Grounding type voltage transformer with fuse

Abstract

The utility model discloses a grounding type voltage transformer with a fuse, and relates to the technical field of high-voltage measurement or relay protection equipment of an electric power system. Comprising a voltage transformer body arranged in a main insulator, the voltage transformer body comprises a primary winding, a secondary winding and an iron core, the secondary winding and the primary winding are concentrically wound on the iron core from inside to outside, the primary winding is formed by arranging a plurality of enameled round copper wires in parallel into a strand and winding the strand in a pagoda mode from inside to outside in a grading mode, and the secondary winding is wound on the iron core. Insulation paper is arranged between every two adjacent layers of enamelled round copper wires, a layer of primary high-voltage electrostatic screen is wound on the outer side of each level and is separated from the enamelled round copper wires by the insulation paper, and the width of the primary high-voltage electrostatic screen is larger than that of the insulation paper between the corresponding levels; a primary insulating cylinder is arranged at the top of the transformer body, the fuse is sealed in the primary insulating cylinder by adopting a sealing head bolt and a silica gel pad, and a primary high-voltage terminal is arranged on the primary insulating cylinder. The device is smaller in occupied space, simple in maintenance, uniform in internal and external electric fields, small in partial discharge amount and safe and reliable in operation.

Description

Technical Field

[0001] The utility model relates to the technical field of high-voltage measurement or relay protection equipment in an electric power system, in particular to a grounding voltage transformer with a fuse. Background Art

[0002] Voltage transformers are similar to transformers in that they are instruments used to transform the voltage on a line. However, the purpose of a transformer transforming voltage is to transmit electrical energy, while the purpose of a voltage transformer transforming voltage is mainly to power measuring instruments and relay protection devices, and to measure the voltage, power, and electrical energy of the line. Therefore, the capacity of a voltage transformer is very small, generally only a few volt-amperes or tens of volt-amperes, and the maximum does not exceed one thousand volt-amperes.

[0003] The basic structure of a voltage transformer is very similar to that of a transformer. It also has two windings, one called the primary winding and the other called the secondary winding. When AC current flows through the primary winding, AC magnetic flux is generated in the iron core, inducing voltage in the secondary winding. Although the primary voltage is very high, the secondary voltage is low, which can ensure the safety of operators and instruments and facilitate the detection of voltage in high-voltage lines.

[0004] During the use of voltage transformers, when a short circuit occurs in the line and the current increases sharply, fuses are often used to disconnect the circuit to prevent damage to the line due to excessive current. However, traditional voltage transformers with fuses have many components, uneven internal and external electric fields, and very strict requirements on size and insulation quality. They are relatively complicated to install and maintain, and there are many quality control points. Otherwise, it will affect the overall performance of the voltage transformer and pose a hidden danger to the actual operation safety of the switch cabinet. Utility Model Content

[0005] The purpose of the utility model is to provide a grounded voltage transformer with fuse, which is made of epoxy resin vacuum casting and has multiple advantages such as small size, flexible installation, easy maintenance, uniform internal and external electric fields, and small local discharge.

[0006] To achieve the above-mentioned purpose, the present application proposes a grounded voltage transformer with a fuse, comprising a voltage body built into a main insulator, wherein the voltage body comprises a primary winding, a secondary winding and an iron core, wherein the secondary winding and the primary winding are concentrically wound on the iron core from the inside to the outside, and is characterized in that the primary winding is a plurality of enameled round copper wires arranged in parallel as a strand and wound in a graded pagoda shape from the inside to the outside, an insulating paper is provided between two adjacent layers of enameled round copper wires, a primary high-voltage electrostatic screen is wound on the outside of each level, and is separated from the enameled round copper wire by the insulating paper, and the width of the primary high-voltage electrostatic screen is greater than the width of the insulating paper between the corresponding layers; a primary insulating cylinder is provided on the top of the voltage body, and a head bolt and a silicone pad are used at the front end of the primary insulating cylinder to seal the fuse in the primary insulating cylinder, and a primary high-voltage terminal is provided on the primary insulating cylinder.

