A full-insulation voltage transformer for state grid

Abstract

The utility model relates to high pressure measuring equipment and relay protection device in power system especially relates to a full insulation voltage transformer for state grid. Including main insulator and the coil ware body and two primary conductive rods of being enclosed in main insulator, wherein the main insulator is cuboid, and the recess is equipped with in left and right side lower part, the top of main insulator is semicylinder structure, the front and back end surface of semicylinder structure is all inclined plane, and the two inclined planes all set up insulating column, and each insulating column top all inlays and sets up primary wiring terminal, two primary conductive rods are respectively contained in two insulating columns, and the upper end of two primary conductive rods is connected with two primary wiring terminal respectively, and the lower end all is connected with coil ware body, the front end bottom of main insulator is equipped with secondary wiring platform, and the secondary wiring platform inlays and sets up secondary wiring terminal. The utility model can guarantee high precision measurement, and has compact structure, easy installation, convenient maintenance, excellent insulation performance and the like.

Description

Technical Field

[0001] This utility model relates to high-voltage measuring equipment and relay protection devices in power systems, and particularly to a fully insulated voltage transformer for State Grid. Background Technology

[0002] Voltage transformers are indispensable key equipment in the State Grid power system, primarily used to convert high voltage to standard low voltage for use by measuring instruments, meters, relay protection devices, and control equipment. Traditional voltage transformers typically employ oil-immersed or gas-insulated structures. While these meet the State Grid's basic insulation and measurement requirements, they present several problems in practical applications, such as large size, complex installation, difficult maintenance, and unstable insulation performance. Furthermore, oil-immersed transformers are susceptible to oil leakage, and gas-insulated transformers may experience performance degradation due to changes in gas pressure.

[0003] With the State Grid's increasing demands for miniaturized, highly reliable, and easy-to-maintain equipment, traditional voltage transformers can no longer meet the needs of the modern power grid. Therefore, there is an urgent need for a new type of fully insulated voltage transformer for the State Grid, which can ensure high-precision measurement while featuring a compact structure, easy installation, convenient maintenance, and excellent insulation performance. Utility Model Content

[0004] To address the aforementioned problems, the purpose of this utility model is to provide a fully insulated voltage transformer for State Grid applications, thereby solving the problems of large size, complex installation and maintenance, and unstable insulation performance of existing voltage transformers.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0006] This utility model provides a fully insulated voltage transformer for State Grid use, including a main insulator, a coil body enclosed within the main insulator, and two primary conductive rods. The main insulator is cuboid in shape, with grooves on the lower parts of both its left and right sides. The top of the main insulator is a semi-cylindrical structure extending in the front-to-back direction, with both the front and rear ends of the semi-cylindrical structure being inclined surfaces. Two insulating posts are respectively arranged on the two inclined surfaces, and a primary terminal is embedded in the top of each insulating post. The two primary conductive rods are respectively housed within the two insulating posts, with the upper ends of the two primary conductive rods connected to the two primary terminals, and the lower ends of the two primary conductive rods connected to the coil body. A secondary terminal block is provided at the bottom of the front end of the main insulator, with a secondary terminal embedded within the secondary terminal block.

[0007] The coil body includes a primary winding, a secondary winding, an iron core, and an insulating frame. The secondary winding is wound around the iron core, and the leads of the secondary winding are connected to the secondary terminals. The primary winding is wound around the insulating frame, which is fitted over the secondary winding. The two leads of the primary winding are connected to the two primary conductive rods respectively. The iron core is insulated and buffered except for the part wound with the secondary winding, and then a shaped metal foil is added. A layer of semi-conductive crepe paper is half-folded and wrapped around the outside of the shaped metal foil. A layer of semi-conductive paint is brushed on both sides of the semi-conductive crepe paper to form a low-voltage shield.

[0008] The primary winding is a tower-shaped structure made of multiple enameled round copper wires arranged in a single turn and wound in multiple stages. The primary conductive rods are symmetrically fixed on the primary winding to form a primary winding assembly.

[0009] The insulating frame is an integral cylindrical structure made of glass wire and resin extrusion.

[0010] The two adjacent sides of the main insulator are both sloped; the groove is opened along the front-back direction of the main insulator, and the upper and lower edges of the groove are sloped.

[0011] The outer side of the insulating post is provided with multiple circular umbrella skirts at equal intervals along the height direction; the top of the insulating post is provided with a protruding structure, and the primary terminal is embedded in the protruding structure.

[0012] The secondary wiring platform is covered with a secondary wiring protective cover.

[0013] The main insulator is mounted on the mounting base plate, and the bottom of the main insulator is provided with a base plate mounting insert. The mounting base plate is connected to the base plate mounting insert by flat-head bolts.

[0014] The mounting base plate is equipped with a grounding terminal and a lifting ring.

