CN220232914U

CN220232914U - Current transformer for 10kV high-voltage reactive compensation

Info

Publication number: CN220232914U
Application number: CN202321014527.0U
Authority: CN
Inventors: 刘显峰; 刘百良; 马涛; 张仲魁
Original assignee: Hengyuan Litong Electric Factory Co ltd
Current assignee: Hengyuan Litong Electric Factory Co ltd
Priority date: 2023-04-28
Filing date: 2023-04-28
Publication date: 2023-12-22
Anticipated expiration: 2033-04-28

Abstract

The utility model relates to a current transformer for 10kV high-voltage reactive compensation, which comprises a transformer body and a base, wherein the transformer body is arranged on the base, the upper part of the transformer body is a transformer body, the lower part of the transformer body is a connecting part for connecting the base, the transformer body is in a non-closed ring shape, an iron core and a secondary winding arranged on the iron core are arranged in the transformer body, and a lightning arrester is arranged in the base. The utility model has simple structure and convenient installation, has lightning protection function, and is beneficial to improving or enhancing electromagnetic performance.

Description

Current transformer for 10kV high-voltage reactive compensation

Technical Field

The utility model relates to a current transformer suitable for a power network/power cable, in particular to a current transformer for 10kV high-voltage reactive compensation.

Background

The existing current transformer comprises a current transformer for a 10kV power distribution network, wherein the current transformer is a through type current transformer, the main body part of the current transformer is in a closed ring shape, a closed ring-shaped iron core and a secondary winding wound on the iron core are arranged in the current transformer, and a cable passes through a hole (or a bus hole) in the center of the ring to play a role of a primary winding, so that the structure of the current transformer is simplified, and the original layout mode of the cable is not changed. For example, chinese patent document CN205028770U discloses a penetrating-discharging type current transformer, comprising an iron core housing, an insulating support and a base, which are integrally structured and connected in sequence; the iron core shell is of a cuboid hollow sealing structure, a bus hole is formed in the middle of the iron core shell, and the bus hole is a rectangular through hole; an iron core is placed in the iron core shell, the iron core is a closed annular iron core, a cuboid hollow structure is adopted, the iron core is matched with the shape of the iron core shell, and a secondary winding is wound on the iron core; the insulating support is cylindrical, and a plurality of layers of umbrella skirts are arranged on the periphery of the insulating support along the axial lead direction of the insulating support; the base is cylindrical base, is provided with a cuboid arch on the base outer wall, is provided with a plurality of binding posts on the cuboid arch, passes the busbar (cable) that will detect during the use from current transformer's busbar hole, need not to cut off the busbar, simple to operate is swift, has reduced the tie point to small, light in weight occupies cabinet body space little. Chinese patent document CN115420912a discloses a combined sensor with electromagnetic electronic composite insulation through-core, wherein the single-phase combined sensor is in a through-core structure, the main body part is in a ring shape, the iron core in the main body is a closed ring-shaped iron core, and three single-phase sensors are adopted to respectively realize three-phase electric A, B, C three-phase measurement. Because of the need of passing cables through bus holes in the ring shape of the transformer, the current transformer is particularly installed or replaced after the power line is erected, the field construction is complex, and the power cables are usually cut off to be perforated, so that the operation of a power grid is hindered.

