Voltage transformer with lightning protection structure

Abstract

The utility model discloses a voltage transformer with a lightning protection structure, which relates to the technical field of voltage transformers, aims to solve the technical problem that the lightning protection capability of the voltage transformer is weak, and comprises a voltage transformer main body, an insulating sleeve is arranged at the upper half part of the voltage transformer main body, and the insulating sleeve is of a wave-shaped structure. A metal shielding cover is arranged on the periphery of the voltage transformer body, a wave line conductor is arranged in a gap between the metal shielding cover and the insulating sleeve, a plurality of capacitance coupling lightning protection assemblies are arranged between the wave crest and the wave trough of the wave line conductor, and an inductance buffering assembly is embedded in the wave crest and wave trough conversion position of the wave line conductor. According to the utility model, through the wavy line appearance design of the wavy line conductor and the cooperative work of the capacitive coupling lightning protection assembly and the inductance buffer assembly, an omnibearing lightning protection system is formed and can be better integrated into the overall structure of the voltage transformer, so that the good electromagnetic compatibility of the lightning protection structure and the voltage transformer main body is ensured; and the interference on the normal electromagnetic coupling of the mutual inductor is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of voltage transformers, and more specifically to a voltage transformer with a lightning protection structure. Background Art

[0002] Voltage transformers are similar to transformers and are instruments used to transform voltage. However, the purpose of transformers to transform voltage is to facilitate the transmission of electrical energy, so the capacity is very large, and is generally calculated in kilovolt-amperes or megavolt-amperes. In actual use, when the power system operating environment is complex and lightning activity is frequent, strong lightning overvoltages will be transmitted to the voltage transformer through the transmission line. Existing lightning protection measures for voltage transformers mostly rely on traditional devices such as lightning arresters, but these conventional protection measures are often powerless in the face of high-amplitude lightning currents caused by direct lightning strikes and transient overvoltages caused by induced lightning. The huge energy generated by direct lightning strikes can instantly break through the insulation layer of the voltage transformer, causing serious faults such as winding short circuits and core burnouts, which completely damage the transformer and prevent it from working properly. In view of this, we propose a voltage transformer with a lightning protection structure. Utility Model Content

[0003] The purpose of the utility model is to overcome the deficiencies of the prior art, meet practical needs, and provide a voltage transformer with a lightning protection structure to solve the technical problem that the current voltage transformer has a weak lightning protection capability.

[0004] To solve the above technical problems, the utility model provides the following technical solutions: a voltage transformer with a lightning protection structure, comprising a voltage transformer body, an insulating sleeve is provided on the upper half of the voltage transformer body, the insulating sleeve is a wavy structure, a metal shielding cover is provided on the periphery of the voltage transformer body, an insulating bottom shell is installed at the bottom of the metal shielding cover, an insulating ring is fixed between the insulating bottom shell and the voltage transformer body, a wavy line conductor is provided in the gap between the metal shielding cover and the insulating sleeve, the wavy line conductor is also a wavy structure and corresponds to the outer periphery of the insulating sleeve, a plurality of equally spaced capacitive coupling lightning protection components are provided between the crests and troughs of the wavy line conductor, and an inductive buffer component is embedded in the transition between the crests and troughs of the wavy line conductor.

[0005] Preferably, the metal shielding cover is made of aluminum alloy, a non-contact gap is provided between the metal shielding cover and the voltage transformer body, and the bottom of the metal shielding cover is connected to the ground terminal of the voltage transformer body.

[0006] Preferably, the wave line conductor consists of a crest portion, a trough portion and a middle portion between the crest portion and the trough portion, and the crest portion and the trough portion are thickened.

[0007] Preferably, the capacitive coupling lightning protection assembly includes two metal plates, the two metal plates are arranged in parallel with each other, the metal plates are fixed to the wavy line conductor, and an insulating medium column is connected between the two metal plates.

