A harmonic eliminator for electromagnetic voltage transformers

Abstract

The utility model discloses a kind of harmonic absorbers for electromagnetic voltage transformer, including protective cover and nonlinear resistance sheet, nonlinear resistance sheet is fixed in protective cover, further include ground side conducting plate, high voltage side conducting plate and pressing plate, the protective cover is made of metal, and one side has opening, nonlinear resistance sheet is cuboid structure, high voltage side conducting plate and ground side conducting plate are respectively located nonlinear resistance sheet upper portion and lower portion, and are fixed in protective cover by pressing plate, high voltage wiring stud is equipped on pressing plate, ground stud is equipped on protective cover. The utility model designs nonlinear resistance sheet as cuboid, greatly reduce space occupancy, adapt to outdoor narrow installation environment, and reduce contact resistance by aluminum plate conducting plate, reduce additional heating, ground stud is equipped on protective cover, it is convenient to ground directly, with the characteristics of simple structure, easy to install, safe and reliable.

Description

Technical Field

[0001] This utility model relates to a harmonic suppressor for electromagnetic voltage transformers, which is particularly suitable for electromagnetic voltage transformers configured with outdoor pole-mounted switches. Background Technology

[0002] Electromagnetic voltage transformers are prone to resonance during operation, and harmonic suppressors are key devices for solving this problem. Existing harmonic suppressors for electromagnetic voltage transformers are mostly cylindrical in structure, with their nonlinear resistive elements designed in a cylindrical shape. One end is grounded, and the other end is connected to the neutral point of the three-phase voltage transformer. Harmony suppression is achieved by consuming the electrical energy of the resonant overcurrent.

[0003] However, existing cylindrical harmonic suppressors require unobstructed space within 5cm of the high-voltage end to meet insulation and heat dissipation requirements, resulting in a large overall footprint. For outdoor pole-mounted switches with three-phase voltage transformers, existing cylindrical harmonic suppressors are difficult to adapt due to limited installation space, posing a significant space requirement. Furthermore, the nonlinear resistor itself generates heat during operation, and current technology lacks auxiliary heat dissipation measures, leading to poor heat dissipation and inconvenient grounding connections, making it unsuitable for rapid outdoor installation. Summary of the Invention

[0004] In view of the defects and problems of existing technologies, this utility model provides a harmonic suppressor for electromagnetic voltage transformers. The purpose is to solve the problems of existing harmonic suppressors occupying a large space and being unsuitable for outdoor pole-mounted switches. It has the characteristics of small size, small space occupation, good heat dissipation and convenient grounding.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A harmonic suppressor for an electromagnetic voltage transformer includes a protective cover and a nonlinear resistor sheet, the nonlinear resistor sheet being fixed inside the protective cover. It also includes a grounding conductive plate, a high-voltage conductive plate, and a pressure plate. The protective cover is made of metal and has an opening on one side. The nonlinear resistor sheet has a cuboid structure. The high-voltage conductive plate and the grounding conductive plate are located above and below the nonlinear resistor sheet, respectively, and are fixed inside the protective cover by the pressure plate. The pressure plate is provided with a high-voltage wiring stud, and the protective cover is provided with a grounding stud.

[0007] The advantage is that there are at least two nonlinear resistors stacked in contact. The cuboid structure of the nonlinear resistor can effectively reduce the geometric dimensions in one direction and facilitate the adjustment of the series resistance value under the same cross-sectional area and safety distance.

[0008] Another advantage is that both the grounding side conductive plate and the high-voltage side conductive plate are made of aluminum plates, and both have flanges around the perimeter for limiting the nonlinear resistor pieces. The flexibility of the aluminum plate reduces the resistance of the contact surface and reduces additional heat generation. The flange design can effectively limit the displacement of the nonlinear resistor pieces, improve structural stability, and avoid poor contact caused by vibration, etc.

[0009] Another advantage is that the grounding side conductive plate is fixed to the inner wall of the protective cover by nuts, the nonlinear resistor is placed on the grounding side conductive plate, and the high-voltage side conductive plate is set on the top of the nonlinear resistor. The high-voltage side conductive plate is also set on the top of the high-voltage side conductive plate and is fixed to the inner wall of the protective cover by flat washers, spring washers and bolts. This facilitates installation and subsequent maintenance and disassembly, while ensuring tight contact between the components and reducing the risk of loosening.

[0010] Another advantage is that the pressure plate has flanges on both sides and is fixed to the inner wall of the protective cover by insulating bolts. The flanges on both sides can help limit the movement, and together with the tightening effect of the insulating bolts, ensure the overall stability of the equipment and prevent loose parts from causing poor contact.

