20kV indoor grounding type dry voltage transformer

Abstract

The utility model discloses a 20kV indoor grounding type dry voltage transformer for electric energy metering and relay protection in an electric power system. The 20kV indoor grounding type dry voltage transformer comprises a primary winding, a secondary winding, a rectangular iron core, an insulation protection body, a secondary outlet box and a mounting bottom plate, the secondary winding is wound on a core column of the rectangular iron core, the outer part of the cross section of the rectangular iron core is semicircular, and the inner part is trapezoidal, so that the cross section of the iron core is increased as much as possible in an effective space, and the overvoltage factor of a product and the anti-resonance capability of the iron core are improved; a certain insulation distance is reserved between the primary winding and the secondary winding and is filled with an insulation material, so that the insulation level of the primary high-voltage tail end is improved; and the insulation protection body encapsulates the transformer body and is molded by casting. In order to increase the creepage distance and the insulation strength between the two terminals along the surface, one protection wall is designed close to each of the primary high-voltage head end and the primary high-voltage tail end, and three protection umbrellas are designed in the middle; the secondary outlet box can facilitate wiring from two sides; the bottom is provided with a mounting bottom plate, and four mounting holes are designed in the bottom plate to facilitate mounting.

Description

Technical Field

[0001] The utility model relates to medium-voltage transformer equipment in an electric power system, in particular to a 20kV indoor grounding dry-type voltage transformer. Background Art

[0002] Voltage transformers are key signal transmission equipment for energy metering and relay protection in power systems. At present, most common medium-voltage grounded voltage transformers are semi-insulated structures and are used in three-phase power systems. Due to the low insulation level at the primary high-voltage end of the Y-type connection voltage transformer, it is not suitable to install a zero-sequence voltage protection device at the neutral point, and the anti-resonance ability is poor. Some long-term resonant overvoltage and overcurrent signals will cause serious damage to the transformer and cause accidents. Summary of the invention

[0003] In order to overcome the disadvantage that the existing semi-insulated structure voltage transformer cannot be equipped with a zero-sequence voltage protection device due to the low insulation level of the primary high voltage end, the utility model provides a 20kV indoor grounding dry-type voltage transformer. The utility model has a fully insulating structure, which not only improves the insulation level of the primary high voltage end and can be equipped with a zero-sequence voltage protection device, but also achieves an overvoltage resistance far exceeding the national standard requirements through the special design of the voltage core, and the electrical performance is more stable and reliable; in addition, the surface creepage distance between the primary high voltage head and the end is large, which is suitable for use in indoor heavily polluted areas.

[0004] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a 20kV indoor grounding dry-type voltage transformer, the secondary winding is wound on the core column of the iron core, the primary winding is wound on the outside of the secondary winding, the primary and secondary windings are filled with vacuum-cast insulating protection materials, the body of the device consisting of the primary high-voltage head end, the primary high-voltage terminal, the primary winding, the secondary winding, and the iron core is encapsulated by an insulating protection body, the surface creepage distance and insulation strength between the primary high-voltage head end and the primary high-voltage terminal, an insulating protection wall is designed near the two terminals of the primary high-voltage head end and the primary high-voltage terminal, and three trapezoidal cross-section long strip insulating protection umbrellas are designed in the middle.

[0005] The iron core is rectangular, and its cross section is divided into two parts, the outer part is semicircular, and the inner part is trapezoidal.

[0006] The insulating protective body is cast in a vacuum environment to imitate the shape of the device.

[0007] The cross section of the insulating protection wall is U-shaped.

[0008] The cross section of the insulating protective umbrella is trapezoidal.

[0009] The lead terminals of the secondary winding are centrally led out to a secondary junction box that can lead out wires from both sides.

[0010] A mounting base plate is arranged at the bottom of the transformer body, and four mounting holes are arranged on the mounting base plate.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: the improvement of the insulation level of the primary high voltage terminal satisfies the requirement that a zero-sequence voltage protection device can be installed at the neutral point of the Y-connected voltage transformer in a three-phase system, thereby achieving the purpose of protecting the voltage transformer; in addition, the special design of the rectangular core cross section improves the overvoltage factor, has a strong anti-ferromagnetic resonance capability, and has more stable and reliable electrical performance; between the primary high voltage head and the end, two protection walls and three long insulating protection umbrellas not only increase the surface creepage distance between the primary high voltage head and the end terminals, but also improve the insulation strength of the product, and will not cause flashover or breakdown between the two terminals. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is the front view of the utility model.

[0013] Figure 2 It is a side view of the utility model.

[0014] Figure 3 It is a top view of the utility model.