[0008] Preferably, the inductor buffer component includes a ferrite core, which is embedded and fixed in the wavy conductor at the transition point between the peaks and troughs. The ferrite core is wound with multiple turns of enameled wire around its periphery, and the enameled wire consists of a conductor, an insulating layer, and multiple layers of insulating paint around the insulating layer.

[0009] Preferably, a plurality of sharp air ionization tips are arranged at the top of the wavy line conductor, the air ionization tips are made of stainless steel and the surface is silver-plated, and a copper flat strip is connected between the wavy line conductor and the primary winding grounding terminal of the voltage transformer body.

[0010] Compared with the prior art, the beneficial effects of the utility model are:

[0011] 1. The utility model forms an all-round lightning protection system through the coordinated work of multiple lightning protection structures. The wavy line conductor can efficiently attract and conduct lightning current at the moment of lightning strike due to its high conductivity copper alloy material and thickened design at the peaks and troughs, thereby reducing the impact of lightning current on other parts of the transformer. The capacitive coupling lightning protection component absorbs and stores the high-frequency overvoltage signal energy generated by lightning strikes through the capacitive coupling principle, effectively reducing the overvoltage amplitude. The inductive buffer component utilizes the high impedance characteristics of inductance to rapidly changing current to hinder the rapid rise of lightning current and play a buffering role, so that the lightning current passes through the lightning protection structure more smoothly. The air ionization tip guides lightning to discharge to the lightning protection structure in advance, reducing the probability of lightning directly hitting other parts of the voltage transformer. These structures cooperate with each other, greatly improving the lightning protection effect, effectively protecting the voltage transformer from damage by lightning strikes, and solving the problem of weak lightning protection ability of the voltage transformer.

[0012] 2. The utility model can also better integrate into the overall structure of the voltage transformer through the wavy line appearance design of the lightning protection structure based on the insulating sleeve, and has little impact on the normal electromagnetic performance of the transformer. In the complex power system environment, reasonable layout and material selection ensure good electromagnetic compatibility between the lightning protection structure and the voltage transformer body, reduce interference with the normal electromagnetic coupling of the transformer, and ensure that the transformer accurately converts the primary side voltage to the secondary side in proportion without affecting its normal operation.

[0013] 3. The utility model also adopts aluminum alloy material through the metal shielding cover, maintains a certain distance from the voltage transformer body through the insulating bracket, and is reliably connected to the grounding terminal of the voltage transformer body. This design can not only shield the electromagnetic pulse interference caused by lightning strikes to prevent it from affecting the internal circuit of the transformer, but also safely introduce the lightning current guided by the lightning protection structure into the earth to ensure the safety of the transformer and surrounding equipment. The wavy line conductor is connected to the primary winding grounding terminal of the voltage transformer body through a special conductive connector, avoiding the electromagnetic interference and connection failure hidden dangers caused by the external grounding wire, and improving the reliability of the lightning protection structure and the voltage transformer operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the structure of the utility model;

[0015] Figure 2 It is a schematic diagram of the split structure in the utility model;

[0016] Figure 3 It is a schematic diagram of a half-section structure of a wavy line conductor in the utility model;

[0017] Figure 4 It is a schematic diagram of the half-section structure of the inductor buffer component in the utility model.

[0018] Explanation of the numbers in the figure: 1. Voltage transformer body; 2. Insulating sleeve; 3. Metal shielding cover; 4. Insulating bottom shell; 5. Insulating ring; 6. Wave line conductor; 7. Capacitive coupling lightning protection assembly; 8. Inductor buffer assembly; 9. Copper flat strip; 10. Air ionization tip; 601. Crest part; 602. Valley part; 603. Middle part; 701. Metal plate; 702. Insulating medium column; 801. Ferrite core; 802. Enameled wire. DETAILED DESCRIPTION