[0011] Another advantage is that the protective cover has a rectangular structure with outward flanges on all four sides, facilitating external grounding and ensuring electrical continuity of the equipment. The outward flanges also enhance the structural strength of the protective cover and make it easy to fix. The heat generated by the nonlinear resistor is dissipated into the air over a large area through the protective cover, preventing damage from overheating.

[0012] With the above structure, this invention occupies less space. The nonlinear resistor is designed as a cuboid, which significantly reduces the space occupied in one direction compared to the traditional cylindrical structure, making it more suitable for the confined installation environment of outdoor pole-mounted switches. Furthermore, the high-voltage side conductive plate and the grounding side conductive plate are in contact with the upper and lower parts of the nonlinear resistor, ensuring good electrical connection at the contact surfaces and reducing additional heat generation. A grounding stud is provided on the outside of the protective cover for easy direct grounding. The overall assembly process is simple and suitable for rapid outdoor installation. Attached Figure Description

[0013] Figure 1 This is a three-dimensional assembly diagram of the present invention;

[0014] Figure 2 yes Figure 1 Main view;

[0015] Figure 3 yes Figure 2 Sectional view along axis AA;

[0016] Figure 4 yes Figure 2 BB-direction sectional view.

[0017] In the diagram: 1-protective cover; 2-grounding side conductive plate; 3-nut; 4-nonlinear resistor; 5-flat washer; 6-spring washer; 7-insulating bolt; 8-high voltage terminal; 9-pressure plate; 10-high voltage side conductive plate; 11-bolt; 12-grounding stud. Detailed Implementation

[0018] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Example: See Figures 1-4 As shown, a harmonic suppressor for an electromagnetic voltage transformer includes a protective cover 1, a nonlinear resistor 4, a grounding-side conductive plate 2, a high-voltage-side conductive plate 10, and a pressure plate 9. The protective cover 1 is a rectangular structure made of metal with an opening on one side. During installation, the entire protective cover 1 is placed on the neutral point of the electromagnetic voltage transformer through the opening and fixed to the outdoor pole-mounted switch. In this embodiment, both sides of the protective cover 1 have grounding studs 12 for easy direct grounding. The overall assembly process is simple and suitable for rapid outdoor installation. Furthermore, the outer flanges on all four sides greatly improve the convenience of grounding operations and ensure grounding reliability. The outer flanges on all four sides of the protective cover 1 can form a shield, preventing outdoor rainwater and dust from entering the interior, protecting core components such as the nonlinear resistor 4 and the conductive plate, and extending the service life of the equipment. The nonlinear resistor 4 has a cuboid structure, which significantly reduces the space occupied in one direction under the same cross-section, making it more suitable for the confined installation environment of outdoor pole-mounted switches.

[0021] See Figure 1 , Figure 3 , Figure 4As shown, there are two nonlinear resistor sheets 4. Of course, more can be stacked and made in contact as needed. In this embodiment, after the two nonlinear resistor sheets 4 are stacked, they can withstand a larger leakage current in a low-resistance state, consume overvoltage energy more efficiently, and enhance the overvoltage suppression capability of the harmonic suppressor. The contact surfaces of the two nonlinear resistor sheets 4 are metallized to ensure sufficient electrical continuity.

[0022] See Figures 1-4 As shown, the high-voltage side conductive plate 10 and the grounding side conductive plate 2 are located on the upper and lower parts of the nonlinear resistor sheet 4, respectively, and are fixed inside the protective cover 1 by the pressure plate 9. The pressure plate 9 is provided with a high-voltage wiring stud 8, and the protective cover 1 is provided with a grounding stud 12.

[0023] See Figures 1-4 As shown, both the grounding-side conductive plate 2 and the high-voltage-side conductive plate 10 are made of aluminum plates, and both have flanges around their perimeter for limiting the nonlinear resistor 4. In this embodiment, the aluminum plate has good conductivity, and its flexibility allows the contact surface between the grounding-side conductive plate 2 and the protective cover 1 to fit more tightly. The nonlinear resistor 4 directly contacts the protective cover 1, improving contact resistance and avoiding additional heat generation. When the nonlinear resistor 4 in the harmonic suppressor enters a low-resistance discharge state due to overvoltage, the aluminum plate conductive plate needs to act as a current channel to smoothly guide the discharge current into the grounding-side conductive plate 2. Its low contact resistance characteristic can avoid additional power consumption and heat generation when a large current passes through, ensuring the stable operation of the harmonic suppressor under overvoltage conditions and preventing the overall performance from being affected or causing a malfunction due to overheating of the conductive plate. The grounding side conductive plate 2 has flanges around its perimeter that fit against the outer wall of the nonlinear resistor sheet 4, forming a circumferential limit on the nonlinear resistor sheet 4. Combined with the overall clamping of the insulating bolts 7, this prevents the nonlinear resistor sheet 4 from shifting due to vibration, temperature changes, etc. during operation, ensuring that the contact surface between the nonlinear resistor sheet 4 and the conductive plates on both sides is always in stable contact, and avoiding fluctuations in contact resistance that could affect performance.