In order to facilitate the on-site assembly and disassembly of the transformer on the power line, open (open-close) type current transformer technology has been proposed and developed. For example, chinese patent document CN215643949U is an open-type current transformer, including first transformer shell and second transformer shell, first transformer shell with the outside of the leftmost end of second transformer shell is provided with the mount pad be fixed with the slide rail on the both sides wall of mount pad inboard, just first transformer shell with the second transformer shell can slide on the slide rail be fixed with the bearing on the bottom surface of mount pad, the inboard of bearing is fixed with a lead screw, have two relative screw threads on the lead screw, just first transformer shell with the second transformer shell sets up respectively on two screw threads of lead screw, the lead screw run through in the upper surface of mount pad and be connected with the regulation handle, the iron core divide into two parts, install respectively in first transformer shell and second transformer shell, after the transformer assembly is accomplished, the both ends of the interior adaptation iron core of first transformer shell and the interior adaptation of second transformer shell are in turn into complete annular iron core each other with the shape of the iron core of second transformer shell. The Chinese patent document CN113593814A discloses an open-type current transformer and a manufacturing method thereof, the open-type current transformer comprises a shell and an annular iron core, the shell comprises an upper shell and a lower shell, the upper shell is movably connected with the lower shell, the iron core comprises an upper iron core contained in the upper shell and a lower iron core contained in the lower shell, a secondary winding is wound on the lower iron core, and after the transformer is assembled, two ends of the upper iron core and two ends of the lower iron core are mutually combined to form a closed annular iron core. The Chinese patent document CN110136942A discloses an outdoor open-type combined current transformer of silicon rubber, which is characterized in that a first iron core and a second iron core are obtained by cutting a circular iron core, a first silicon rubber jacket is wrapped outside the first iron core to obtain a primary system, a wire package is formed by winding the outside of the second iron core, a second silicon rubber jacket is wrapped outside the wire package to obtain a secondary system, and then the primary system and the secondary system are fastened and combined together through a throat hoop to obtain the circular current transformer. The transformer can be opened in a ring shape when being installed on site, a cable is placed at the position of a bus hole, then two halves forming the ring shape are combined together and fixed, the cable is not required to be cut off or changed, the difficulty of on-site assembly and disassembly is obviously reduced, the complexity of the transformer is brought, and due to relatively large error/difference of the two halves of the ring shape, an ideal ring-shaped iron core cannot be formed, and the output characteristics of different transformers in the site are also greatly different.

In addition, these current transformers do not have a lightning protection function, and in some cases, an additional lightning arrester is required, which results in complexity of the system and the construction process.

In addition, the basic construction of the existing current transformer is set based on a low-voltage distribution system, and when used in a power transmission system or a high-and medium-voltage distribution system, for example, a 10kV or more distribution line, there is a problem of adaptability due to saturation current, remanence, and the like or a place to be further improved.

Disclosure of Invention

In order to overcome the defects in the prior art, the utility model provides the current transformer for 10kV high-voltage reactive compensation, which is simple in structure, convenient to install and has a lightning protection function.

The technical scheme of the utility model is as follows: the current transformer for 10kV high-voltage reactive compensation comprises a transformer body and a base, wherein the transformer body is arranged on the base, the upper part of the transformer body is a transformer body, the lower part of the transformer body is a connecting part for connecting the base, an iron core and a secondary winding (or called secondary coil) arranged on the iron core are arranged in the transformer body, and a lightning arrester is arranged in the base.

Preferably, the lightning arrester is arranged at the front part of the base, and a grounding bolt extending downwards is arranged, and the grounding bolt is exposed from the bottom surface of the front part of the base.

Further, a vertical round hole is formed in the top surface of the rear portion of the base and is used as a mounting hole of the transformer body, the mounting hole can be a blind hole or a through hole if necessary, and the base is vertically penetrated.

The connecting portion of the transformer body may be a downwardly extending cylinder (or referred to as a cylinder), and is inserted into a mounting hole (a circular hole serving as a mounting hole of the transformer body) on the base, and is interference fit with the mounting hole.

Preferably, the top surface of the front part of the base is provided with a wire clamp.

The wire clamp can be any suitable prior art, for example, the wire clamp is provided with an upper clamp plate and a lower clamp plate, the lower clamp plate is fixedly connected with the top surface of the front part of the base, and the upper clamp plate is connected with the lower clamp plate through clamp plate bolts at two sides.

Further, the transverse middle parts of the upper clamping plate and the lower clamping plate are all in arc shapes (or cylindrical shapes) for clamping the cables, and the height of the lower clamping plate (particularly the height of the arc shapes) is suitable for the height of the cables, so that the cables penetrating through the transformer main body can not be obviously bent due to unsuitable positions of the heights of the wire clamps when the transformer is used.

Typically, the transformer body is annular, i.e., a cylinder with a cross-section that is not closed.