[0007] Furthermore, the primary high-voltage electrostatic screen is a flexible composite paper with rubber strips on both sides and a whole semi-conductive crepe paper structure wrapped outside. The cross section of the primary high-voltage electrostatic screen is flat in the middle and smooth and convex on both sides.

[0008] Furthermore, a threaded nut is provided in the front end of the primary insulating cylinder, the threaded nut is connected to the primary high-voltage terminal, and the head bolt passes through the silicone pad and cooperates with the threaded nut to seal the fuse.

[0009] Furthermore, the primary winding is connected to a primary wiring insert, which is fixed on a primary insulating cylinder. A spring in the primary insulating cylinder is fixed by a screw, and the spring abuts against the rear end of the fuse. The primary wiring insert is threadedly connected to the shielding net.

[0010] Furthermore, a primary grounding N terminal and a secondary wiring terminal are arranged on the secondary wiring platform at the lower front side of the main insulator, and the grounding terminal is arranged at the rear end of the main insulator.

[0011] Furthermore, the main insulator is an integrated structure formed by casting the voltage body, the primary insulating tube, the primary high-voltage terminal, the screw sleeve nut, and the secondary wiring platform with epoxy resin, and the integrated structure is installed as a whole on the installation base plate.

[0012] Furthermore, the main insulator is a rectangular parallelepiped structure, and the lower part of the four edges thereof is a missing-corner structure.

[0013] Furthermore, the end of the shielding net is an arc-shaped nut metal piece, and the outer periphery of the arc-shaped nut metal piece is a cylindrical wire mesh and extends to one side.

[0014] As a further step, the shielding net is arranged in the epoxy resin of the primary insulating cylinder and is located at the outer periphery of the fuse.

[0015] As a further step, the head bolt is a metal bolt, the nut of which is plum blossom-shaped and is formed by vacuum casting of epoxy resin.

[0016] Compared with the prior art, the above technical solution adopted by the utility model has the following advantages:

[0017] 1. Small size, light weight, and many advantages: Optimized structural design, the screw sleeve bolt and the primary insulation cylinder are integrated into a structure that is more compact as a whole; the voltage transformer integrates various functions such as fuse protection and conductivity, reduces the size, occupies less space, is conducive to product miniaturization, and is light in weight and full in function, making it more suitable for use as a new type of voltage transformer supporting the switch cabinet;

[0018] 2. Easy installation and maintenance: When installing and using, you only need to install the voltage transformer in the switch cabinet according to the phase sequence, without the need to install other electrical accessories, which effectively saves the assembly time of the switch cabinet; it is even simpler during maintenance, and there is no need to remove the wiring at one time. You only need to unscrew the head bolts to repair or replace the fuse;

[0019] 3. Uniform electric field, stable insulation and safe operation: The primary insulating cylinder adopts a shielding net and a primary winding equipped with an electrostatic screen, which work together to achieve a better shielding effect, uniform internal and external electric fields, small local discharge, and safe and reliable operation; it is made of integral casting of epoxy resin, with reliable insulation, saving a large number of electrical connection components, effectively avoiding many quality risks in design, and ensuring safer operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a cross-sectional view of a grounding voltage transformer with fuse;

[0021] Figure 2 This is the main view of the grounding voltage transformer with fuse;

[0022] Figure 3 It is the side view of the grounding type voltage transformer with fuse;

[0023] Figure 4 It is a top view of a grounding voltage transformer with fuse;

[0024] Among them: 1. Primary winding; 2. Voltage body; 3. Primary high-voltage electrostatic screen; 4. Main insulator; 5. Secondary wiring platform; 6. Mounting base plate; 7. Secondary wiring terminal; 8. Secondary protective cover; 9. Grounding terminal; 10. Shielding net; 11. Primary wiring insert; 12. Fuse; 13. Head bolt; 14. Threaded nut; 15. Primary high-voltage terminal; 16. Silicone pad; 17. Primary insulating cylinder. DETAILED DESCRIPTION

[0025] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0026] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0027] In the description of the present application, it should be understood that the terms "center", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0028] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0029] This embodiment provides a grounding type voltage transformer with fuse, including a main insulator, which is an integrated structure formed by casting a voltage body 2, a primary insulating cylinder 17, a primary high-voltage terminal 15, a screw sleeve nut 14, and a secondary terminal 5 with epoxy resin, and the integrated structure is located on the installation base plate;