[0019] like Figures 1 to 4 As shown, the utility model relates to a voltage transformer with a lightning protection structure, including a voltage transformer body 1, an insulating sleeve 2 is provided on the upper half of the voltage transformer body 1, and other structures are also provided inside the voltage transformer body 1. The voltage transformer body 1 can be directly purchased and obtained. This is the prior art, so it is not repeated here. The insulating sleeve 2 is a wavy structure, and a metal shielding cover 3 is provided on the periphery of the voltage transformer body 1. An insulating bottom shell 4 is installed at the bottom of the metal shielding cover 3, and an insulating ring body 5 is fixed between the insulating bottom shell 4 and the voltage transformer body 1. A wavy line conductor 6 is provided in the gap between the metal shielding cover 3 and the insulating sleeve 2. The wavy line conductor 6 is fixed to the position corresponding to the wavy line appearance of the insulating sleeve 2 by an insulating bracket and a clamp to ensure that the structure is stable and does not affect the normal operation and maintenance of the transformer. The wavy line conductor 6 is also a wavy structure and corresponds to the outer periphery of the insulating sleeve 2.

[0020] The structure of the wavy conductor 6:

[0021] Based on the wavy line appearance of the insulating sleeve 2, the wavy line part is designed as a conductor structure with special electrical properties. The wavy line conductor 6 consists of a crest portion 601, a trough portion 602 and a middle portion 603 between the crest portion 601 and the trough portion 602. A high-conductivity copper alloy material is used, and its conductivity is about 10% higher than that of ordinary copper materials, ensuring that lightning current can be quickly conducted at the moment of lightning strike. The crest portion 601 and the trough portion 602 of the wavy line conductor 6 are thickened, and the thickness is 30% greater than that of the middle portion 603 to enhance the local current carrying capacity.

[0022] Principle: When lightning strikes, the lightning current preferentially flows to the path with the least resistance. The wavy conductor 6 can efficiently attract and conduct the lightning current due to its good conductivity and unique thickening design, thus reducing the impact of the lightning current on other parts of the transformer.

[0023] The structure of the capacitive coupling lightning protection component 7:

[0024] A plurality of equally spaced capacitive coupling lightning protection components 7 are arranged between the crest and trough of the wavy conductor 6. Capacitive coupling lightning protection components 7 are installed at certain intervals (determined according to the size of the transformer and the voltage level, such as 5-10 cm) between the crest portion 601 and the trough portion 602 of the wavy conductor 6. The component is composed of two mutually parallel metal plates 701 and an insulating medium column 702 in the middle. The metal plate 701 is made of aluminum-zinc alloy, and the insulating medium column 702 is made of high-performance ceramic material, and its relative dielectric constant is 2-3 times higher than that of ordinary insulating materials.

[0025] Principle: The high-frequency overvoltage signal generated by lightning forms an electric field between the two metal plates 701 of the component through the principle of capacitive coupling. Part of the energy is absorbed by the capacitor and converted into electric field energy for storage, effectively reducing the overvoltage amplitude and protecting the internal circuit of the voltage transformer.

[0026] The structure of the inductor buffer component 8:

[0027] An inductor buffer component 8 is embedded at a specific position (such as a transition point between a peak and a trough) along the length direction of the wavy conductor 6. The inductor buffer component 8 includes a ferrite core 801. The ferrite core 801 has a high magnetic permeability. An enameled wire 802 is wound around the periphery of the ferrite core 801. The enameled wire 802 consists of a conductor, an insulating layer, and multiple layers of insulating paint around the insulating layer. The number of winding turns is adjusted according to actual needs to achieve a suitable inductance. The ferrite core 801 is specially formulated to have low hysteresis loss and high saturation magnetic induction intensity at high frequencies.

[0028] Principle: The instantaneous current change rate of lightning strike is large, and the inductor presents high impedance characteristics to the rapidly changing current, which can hinder the rapid rise of lightning current, play a buffering role, reduce the instantaneous impact of lightning current on the transformer, and make the lightning current pass through the lightning protection structure more smoothly.