Preferably, the transformer body is in the form of a non-closed ring, i.e. a cylinder with a cross-section of a non-closed ring, said non-closed ring being in the form of a ring with an opening/gap.

Optionally, the notch on the non-closed loop is located on the top or side of the non-closed loop.

Preferably, the non-closed loop is a non-closed circular loop.

Preferably, the end surfaces of the two ends (corresponding to the two ends of the non-closed annular notch) of the transformer body are all plane surfaces.

Further, the end surfaces of the two ends of the transformer body are parallel to each other, are equal in size and are opposite to each other (vertical projections on any plane parallel to the two are overlapped with each other).

Preferably, the end faces of the two ends of the iron core (corresponding to the two ends of the non-closed ring-shaped notch) are plane.

Further, the end surfaces of the two ends of the iron core are parallel to each other, equal in size and opposite to each other.

The width of the non-closed annular gap (i.e., the distance between the end faces of the transformer body) should generally be greater than the outer diameter of the cable to be tested in order to facilitate the insertion of the cable through the gap and into the transformer body.

Preferably, the transformer main body and the base are both formed by solidification of insulating materials, the iron core and the secondary coil are solidified in the insulating materials of the transformer main body, and the lightning arrester is solidified in the insulating materials of the base.

Optionally, the method comprises the step of. The transformer body is provided with or without a housing. When the transformer body is provided with a shell, the shell of the transformer body is fixedly connected to the outer side of the insulating material of the transformer body.

Optionally, the base is provided with or without a housing. When the base is provided with a shell, the shell of the base is fixedly connected with the outer side of the insulating material of the base,

further, the casing of the transformer body may only wrap the transformer body, or may be a unified casing of the transformer body, wrapping the whole transformer body (the transformer body and the connection portion).

Preferably, the insulating material may be vulcanized silicone rubber.

Preferably, the end surfaces at two ends of the iron core are fixedly connected in the insulating material, the main body shell is provided with end surfaces at two ends of the notch, that is, the main body shell seals the end surfaces of the transformer main body at the notch, and the iron core is not exposed.

The beneficial effects of the utility model are as follows: the base is arranged, and the umbrella skirt is arranged on the peripheral surface (side surface) of the base, so that the installation on a pole tower or other installation bases is facilitated; because the lightning arrester is arranged in the base, the lightning arrester function is realized, and the safety is improved; because the mutual inductor body and the base are in interference fit under the plugging of the hole column, the connecting structure between the two is simplified, and the connecting strength and the reliability are ensured; the cable clamp for clamping the cable is arranged on the top surface of the front part of the base, so that the cable is fixed and stable equivalent to the main body of the transformer; because the ring-shaped of the transformer main body is provided with the opening (notch), the cable can be directly sleeved in the ring-shaped through the opening, and the cable can pass through the bus hole without being cut off as in the conventional through type current transformer during installation; the iron cores (and the secondary coils) are in a non-closed ring shape similar to the non-closed main body, so that the end faces of the two iron core split bodies are not required to be separated and then are re-combined like the existing open type current transformer during installation, the air gap errors generated by the end face combination and the air gap differences among products are avoided, the detection precision and the consistency of the relevant characteristics of the products are improved, and meanwhile, an opening and closing fixing device between the two iron core split bodies is not required to be arranged, so that the structure of the transformer is simplified; the end face of the iron core is not exposed, so that damage is reduced, reliability of detection data is guaranteed, and service life is prolonged; due to the fact that the gap is formed in the iron core, equivalent magnetic permeability is obviously increased, magnetic resistance is increased, saturation current is further reduced obviously, residual magnetism is reduced obviously, linearity in an actual measurement range is improved, and measurement reliability and accuracy are improved.

According to the characteristics of the power network/cable under higher voltage, the utility model overcomes the long-term technical bias that the iron core of the current transformer needs to adopt a closed magnetic ring or a quasi-closed (only with a tiny air gap) magnetic ring, and can be better suitable for medium-high voltage distribution systems (for example, 10kV distribution systems) and other similar occasions.