[0015] The main insulator is an integral structure made of epoxy resin, cast together with the coil body and the two primary conductive rods.

[0016] This utility model has the following advantages and beneficial effects:

[0017] 1. Compact structure and excellent insulation performance: This utility model is made of epoxy resin by vacuum casting. The main insulator, primary and secondary windings, and iron core form an integrated structure, resulting in a compact structure and stable and reliable insulation. The primary terminal has sheds, and grooves are provided on both sides of the main insulator to effectively increase the creepage distance on the product surface. The upper part of the main insulator is semi-cylindrical, which facilitates the removal of dirt and effectively avoids the degradation of insulation performance caused by surface contamination, ensuring the safe operation of the equipment in high-voltage environments.

[0018] 2. Easy to install and maintain: The installation process of this utility model is simple. The current transformers are simply installed in the power system according to the phase sequence, which saves assembly time. Due to the use of epoxy resin vacuum casting and integrated fully insulated structure design, there is no need for oil or gas as an insulating medium, which avoids problems such as oil leakage and gas pressure changes, reduces maintenance workload and lowers operating costs.

[0019] 3. Strong adaptability and high reliability: This utility model can be installed in a variety of ways, such as pillar type and hanging type, which can meet the needs of different scenarios of State Grid and has strong adaptability; the fully insulated design reduces the impact of the external environment on the equipment, has higher mechanical strength and shock resistance, and can operate stably for a long time under complex working conditions. Attached Figure Description

[0020] Figure 1 This is a front view of a fully insulated voltage transformer for State Grid according to this utility model;

[0021] Figure 2 for Figure 1 The left view;

[0022] Figure 3 for Figure 2 CC section view;

[0023] Figure 4 for Figure 1 Top view.

[0024] In the diagram: 1 is the primary winding; 2 is the secondary winding; 3 is the iron core; 4 is the main insulator; 5 is the insulating frame; 6 is the mounting base plate; 7 is the secondary terminal block; 8 is the secondary wiring protective cover; 9 is the grounding terminal; 10 is the primary terminal block; 11 is the circular umbrella skirt; 12 is the insulating column; 13 is the secondary terminal block; 14 is the groove; 15 is the primary conductive rod; 16 is the base plate mounting insert; 17 is the flat head bolt. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] See Figure 1-4As shown, this utility model provides a fully insulated voltage transformer for State Grid use, including a main insulator 4, a coil body enclosed within the main insulator 4, and two primary conductive rods 15. The main insulator 4 is rectangular, with grooves 14 on the lower parts of its left and right sides. The top of the main insulator 4 is a semi-cylindrical structure extending in the front-to-back direction, with both the front and rear ends of the semi-cylindrical structure being inclined surfaces, which can reduce the overall weight and prevent the accumulation of dirt over time. Two insulating posts 12 are respectively provided on the two inclined surfaces, and a primary terminal 10 is embedded in the top of each insulating post 12. The two primary conductive rods 15 are respectively housed within the two insulating posts 12, with the upper ends of the two primary conductive rods 15 connected to the two primary terminals 10, and the lower ends of the two primary conductive rods 15 connected to the coil body. A secondary terminal block 7 is provided at the bottom of the front end of the main insulator 4, with a secondary terminal 13 embedded in the secondary terminal block 7.

[0027] See Figure 3 As shown in the embodiment of this utility model, the coil body includes a primary winding 1, a secondary winding 2, an iron core 3, and an insulating frame 5. The secondary winding 2 is wound around the iron core 3, and the leads of the secondary winding 2 are connected to the secondary terminal 13. The primary winding 1 is wound around the insulating frame 5, and the insulating frame 5 is fitted on the outside of the secondary winding 2. The two leads of the primary winding 1 are respectively connected to two primary conductive rods 15. In addition to the insulating buffer wrapping of the other parts of the iron core 3 where the secondary winding 2 is wound, a shaped metal foil is added on top. A layer of semi-conductive crepe paper is half-folded and wrapped on the outside of the shaped metal foil. Semi-conductive paint of appropriate width is brushed on both sides of the iron core 3 (outside the semi-conductive crepe paper) to form a low-voltage screen.

[0028] Furthermore, the primary winding 1 is a tower-shaped structure made of multiple enameled round copper wires arranged side by side in a single turn and wound in multiple stages. The primary conductive rods 15 are symmetrically fixed on the primary winding 1 to form the primary winding assembly. The insulating frame 5 is an integral cylindrical structure made of glass fiber and resin extrusion, with uniform thickness to ensure uniform distance between the primary and secondary insulation.

[0029] In this embodiment of the invention, the adjacent two sides of the main insulator 4 are both sloped to ensure uniform insulation distance. The groove 14 is opened along the front-back direction of the main insulator 4, and the upper and lower edges of the groove 14 are sloped to increase the creepage distance to ground.