[0029] In order to guide lightning, a plurality of sharp air ionization tips 10 are arranged at the top of the wavy conductor 6. The air ionization tips 10 are made of stainless steel and the surface is silver-plated to improve the conductivity and corrosion resistance. The length of the tip is preferably 5-10 mm and the angle is 30-45 degrees to ensure that the air can be effectively ionized under high electric field strength.

[0030] Principle: Before a lightning strike, the surrounding electric field strength increases, and the electric field strength near the air ionization tip 10 is concentrated, causing the air to be ionized to form a plasma conductive channel, which can guide the lightning to discharge to the lightning protection structure in advance and reduce the probability of lightning directly hitting other parts of the voltage transformer.

[0031] The metal shield 3 is connected to the ground:

[0032] The metal shielding cover 3 is based on the outside of the lightning protection structure of the wavy line. The metal shielding cover 3 is made of aluminum alloy with a thickness of 2-3 mm. It maintains a certain distance (such as 10-15 mm) from the voltage transformer body 1 through an insulating bracket. The bottom of the metal shielding cover 3 is reliably connected to the grounding terminal of the voltage transformer body 1. The grounding wire is a multi-strand copper stranded wire with a cross-sectional area determined according to the voltage level to ensure good grounding performance.

[0033] Principle: The metal shielding cover 3 can shield the electromagnetic pulse interference generated by lightning strikes, preventing it from affecting the internal circuit of the voltage transformer body 1. At the same time, the lightning current guided by the lightning protection structure is safely introduced into the ground to ensure the safety of the transformer and surrounding equipment.

[0034] Electrical connection of the above components: the wavy line conductor 6 is connected to the primary winding grounding terminal of the voltage transformer body 1 through a special conductive connector. The special conductive connector is preferably a copper flat strip 9, and is fixed with bolts to ensure that the lightning current can be smoothly introduced into the grounding system. The capacitor-coupled lightning protection component 7, the inductor buffer component 8, etc. are connected to the wavy line conductor 6 through welding or bolts to form an electrical path.

[0035] After the special conductive connector is connected, its function during a lightning strike is as follows: when struck by lightning, the overvoltage and high current generated by lightning will be quickly transmitted to the grounding terminal of the primary winding through the wavy conductor 6, and then discharged into the ground. This process actually shares the lightning energy that the voltage transformer body 1 may bear, and protects it from damage to the winding insulation or other components inside the transformer due to excessive overvoltage from lightning strikes.

[0036] And by connecting to the grounding terminal of the primary winding, an external grounding wire is avoided. The additional connection of the grounding lightning conductor may introduce new electromagnetic interference factors in the complex electromagnetic environment of the power system. One more grounding line may result in one more electromagnetic induction loop, which may lead to increased induced current and electromagnetic interference, affecting the normal operation of the voltage transformer. Each connection point is a potential fault point. Connecting the grounding lightning conductor separately will increase the number of connection points of metal conductive parts, thereby increasing the risk of poor grounding due to loose connections, corrosion and other reasons. By sharing the grounding path with the grounding terminal of the primary winding, this additional fault hazard can be reduced and the reliability of the entire lightning protection structure and the voltage transformer operation can be improved.

[0037] The contact part between the lightning protection structure and the voltage transformer body 1 is isolated by an insulating rubber pad to prevent electrical short circuit. At the same time, the electrical connection points of the lightning protection structure itself are insulated and packaged to improve the overall insulation performance.

[0038] Advantage Analysis

[0039] Efficient lightning protection: Various lightning protection structures work together to attract lightning current, buffer current impact, reduce overvoltage amplitude and guide early discharge, thus improving the lightning protection effect in all aspects.

[0040] Good compatibility: The special morphological structure is based on the original wavy line appearance design, which can be well integrated into the overall structure of the voltage transformer and has little effect on the normal electromagnetic performance of the transformer.