Drawings

Fig. 1 is a schematic perspective view of a current transformer according to the present utility model;

FIG. 2 is a schematic diagram of a side view configuration of the current transformer of FIG. 1;

FIG. 3 is a schematic perspective view of the transformer body of the current transformer of FIG. 1;

fig. 4 is a schematic diagram showing a front view of a configuration of a transformer body in the current transformer shown in fig. 1;

FIG. 5 is a schematic diagram of a side view configuration of a transformer body in the current transformer of FIG. 1;

fig. 6 is a schematic diagram of a front view configuration of another transformer body that may be used in the base of the current transformer of fig. 1;

fig. 7 is a schematic perspective view of a base of the current transformer of fig. 1;

FIG. 8 is a schematic diagram of a side view configuration of a base in the current transformer of FIG. 1;

FIG. 9 is a schematic top view of a base in the current transformer of FIG. 1;

fig. 10 is a schematic diagram showing a front view of a structure of a transformer body according to the present utility model;

fig. 11 is a schematic diagram showing a front view of another transformer body according to the present utility model.

Detailed Description

Referring to fig. 1 to 11, such a current transformer is composed of two parts, in which a transformer body can be regarded as an independent current transformer, a base 40 is used for installation on a tower or the like, and a lightning arrester 45 is built in to achieve a lightning protection function, and the transformer body is fixedly installed on the base.

The portion of the transformer body for performing the detection function is a transformer body (abbreviated as a main body) 10, and a connection portion (or a connection portion) 30 for fixedly connecting with the base is provided on the transformer body to form the transformer body.

The transformer body 10 is annular (the front view is annular), and may be rectangular annular or other annular according to practical needs, for example, the inner edge and the outer edge are both racetrack-shaped annular, and the annular is provided with an opening/notch 14 which is non-closed annular. Such a non-closed loop can be considered as a segment of a complete closed loop (closed loop) that is left after the segment is cut off, the cut off area forming a gap.

The core 20 and the secondary winding are disposed in the transformer body, and the transformer body may be prepared by casting an insulating material, and the core (including the secondary winding on the core) is supported/fixed in a suitable position in a mold by a suitable supporting/fixing method, and a connection (which may be called a secondary wire or a secondary wire) 18 of the secondary winding is led out, and if necessary, a connection terminal (secondary terminal) of the secondary wire is disposed. And pouring the liquid (for example, molten) insulating material into a mould, and solidifying to form the transformer body with the iron core and the secondary coil into an integrated solid structure. For the base, it can also be prepared in a similar manner.

When the transformer main body is provided with a shell (including a unified shell provided with the whole transformer), the shell can be used as a mould (external mould), if necessary, other mould components are used for casting and forming, and after the insulating material is solidified, the shell is solidified on the outer surface of the transformer main body (or the outer surface of the whole transformer). When the vulcanized silicone rubber is adopted as the insulating consolidation material, a silicone rubber vulcanization molding process can be adopted to prepare the main body of the transformer or the integral transformer. When the base is provided with a housing, it can also be prepared in a similar manner.

When the transformer body is integrated with other constructions (e.g., the connection portion of the transformer body) and the same insulating material is used, a case adapted to the integrated construction may be provided, that is, the transformer body may share one (a set of) cases with other related constructions, and the insulating material is poured at one time to be consolidated and molded.

The end surfaces 16 at both ends of the main body are respectively located at both sides of the notch, and both end surfaces (the main parts of the end surfaces) are plane surfaces, and can be arranged in parallel and opposite directions, so that the inner width and the outer width of the notch are equal. According to actual needs, the two end surfaces can be not parallel to each other, and an included angle is formed between the planes of the two end surfaces (the planes of the end surfaces), so that a notch with narrow inside and wide outside is formed. During installation, the cable 1 can be sleeved in the non-closed annular ring space (the corresponding closed annular ring space/the central through hole can be regarded as the non-closed annular ring space) 11 through the notch, and then the mutual inductor is fixed on an adaptive installation basis (for example, a cross arm and a bus frame) according to actual needs.

