole, the center of the second hole may be exactly coincident with the center of the first hole, so as to provide a more substantially uniform magnetic field environment for the plurality of conductors 3.

In some embodiments, the stop member 6 may be integrally formed. In still other embodiments, the stop 6 may be formed from two halves. It is easily understood that, regardless of the molding method, the stopper 6 as a hard ring member is allowed to be directly fitted into the first hole 21 in the axial direction of the first hole 21. However, in the above manner, the stability of the limiting member 6 in the first hole 21 may be somewhat lacking.

To further secure the stop 6 on the first hole 21, in some embodiments this may be achieved, for example, by a shielding can 7 that is sleeved outside the leakage transformer 2 to shield external magnetic field disturbances.

Specifically, in some embodiments, the shield can 7 may include a first shield 71 and a second shield 72 that are shaped in combination with each other. As an example, the first shield 71 may be fitted over the upper part of the leakage transformer 2 and the second shield 72 may be fitted over the lower part of the leakage transformer 2. Both the first shield 71 and the second shield 72 may in combination define a third bore, the inner diameter of which may be equal to the outer diameter of the stop 6. Thus, when the first shield 71 and the second shield 72 are mounted, the edge 73 of the third hole can abut laterally against the rigid ring-shaped member, so that the rigid ring-shaped member is stably supported on the first hole 21. The first shield 71 and the second shield 72 may be fastened to each other by any fastening means (e.g., snap, screw means).

In some embodiments, the shield 7 may be made of a magnetically conductive or non-conductive metal material, such as steel, aluminum, copper, or the like.

Note that although the above describes the use of the shielding cage 7 for fastening the limiting member 6, in other embodiments it is also possible that the shielding cage 7 is used only for shielding external disturbances of the leakage transformer.

The process of assembling the respective components on the leakage inductor 2 will be briefly described below only with the shield case 7 having the function of fastening the stopper 6. Specifically, for example, in an embodiment directed to the stopper 6 as a hard ring that is integrally formed, the conductor 3 may be first passed through the first hole 21 of the leakage transformer 2 and the second hole 62 of the hard ring, then the hard ring is directly inserted into the first hole 21, and finally the first shield 71 and the second shield 72 are mounted on the leakage transformer 2 while supporting and stopping the edge of the hard ring. For another example, in an embodiment for a rigid ring shaped in two halves, the conductor 3 may first be passed through the first hole 21 of the leakage transformer 2, then the two halves of the rigid ring are directly plugged into the first hole 21, and finally the first shield 71 and the second shield 72 are mounted on the leakage transformer 2, thereby simultaneously supporting and limiting the edges of the rigid ring.

It is easy to understand that the conductor positioning device 1 in fig. 5 and 6 provides a further simple way of restraining the conductor 3 on the first hole 21 of the leakage transformer 2, which improves the detection accuracy of the leakage transformer 2.

Various embodiments of the conductor positioning device of the present disclosure and their corresponding installation processes have been described above in detail. It should be understood that the structure and installation process of the conductor positioning device described above is merely an example. Furthermore, in addition to the above-mentioned conductor positioning means intended to protect, the subject matter of the present disclosure may also relate to an earth leakage protection device, which may comprise the above-mentioned conductor positioning means.

It should also be appreciated that while the installation processes are described in the specification in a particular order, this does not require or imply that the installation processes must be performed in that particular order, or that all of the illustrated installation operations must be performed to achieve desirable results, but that the installation processes depicted may have varying orders of execution. Additionally or alternatively, certain operational steps may be omitted, multiple operational steps may be combined into one operational step execution, and/or one operational step may be broken down into multiple operational step executions.

It is also to be understood that while the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. For example, a person skilled in the art may arbitrarily combine the embodiments or features of the embodiments described above, as long as these embodiments or features are suitable for combination. For another example, a shield case for shielding external magnetic field interference may be applied to the first and second embodiments of the present disclosure.

In the claims, the word "comprising" does not exclude other elements, and the indefinite article "a" or "an" does not exclude a plurality. A single element or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain features are recited in mutually different embodiments or dependent claims does not indicate that a combination of these features cannot be used to advantage. The scope of protection of the present application covers any possible combination of features recited in the various embodiments or in the dependent claims, without departing from the spirit and scope of the application.