[0030] In this embodiment of the invention, the outer side of the insulating post 12 is provided with a plurality of circular umbrella skirts 11 of the same size at equal intervals along the height direction; the top of the insulating post 12 is provided with a protruding structure, and the primary terminal 10 is embedded in the protruding structure.

[0031] Furthermore, the main insulator 4 is mounted on the mounting base plate 6, and a base plate mounting insert 16 is embedded in the bottom of the main insulator 4. The mounting base plate 6 is connected to the base plate mounting insert 16 by flat-head bolts 17. The flat-head bolts 17 serve as both connectors and electrical components. The mounting base plate 6 is equipped with bolts and nuts for use as grounding terminals 9, facilitating base plate grounding. The secondary wiring platform 7 is located at the lower front end of the main insulator 4, increasing the insulation distance between the primary wiring terminal 10 and ground. The secondary wiring platform 7 is equipped with a secondary wiring protective cover 8 for convenient secondary wiring connections.

[0032] Furthermore, the mounting base plate 6 is equipped with a grounding terminal 9 and a lifting ring.

[0033] Specifically, the main insulator 4 is an integral structure cast with epoxy resin, coil body and two primary conductive rods 15, to ensure excellent overall insulation performance.

[0034] The present invention provides a fully insulated voltage transformer for State Grid use, the preparation process of which is as follows:

[0035] 1) The secondary winding 2 is wound around the iron core 3 to form a secondary winding assembly;

[0036] 2) The primary winding 1 is wound on the insulating frame 5. The primary winding 1 is a tower-shaped structure made of multiple enameled round copper wires arranged in a single turn and wound in multiple stages. The primary conductive rod 15 is symmetrically fixed on the primary winding 1 to form a primary winding assembly.

[0037] 3) The primary winding assembly is fitted onto the outside of the secondary winding assembly. Then, the metal hose clamp is used to fasten the iron core 3 and the body clamp with positioning thread. After the iron core is insulated and buffered, a low-voltage shielding layer is wrapped around the iron core 3. After vacuum drying, it is fixed in the casting mold.

[0038] 4) Connect the primary winding assembly, secondary wiring and mounting base plate mounting insert 16, and adjust the insulation distance;

[0039] 5) Epoxy resin is vacuum cast and cured to form the main insulator 4;

[0040] 6) Install the mounting base plate 6 below the main insulator 4 to complete the assembly of the voltage transformer.

[0041] Specifically, the primary winding 1 is a tower-shaped structure made of multiple enameled round copper wires arranged in parallel as one turn and wound in multiple stages. The number of turns in each stage decreases from the inside to the outside. The number of turns in each layer of the same stage is the same. As the number of turns in each layer decreases, the electric field strength between layers decreases, and the electric field distribution becomes more uniform. The primary winding assembly is fitted onto the outside of the secondary winding assembly. Then, a metal hose clamp passes through the outside of the iron core 3 and between it and the insulation layer of the secondary winding 2. The iron core 3 and the clamping parts are fastened with positioning thread to ensure the stability of the iron core 3. After the iron core is insulated and buffered, a shaped copper foil or aluminum foil is added to the outside of the iron core 3. Then, a layer of semi-conductive corrugated paper is wrapped on the outside half-overlap. Then, a layer of semi-conductive paint of appropriate width is brushed on both sides of the iron core 3 to form a low-voltage shield. After vacuum drying, it is fixed in the casting mold. The main insulator 4 is a cuboid structure with a sloping transition between the top and the front and rear sides and adjacent sides. There are grooves 14 on the lower part of the left and right sides of the main insulator 4 to ensure uniform insulation distance. The primary terminals 10 are symmetrically arranged on the upper part of the main insulator 4 to ensure effective electrical contact with the primary high-voltage connection line and to ensure sufficient mechanical strength of the whole. The middle part of the two primary terminals 10 is designed as a semi-cylindrical shape, which not only reduces the weight of the casting body, but also facilitates the removal of surface dirt. The secondary terminal block 7 protrudes from the front side of the main insulator 4 and is located on the secondary terminal block 7. It is equipped with a secondary wiring protective cover 8 to facilitate secondary wiring. The insulating frame 5 is a cylindrical integrated structure made of glass fiber and resin extrusion to ensure uniform distance between primary and secondary insulation. The secondary terminal block 7 is located at the front end of the integrated structure and slightly downward, which increases the insulation distance between the primary terminals and the ground. The grounding terminal 9 is set on the mounting base plate 6 to facilitate grounding of the mounting base plate 6. The base plate mounting insert 16 is set below the main insulator 4 and is fixed to the mounting base plate 6 by flat head bolts 17, which optimizes the structural design and facilitates installation.