The iron core can adopt an axial lamination structure, and a plurality of silicon steel sheets (or microcrystal, amorphous lamination, etc.) with the same shape are sequentially laminated and fixed into a whole along the axial direction to form the iron core. According to actual needs, a plurality of lamination sheets (silicon steel sheets and/or microcrystalline/amorphous lamination sheets and the like) with gradually changed lengths can be adopted to be sequentially stacked inside and outside. The core end faces (major portions of the end faces) 26 are planar, and may be disposed in parallel and opposite relation, and for non-closed toroidal cores or in other suitable cases, the core end faces may be longitudinal or in other orientations. When the two end surfaces of the iron core are plane and are parallel and opposite, the magnetic force lines in the radial middle area between the two end surfaces are basically straight lines perpendicular to the two end surfaces and are uniformly distributed (the magnetic field intensity is the same), and the magnetic force lines in the peripheral area of the end surfaces are diffused curves. The magnetic leakage caused by the arrangement of the notch can be obviously reduced by adopting the structure with opposite end surfaces.

Under the condition of meeting the installation requirement (allowing the cable to enter the non-closed ring through the notch, namely, the width of the notch is larger than the outer diameter of the cable), the influence on the electromagnetic performance can be considered by the arrangement of the width of the notch, and the optimization design can be carried out through corresponding software or experiments. Experiments have shown that compared with the iron core/transformer main body which is in a closed ring shape in the prior art, the arrangement of a certain notch can obviously reduce saturation current, obviously reduce remanence, obviously improve the linearity degree in the actual measurement range, and is beneficial to improving or improving the performance of the current transformer in a medium-high voltage distribution system or other similar occasions.

A preferred option is: the circumferential length of the non-closed ring-shaped notch (the length of the center line, or the length of the line connecting the midpoints of the longitudinal sections, may be regarded as the center of the longitudinal section of the notch area at the midpoint of the longitudinal section of the notch area) may be 1/8 to 1/4 of the circumferential length of the ring-shaped notch (the center circumference of the ring-shaped, for example, the sum of the four sides of the center rectangle of the rectangular ring-shaped).

The notch on the non-closed ring shape may be provided on the top (see fig. 4 and 10) or on one side (see fig. 6 and 11) as required.

For example, in the embodiment shown in fig. 1, the upper half of the transformer body is a transformer body 10, which is in a non-closed ring shape, a notch 14 is provided at the top, and an iron core (silicon steel sheet iron core or other laminated iron core) 20 and a secondary coil are provided in the top for current collection of the circuit. The lower half of the transformer body is a cylinder 30 which is used as a connecting part and is used for being inserted and fixed on a base, and a secondary wire is led out from the bottom of the cylinder (connecting part).

The base has a cylindrical basic profile, the cross section of the main body portion can be regarded as a rounded rectangle, the top surface of the base has a stepped shape, and a portion of the base located on the front side of the top surface stepped elevation 44 (the portion of the base) can be referred to as a base front portion 41, and a portion located on the rear side of the top surface stepped elevation (the portion of the base) can be referred to as a base rear portion 42.

The top surface of the front part of the base and the top surface of the rear part of the base are both horizontal planes, and the front top surface (the top surface of the front part of the base) is higher than the rear top surface (the top surface of the rear part of the base).