[0030] like Figure 1 As shown, the voltage body 2 includes a primary winding 1, a secondary winding and an iron core, wherein the secondary winding and the primary winding 1 are concentrically wound on the iron core from the inside to the outside, the primary winding 1 is a plurality of enameled round copper wires arranged in parallel as a layer and wound in a pagoda-like manner from the inside to the outside, and insulating paper is provided between two adjacent layers of enameled round copper wires, and a layer of primary high-voltage electrostatic screen 3 is wound on the outside of each level and separated from the enameled round copper wire by insulating paper, and the width of the primary high-voltage electrostatic screen 3 is greater than the width of the insulating paper between the corresponding layers;

[0031] As a preferred implementation provided by this embodiment, the primary high-voltage electrostatic screen 3 is a flexible composite paper with rubber strips on both sides and a whole semi-conductive crepe paper structure wrapped outside. The cross section of the primary high-voltage electrostatic screen 3 is flat in the middle and smooth on both sides.

[0032] like Figure 2-4 As shown, a primary insulating tube 17 is provided on the top of the voltage body, and a threaded nut 14 is provided in the front end of the primary insulating tube. The threaded nut 14 is connected to the primary high-voltage terminal 15. The threaded nut 14 is threadedly matched with the head bolt 13 and a silicone pad 16 is added to seal the corresponding fuse 12. The head bolt 13 has a plum blossom shape.

[0033] In an embodiment of the utility model, a primary grounding N terminal and a secondary wiring terminal 7 are provided on the secondary wiring platform 5 at the lower front side of the main insulator 4, a grounding terminal 9 is provided on the mounting base plate 6 and located at the rear end of the main insulator 4, and a secondary protective cover 8 is located on the secondary wiring platform for protecting the secondary wiring terminal.

[0034] In the embodiment of the utility model, the primary winding 1 is connected to the primary wiring insert 11, which is fixed on the primary insulating cylinder 17. The spring in the primary insulating cylinder 17 is fixed by screws, and the spring is in conflict with the rear end of the fuse 12. The primary wiring insert 11 is threadedly connected to the shielding net 10. Preferably, the shielding net 10 is made of a cylindrical iron wire mesh with an arc-shaped nut metal piece at the end and spot-welded.

[0035] The manufacturing process of the above-mentioned grounded voltage transformer with fuse is as follows: the primary winding 1 and the secondary winding are concentrically wound on an insulating frame, the primary winding 1 is wound in stages, and each stage of the winding is added with an insulating paper and a layer of electrostatic screen 3, the electrostatic screen 3 is wound outside each stage of the insulating paper, and the width of each stage of the electrostatic screen 3 is greater than the width of the insulating paper between the layers of this stage to shield the high-voltage electric field of this layer; after the primary and secondary windings are wound, they are sleeved on the iron core, and after the iron core is assembled, insulated and buffered, the voltage body 2 is formed, and then fixed in the casting mold, the shielding net 10 and the primary wiring insert 11 are connected, the nut 14 and the primary high-voltage terminal 15 and the primary wiring insert 11 are fixed, the secondary wiring is connected, the insulation distance is adjusted, and the main insulator 4 is formed by vacuum casting and curing of epoxy resin, and finally installed on a mounting base plate 6; the fuse 1 is sealed The primary insulating cylinder 17 of 2 is a horizontally arranged semi-cylindrical shape, which not only serves as the insulation of the fuse 12 to ensure a uniform electric field around it, but also serves as the main insulating transition piece; the primary seal adopts a threaded nut 14 and a silicone pad 16 in the middle of the head bolt 13 to be threadedly fixed to the front end of the primary insulating cylinder 17 to ensure reliable sealing and effective electrical contact of the primary high-voltage fuse, and has sufficient mechanical strength as a whole; the head bolt 13 is a metal bolt cast with epoxy resin, which has sufficient insulation, and the exposed part of the epoxy resin is plum blossom-shaped, which is convenient for manual installation or replacement of the fuse; during installation, there is no need to remove the primary wiring, and only the head bolt 13 needs to be unscrewed to inspect or replace the fuse 12, which is particularly convenient; the primary high-voltage terminal 15 is located at the top of the primary insulating cylinder 17, which increases the insulation distance of the primary high voltage to the ground.