[0024] See Figures 1-4 As shown, the grounding side conductive plate 2 is fixed to the inner wall of the protective cover 1 by the nut 3. The nonlinear resistor 4 is placed on the grounding side conductive plate 2, and a high-voltage side conductive plate 10 is set on the upper part of the nonlinear resistor 4. A pressure plate 9 is set on the upper part of the high-voltage side conductive plate 10 and is fixed to the inner wall of the protective cover 1 by the flat washer 5, the spring washer 6 and the bolt 11. In this embodiment, the nonlinear resistor 4 is fixed to the inner wall of the protective cover 1 by the insulating bolt 7 and the pressure plate 9, and the components are pressed and fixed to form a nonlinear resistance circuit from the high-voltage terminal stud 8 to the grounding stud 12 to realize the harmonic elimination function.

[0025] See Figures 1-4 As shown, the pressure plate 9 has flanges on both sides, which not only improves strength but also makes it easier to limit and fix the high-voltage side conductive plate 10, facilitating installation.

[0026] See Figures 1-4 As shown, the heat from the nonlinear resistor 4 can be dissipated into the outside air through the expanded area of ​​the protective cover 1, preventing damage due to overheating. However, the nonlinear resistor 4 itself has a small heat dissipation area and poor airflow around it, both of which are detrimental to heat dissipation.

[0027] See Figure 1 , Figure 3 , Figure 4 As shown, when the voltage transformer is operating normally, the system voltage is stable with no significant overvoltage. At this time, the series-connected nonlinear resistor 4 exhibits high resistance, and the current flowing through it is minimal; the harmonic suppressor does not affect the normal operation of the transformer. When resonance occurs, under the influence of overvoltage, the resistance of the nonlinear resistor 4 decreases sharply as the voltage increases, changing from a high-resistance state to a low-resistance state, forming a circuit. As the resonant current is consumed, the overvoltage disappears, and the system voltage returns to normal. When the voltage of the nonlinear resistor 4 decreases, its resistance automatically returns to a high-resistance state, and the current flowing through it decreases again to approximately an open circuit. The harmonic suppressor returns to standby mode and does not affect the normal operation of the transformer.

[0028] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the above embodiments should be considered exemplary and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0029] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A harmonic suppressor for an electromagnetic voltage transformer, comprising a protective cover (1) and a nonlinear resistor (4), wherein the nonlinear resistor (4) is fixed inside the protective cover (1), characterized in that, It also includes a grounding side conductive plate (2), a high voltage side conductive plate (10), and a pressure plate (9). The protective cover (1) is made of metal and has an opening on one side. The nonlinear resistor (4) has a cuboid structure. The high voltage side conductive plate (10) and the grounding side conductive plate (2) are located on the upper and lower parts of the nonlinear resistor (4), respectively, and are fixed inside the protective cover (1) by the pressure plate (9). The pressure plate (9) is provided with a high voltage wiring stud (8), and the protective cover (1) is provided with a grounding stud (12).

2. The harmonic suppressor for an electromagnetic voltage transformer according to claim 1, characterized in that, The nonlinear resistor sheet (4) has at least two pieces, which are stacked in contact.

3. A harmonic suppressor for an electromagnetic voltage transformer according to claim 1, characterized in that, Both the grounding side conductive plate (2) and the high voltage side conductive plate (10) are made of aluminum plates, and both have flanges around the perimeter for limiting the nonlinear resistor sheet (4).

4. A harmonic suppressor for an electromagnetic voltage transformer according to claim 1, characterized in that, The grounding side conductive plate (2) is fixed to the inner wall of the protective cover (1) by a nut (3). The nonlinear resistor (4) is placed on the grounding side conductive plate (2), and a high voltage side conductive plate (10) is set on the upper part of the nonlinear resistor (4). A pressure plate (9) is set on the upper part of the high voltage side conductive plate (10), and it is fixed to the inner wall of the protective cover (1) by a flat washer (5), a spring washer (6) and a bolt (11).

5. A harmonic suppressor for an electromagnetic voltage transformer according to claim 1, characterized in that, The pressure plate (9) has flanges on both sides and is fixed to the inner wall of the protective cover (1) by insulating bolts (7).

6. A harmonic suppressor for an electromagnetic voltage transformer according to claim 1, characterized in that, The protective cover (1) has a rectangular structure and has outer flanges on all four sides.

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