The top surface of the back part 42 of the base is provided with a vertical fixing hole 43 for plugging the connecting part of the transformer body, the size (aperture) of the vertical fixing hole is slightly smaller than the outer diameter of the connecting part (cylinder or slightly tapered round table with big top and small bottom) 30 of the transformer body, the connecting part of the transformer body is plugged on the vertical through hole of the base and is in interference fit with the base (the vertical through hole of the base), the front part of the base is internally provided with a lightning arrester, the lightning arrester is provided with a grounding stud 46 exposed from the bottom part of the base (particularly the bottom part of the front part of the base), the top surface of the front part of the base is provided with a wire clamp 50, the wire clamp consists of an upper clamping plate 53 and a lower clamping plate 52, the transverse (left and right) middle parts of the upper clamping plate and the lower clamping plate are in reverse (the arc on the cross section) and the arc of the other clamping plate, the arc of the upper clamping plate is upwards convex, the arc of the lower clamping plate downwards convex, the lower clamping plate and the top surface of the base are fixedly connected (for example, through bolts/screws and embedded structures fixedly built in the base), the left and right sides of the upper clamping plate can be fastened with bolts 55 (and nuts matched with the bolts, if needed, the left and right sides of the base are connected with the lower clamping plates, the wire clamp 1 and the wire clamp is placed on the upper clamping plate and the corresponding wire clamp and the upper clamping plate and the lower clamping plate and the wire clamp is placed on the upper clamping plate and the lower clamping plate by the upper clamping plate and the lower clamping plate and the wire clamp by the wire clamp. The arc-shaped inner side of at least one of the upper clamping plate and the lower clamping plate is provided with a puncture nail, and after the cable is clamped and fixed by the wire clamp, the puncture nail penetrates through the outer insulating layer of the cable and is reliably connected with a wire (primary wire) inside the cable.

The circumferential surface (side surface) of the base may be provided with a shed 43.

The base may be cylindrical in basic shape, rectangular in horizontal cross section with rounded corners, and longer in front-to-back direction than in left-to-right direction, to facilitate placement of the base front and rear halves in relation to each other.

In the above embodiment, the 10kv line 600 can be satisfied ² The following products with wires penetrating (passing) have been validated in the field.

The preferred and optional technical means disclosed in the present utility model may be arbitrarily combined to form a plurality of different specific embodiments unless otherwise specified and when one preferred or optional technical means is further defined as another technical means.

Claims

1.10kV high voltage reactive power compensation current transformer, including the transformer body, its characterized in that still includes the base, and the transformer body is installed on the base, and its upper portion is the transformer main part, and the lower part is the connecting portion that is used for connecting the base, and the inside of transformer main part is equipped with the iron core and sets up the secondary winding on the iron core, is provided with the arrester in the base.

2. The current transformer for 10kV high voltage reactive power compensation according to claim 1, wherein the lightning arrester is disposed at the front portion of the base, and a grounding bolt extending downward is provided, the grounding bolt being exposed from the bottom surface of the front portion of the base.

3. The current transformer for 10kV high-voltage reactive power compensation according to claim 1, wherein a vertical round hole is formed in the top surface of the rear portion of the base and is used as a mounting hole of the transformer body, and the connecting portion of the transformer body is a cylinder extending downwards and is inserted into the mounting hole in the base to be in interference fit with the mounting hole.

4. The current transformer for 10kV high-voltage reactive power compensation according to claim 1, wherein a wire clip is provided on a top surface of the front portion of the base.

5. A current transformer for 10kV high voltage reactive compensation according to any of claims 1-4, characterized in that the transformer body has a non-closed loop shape.

6. The current transformer for 10kV high-voltage reactive power compensation according to claim 5, wherein the end surfaces of the two ends of the iron core are plane surfaces, and the end surfaces of the two ends of the iron core are parallel to each other, equal in size and opposite to each other.

7. The current transformer for 10kV high voltage reactive power compensation according to claim 5, wherein the width of the non-closed annular gap is larger than the outer diameter of the cable to be detected.

8. A current transformer for 10kV high voltage reactive power compensation according to any of claims 1-4, wherein the transformer body and the base are each consolidated from an insulating material, the core and the secondary winding are consolidated within the insulating material of the transformer body, and the lightning arrester is consolidated within the insulating material of the base.

9. The current transformer for 10kV high-voltage reactive compensation according to claim 8, wherein the insulating material is vulcanized silicone rubber.

10. The current transformer for 10kV high voltage reactive power compensation according to claim 8, wherein the transformer body is provided with or without a case, the base is provided with or without a case, the case of the transformer body is fixedly attached to the outer side of the insulating material of the transformer body when the transformer body is provided with the case, and the case of the base is fixedly attached to the outer side of the insulating material of the base when the base is provided with the case.