[0041] In terms of electromagnetic compatibility, avoid electromagnetic interference: Although the voltage transformer works in a strong electromagnetic environment, a reasonably designed lightning protection structure can achieve good electromagnetic compatibility with the voltage transformer body 1. For example, the layout and material selection of the wavy conductor 6 and its related components will take into account the minimum interference with the normal electromagnetic coupling of the transformer. In addition, the method of connecting to the grounding terminal of the primary winding will also be carefully designed to ensure that during the conduction of lightning current, no additional electromagnetic radiation will be generated to interfere with the electromagnetic induction process inside the transformer, thereby ensuring that the transformer accurately converts the primary side voltage to the secondary side in proportion.

[0042] The large current generated by the lightning strike at the moment may cause a certain amount of heat to be generated at the connection part. The wavy line conductor 6 is made of copper alloy material with high conductivity and good heat dissipation performance, which can quickly dissipate the heat generated by the lightning strike. At the same time, the wavy design of the wavy line conductor 6 makes the heat conduction and heat dissipation more uniform, avoiding local overheating and causing damage to the voltage transformer body 1.

[0043] The embodiments of the present invention disclose preferred embodiments, but are not limited thereto. A person skilled in the art can easily understand the spirit of the present invention based on the above embodiments and make different extensions and changes. However, as long as they do not deviate from the spirit of the present invention, they are all within the protection scope of the present invention.

Claims

1. A voltage transformer with a lightning protection structure, characterized in that: The invention comprises a voltage transformer body (1), wherein an insulating sleeve (2) is provided on the upper half of the voltage transformer body (1), wherein the insulating sleeve (2) is of a wavy structure, a metal shielding cover (3) is provided on the periphery of the voltage transformer body (1), an insulating bottom shell (4) is installed on the bottom of the metal shielding cover (3), an insulating ring body (5) is fixed between the insulating bottom shell (4) and the voltage transformer body (1), a wavy conductor (6) is provided in the gap between the metal shielding cover (3) and the insulating sleeve (2), wherein the wavy conductor (6) is also of a wavy structure and corresponds to the outer periphery of the insulating sleeve (2), a plurality of capacitor-coupled lightning protection components (7) distributed at equal intervals are provided between the crests and troughs of the wavy conductor (6), and an inductor buffer component (8) is embedded in the transition between the crests and troughs of the wavy conductor (6).

2. The voltage transformer of the lightning protection structure according to claim 1, characterized in that: The metal shielding cover (3) is made of aluminum alloy, a non-contact gap is provided between the metal shielding cover (3) and the voltage transformer body (1), and the bottom of the metal shielding cover (3) is connected to the grounding terminal of the voltage transformer body (1).

3. The voltage transformer of the lightning protection structure according to claim 2 is characterized in that: The wave line conductor (6) is composed of a crest portion (601), a trough portion (602), and an intermediate portion (603) between the crest portion (601) and the trough portion (602), and the crest portion (601) and the trough portion (602) are thickened.

4. The voltage transformer of the lightning protection structure according to claim 3 is characterized in that: The capacitive coupling lightning protection component (7) comprises two metal plates (701), the two metal plates (701) are arranged in parallel with each other, the metal plates (701) are fixed to the wavy line conductor (6), and an insulating medium column (702) is connected between the two metal plates (701).

5. The voltage transformer of the lightning protection structure according to claim 4, characterized in that: The inductor buffer component (8) comprises a ferrite core (801), the ferrite core (801) being embedded and fixed in a transition point between wave crests and wave troughs of a wavy conductor (6), a plurality of turns of enameled wire (802) being wound around the periphery of the ferrite core (801), the enameled wire (802) being composed of a conductor, an insulating layer, and multiple layers of insulating varnish around the insulating layer.

6. The voltage transformer of the lightning protection structure according to claim 5, characterized in that: A plurality of sharp air ionization tips (10) are arranged at the top of the wavy line conductor (6); the air ionization tips (10) are made of stainless steel and the surface is silver-plated; a copper flat strip (9) is connected between the wavy line conductor (6) and the primary winding grounding end of the voltage transformer body (1).

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