[0042] In use, first, according to the phase sequence distance, use the mounting base plate 6 of the voltage transformer to fix the voltage transformer on the ring main unit chassis. Then, connect the primary terminals of the product in parallel to the high voltage side of the line. Finally, connect the secondary cables on the low voltage side to the secondary terminals 13 and install the secondary wiring protective cover 8 to complete the assembly of the fully insulated voltage transformer.

[0043] This utility model provides a fully insulated voltage transformer for the State Grid, designed entirely in accordance with national standards and switchgear technical requirements. It employs a rolled iron core and utilizes the electromagnetic conversion principle to ensure that the secondary voltage accurately reflects changes in the primary voltage. It is suitable for voltage measurement and relay protection. This product boasts advantages such as comprehensive functionality, convenient installation, easy maintenance, stable insulation, and safe operation. It can be widely used in the State Grid's transmission and distribution network to ensure safe and reliable operation in high-voltage environments, while providing accurate voltage measurement signals. Its main applications include protection, monitoring, and metering.

[0044] The above description is merely an embodiment of this utility model and is not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, extensions, etc., made within the spirit and principles of this utility model are included within the scope of protection of this utility model.

Claims

1. A fully insulated voltage transformer for State Grid applications, characterized in that, The device includes a main insulator (4), a coil body enclosed within the main insulator (4), and two primary conductive rods (15). The main insulator (4) is rectangular, with grooves (14) on the lower part of both the left and right sides. The top of the main insulator (4) is a semi-cylindrical structure extending in the front-to-back direction. The front and rear ends of the semi-cylindrical structure are both inclined surfaces, with two insulating posts (12) on each of the two inclined surfaces. Each insulating post (12) has a primary terminal (10) embedded in its top. The two primary conductive rods (15) are respectively housed within the two insulating posts (12). The upper ends of the two primary conductive rods (15) are connected to the two primary terminals (10), and the lower ends of the two primary conductive rods (15) are connected to the coil body. A secondary terminal block (7) is provided at the bottom of the front end of the main insulator (4), with a secondary terminal (13) embedded in the secondary terminal block (7).

2. The State Grid fully insulated voltage transformer according to claim 1, characterized in that, The coil body includes a primary winding (1), a secondary winding (2), an iron core (3), and an insulating frame (5). The secondary winding (2) is wound around the iron core (3), and the lead wire of the secondary winding (2) is connected to the secondary terminal (13). The primary winding (1) is wound around the insulating frame (5), and the insulating frame (5) is fitted on the outside of the secondary winding (2). The two leads of the primary winding (1) are respectively connected to the two primary conductive rods (15). The iron core (3) is insulated and buffered in addition to the part wound around the secondary winding (2), and then a shaped metal foil is added. A layer of semi-conductive crepe paper is half-folded and wrapped on the outside of the shaped metal foil. A layer of semi-conductive paint is brushed on both sides of the semi-conductive crepe paper to form a low-voltage screen.

3. The State Grid fully insulated voltage transformer according to claim 2, characterized in that, The primary winding (1) is a tower-shaped structure made of multiple enameled round copper wires arranged in a single turn and wound in multiple stages. The primary conductive rod (15) is symmetrically fixed on the primary winding (1) to form a primary winding assembly.

4. The State Grid fully insulated voltage transformer according to claim 2, characterized in that, The insulating frame (5) is an integral cylindrical structure made of glass wire and resin extrusion.

5. The State Grid fully insulated voltage transformer according to claim 1, characterized in that, The two adjacent sides of the main insulator (4) are both sloped transitions; the groove (14) is opened along the front-back direction of the main insulator (4), and the upper and lower edges of the groove (14) are sloped transitions.

6. The State Grid fully insulated voltage transformer according to claim 1, characterized in that, The outer side of the insulating column (12) is provided with a plurality of circular umbrella skirts (11) at equal intervals along the height direction; the top of the insulating column (12) is provided with a protruding structure, and the primary terminal (10) is embedded in the protruding structure.

7. The State Grid fully insulated voltage transformer according to claim 1, characterized in that, The secondary wiring platform (7) is covered with a secondary wiring protective cover (8).

8. The State Grid fully insulated voltage transformer according to claim 1, characterized in that, The main insulator (4) is mounted on the mounting base plate (6). The bottom of the main insulator (4) is provided with a base plate mounting insert (16). The mounting base plate (6) is connected to the base plate mounting insert (16) by a flat-head bolt (17).

9. The State Grid fully insulated voltage transformer according to claim 8, characterized in that, The mounting base plate (6) is provided with a grounding terminal (9) and a lifting ring.

10. The State Grid fully insulated voltage transformer according to claim 1, characterized in that, The main insulator (4) is an integral structure formed by casting epoxy resin with the coil body and the two primary conductive rods (15).

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