[0036] When in use, first install the fuse into the primary insulating tube 17, then use the threaded nut 14 and the head bolt 1 to thread-seal the front end of the insulating tube, install the transformer on the switch cabinet in sequence according to the phase sequence distance through the installation base plate, finally connect the secondary line cable with the secondary socket, and install the secondary protective cover 14, and the voltage transformer assembly work is completed.

[0037] The effect of this implementation is that the product is small in size, full in function, easy to install, easy to maintain, with stable insulation and safe operation, which improves the design and manufacturing level of voltage transformers and switch cabinets.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A grounded voltage transformer with fuse, comprising a voltage body built into a main insulator, the voltage body comprising a primary winding, a secondary winding and an iron core, wherein the secondary winding and the primary winding are concentrically wound on the iron core from inside to outside, characterized in that: The primary winding is composed of multiple enameled round copper wires arranged in parallel as a layer and wound in a pyramid shape from the inside to the outside. Insulating paper is provided between two adjacent layers of enameled round copper wires. A primary high-voltage electrostatic screen is wrapped around the outside of each level and separated from the enameled round copper wire by insulating paper. The width of the primary high-voltage electrostatic screen is greater than the width of the insulating paper between the corresponding layers. A primary insulating cylinder is provided on the top of the voltage body. The front end of the primary insulating cylinder uses a head bolt and a silicone pad to seal the fuse in the primary insulating cylinder. A primary high-voltage terminal is provided on the primary insulating cylinder.

2. A grounding voltage transformer with fuse according to claim 1, characterized in that: The primary high-voltage electrostatic screen is a flexible composite paper with rubber strips on both sides and a whole semi-conductive crepe paper structure wrapped outside. The cross section of the primary high-voltage electrostatic screen is flat in the middle and smooth and convex on both sides.

3. A grounded voltage transformer with fuse according to claim 1, characterized in that: A threaded sleeve nut is arranged in the front end of the primary insulating cylinder, and the threaded sleeve nut is connected to the primary high-voltage terminal. The sealing bolt passes through the silicone pad and cooperates with the threaded sleeve nut to seal the fuse.

4. A grounding voltage transformer with fuse according to claim 1, characterized in that: The primary winding is connected to a primary wiring insert, which is fixed on a primary insulating cylinder. A spring in the primary insulating cylinder is fixed by a screw, and the spring contacts the rear end of the fuse. The primary wiring insert is threadedly connected to the shielding net.

5. A grounded voltage transformer with fuse according to claim 3, characterized in that: A primary grounding N terminal and a secondary wiring terminal are arranged on the secondary wiring platform at the lower front side of the main insulator. The grounding terminal is arranged at the rear end of the main insulator, and the secondary wiring terminal is located in the secondary protective cover.

6. A grounding voltage transformer with fuse according to claim 5, characterized in that: The main insulator is an integrated structure formed by casting a voltage body, a primary insulating cylinder, a primary high-voltage terminal, a screw sleeve nut, and a secondary wiring platform with epoxy resin, and the integrated structure is installed on the installation base plate as a whole.

7. A grounding voltage transformer with fuse according to claim 1 or 6, characterized in that: The main insulator is a rectangular parallelepiped structure, and the lower part of the four edges thereof is a missing-corner structure.

8. A grounding voltage transformer with fuse according to claim 4, characterized in that: The end of the shielding net is a circular arc nut metal piece, and the periphery of the circular arc nut metal piece is a cylindrical wire mesh and extends to one side.

9. A grounding voltage transformer with fuse according to claim 4, characterized in that: The shielding net is arranged in the epoxy resin of the primary insulating cylinder and is located at the outer periphery of the fuse.

10. A grounding voltage transformer with fuse according to claim 6, characterized in that: The head bolt is a metal bolt, the nut of which is plum blossom-shaped and is formed by vacuum casting of epoxy resin.

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