[0015] Markings in the figure: 1. Primary high voltage end, 2. Insulation protection wall, 3. Insulation protection umbrella, 4. Primary high voltage head end, 5. Primary winding, 6. Insulation protection body, 7. Secondary winding, 8. Iron core, 9. Secondary junction box, 10. Installation base plate. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. The components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0017] In order to overcome the disadvantage that the existing semi-insulated structure voltage transformer cannot be equipped with a zero-sequence voltage protection device due to the low insulation level of the primary high-voltage terminal, the utility model provides a 20kV indoor grounding dry-type voltage transformer. Figure 1 , Figure 2 , Figure 3In the figure, the secondary winding 7 is wound on the core column of the rectangular core 8. The cross-section of the rectangular core is composed of inner and outer parts. The outer part is semicircular and the inner part is trapezoidal. The cross-section of the core is increased as much as possible within the effective space, which improves the product overvoltage factor from 1.9 times of the national standard to more than 2.3 times. The anti-resonance ability of the core 8 far exceeds that of ordinary grounded voltage transformers; the primary winding 5 is wound on the outside of the secondary winding 7, and the vacuum-cast insulating protection material is filled between the primary and secondary windings to achieve a fully insulated structure. The primary high-voltage terminal 1 has the same high insulation level as the primary high-voltage head end 4; the device body composed of the primary high-voltage head end 4, the primary high-voltage terminal 1, the primary winding 5, the secondary winding 7, the core 8, etc. is encapsulated by an insulating protection body 6 cast in a vacuum environment that imitates the shape of the device body. In order to increase the creepage distance and insulation strength between the primary high voltage head end 4 and the primary high voltage end 1, a U-shaped insulating protection wall 2 is designed near each of the two terminals, and three trapezoidal long insulating protection umbrellas 3 are designed in the middle.

[0018] In order to facilitate secondary wiring, the lead terminals of the secondary winding 7 are centrally led out to the secondary junction box 9 where wires can be led out from both sides; in order to facilitate installation, a mounting base plate 10 is provided at the bottom of the utility model, and 4 mounting holes are designed on the mounting base plate 10 to facilitate installation and fixing of the product.

[0019] The improvement of the insulation level of the primary high-voltage terminal 1 satisfies the requirement that a zero-sequence voltage protection device can be installed at the neutral point of the Y-connected voltage transformer in the three-phase system, thereby achieving the purpose of protecting the voltage transformer; in addition, the special design of the rectangular core 8 cross section improves the overvoltage factor, has a strong anti-ferromagnetic resonance capability, and has more stable and reliable electrical performance; between the primary high-voltage head end 4 and the end, two insulating protection walls 3 and three long insulating protection umbrellas 2 not only increase the surface creepage distance between the primary high-voltage head and terminal terminals, but also improve the insulation strength of the product, and will not cause flashover or breakdown between the two terminals.

[0020] The above shows and describes the basic principle and main features of the utility model and the advantages of the utility model. Those skilled in the art should understand that the utility model is not limited by the above embodiments. The above embodiments and descriptions are only for explaining the principle of the utility model. Without departing from the spirit and scope of the utility model, the utility model may have various changes and improvements, which fall within the scope of the utility model to be protected. The scope of protection claimed by the utility model is defined by the attached claims and their equivalents.

Claims

1. A 20kV indoor grounding dry-type voltage transformer, characterized in that: The secondary winding (7) is wound on the core column of the iron core (8), and the primary winding (5) is wound on the outside of the secondary winding (7). The space between the primary and secondary windings is filled with vacuum-cast insulating protective material. The body composed of the primary high-voltage head end (4), the primary high-voltage terminal end (1), the primary winding (5), the secondary winding (7), and the iron core (8) is encapsulated by an insulating protective body (6). The surface creepage distance and insulation strength between the primary high-voltage head end (4) and the primary high-voltage terminal end (1) are improved. An insulating protective wall (2) is designed near the two terminals of the primary high-voltage head end (4) and the primary high-voltage terminal end (1), and three long insulating protective umbrellas (3) with trapezoidal cross-sections are designed in the middle.

2. A 20kV indoor grounding dry-type voltage transformer according to claim 1, characterized in that: The iron core (8) is rectangular, and its cross section is divided into two parts, an inner part and an outer part, wherein the outer part is semicircular and the inner part is trapezoidal.

3. A 20kV indoor grounding dry-type voltage transformer according to claim 1, characterized in that: The insulating protective body (6) is cast in a vacuum environment to imitate the shape of the device.

4. A 20kV indoor grounding dry-type voltage transformer according to claim 1, characterized in that: The cross-section of the insulating protection wall (2) is U-shaped.

5. A 20kV indoor grounding dry-type voltage transformer according to claim 1, characterized in that: The cross section of the insulating protective umbrella (3) is trapezoidal.

6. A 20kV indoor grounding dry-type voltage transformer according to claim 1, characterized in that: The lead terminals of the secondary winding (7) are centrally led out to a secondary junction box (9) that can output wires from both sides.

7. A 20kV indoor grounding dry-type voltage transformer according to claim 1, characterized in that: A mounting base plate (10) is arranged at the bottom of the transformer body, and four mounting holes are arranged on the mounting base plate (10).

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