Furthermore, any reference signs in the claims shall not be construed as limiting the scope of the invention.

Claims

1. A conductor positioning device (1) for a residual current transformer (2), the residual current transformer (2) having a first hole (21) allowing a conductor to be tested to pass therethrough, the conductor positioning device (1) comprising:

a stopper (4, 5, 6) for mounting on the first hole (21) and defining a second hole (41, 51, 61) allowing the conductor to pass therethrough;

wherein the second aperture is defined within the area covered by the first aperture.

2. The conductor positioning device (1) according to claim 1, wherein the second hole (41, 51, 61) is positioned within a circular area of diameter D/2 centered on the center of the first hole (21) when the retaining piece (4, 5, 6) is mounted on the first hole (21), wherein D is the diameter of the first hole (21).

3. The conductor positioning device (1) according to claim 1 or 2, wherein the centre of the second hole coincides with the centre of the first hole (21) when the stop (4, 5, 6) is mounted on the first hole (21).

4. The conductor positioning device (1) according to claim 1 or 2, wherein the retaining member (4) is formed by a combination of a first retaining member (42) and a second retaining member (43) adapted to be mounted onto the first hole (21) from two opposite sides of the first hole (21), respectively.

5. The conductor positioning device (1) according to claim 4, wherein the first retaining member (42) and the second retaining member (43) each have an annular portion (44) and an outer flange (45) extending from the annular portion, the two annular portions together defining the second bore,

wherein the outer diameter of the annular portion (44) is equal to the diameter of the first bore (21), the inner diameter of the annular portion is equal to the diameter of the second bore, and the outer diameter of the outer flange (45) is greater than the diameter of the first bore (21).

6. The conductor positioning device (1) according to claim 5, wherein the first stop (42) and the second stop (43) are both identically shaped and adapted to be fastened to each other by a screw connection.

7. The conductor positioning device (1) according to claim 5 or 6, wherein the first stop (42) and the second stop (43) are each composed of two halves.

8. The conductor positioning device (1) according to claim 1 or 2, wherein the retainer (5) has a hollow shaft portion (52) and two resilient flange portions (53) extending from opposite ends of the hollow shaft portion, the hollow shaft portion (52) having an outer diameter equal to the diameter of the first hole (21), the hollow shaft portion having an inner diameter defining the second hole, the resilient flange portions (53) having an outer diameter greater than the diameter of the first hole (21);

wherein the resilient flange portion (53) is designed to allow passage from one side of the first aperture (21) to the other side of the first aperture (21) with deformation thereof.

9. The conductor positioning device (1) according to claim 8, the retaining piece (5) having a slot (54) in a lateral direction, the slot (54) being configured to penetrate from a radial extremity of the flange portion (53) to an inner surface of the hollow shaft portion (52) and to allow the conductor to enter the second hole (51) from the lateral direction via the slot (54).

10. The conductor positioning device (1) according to claim 8, the stop (5) being an integrally formed elastomer.

11. The conductor positioning device (1) according to claim 1 or 2, the retaining member (6) being a hard ring having an inner diameter equal to the diameter of the second bore and an outer diameter equal to or smaller than the diameter of the first bore (21) to allow direct insertion of the hard ring into the first bore (21) in the axial direction of the first bore (21).

12. Conductor positioning device (1) according to claim 11, further comprising a shielding cage (7) for sheathing outside the leakage transformer (2) for shielding external magnetic field disturbances,

the shielding cage (7) comprises a first shielding piece (71) and a second shielding piece (72) which are shaped to be combined with each other, the first shielding piece (71) and the second shielding piece (72) are combined to define a third hole, and the edge (73) of the third hole is suitable for abutting against and supporting the hard annular piece from the side direction so that the hard annular piece is stably arranged on the first hole (21).

13. An electrical leakage detection apparatus comprising:

a leakage transformer (2) having a first hole (21) allowing a conductor to be detected to pass therethrough; and

conductor positioning device (1) according to any of claims 1-12.