Improved coil lead structure

Abstract

The utility model discloses an improved coil lead structure, specifically relates to transformer coil technical field, and the lower yoke post is fixedly connected with three vertical yoke posts at the top, the top of vertical yoke post is fixedly connected with upper yoke post, and the outside of vertical yoke post is provided with high low voltage coil, and the inside fixed connection of high low voltage coil has inner lead, and the inside fixed connection of high low voltage coil has outer lead, and the rear side fixed connection of three inner leads has D connection copper bar, and the support mechanism is arranged on the lower yoke post and upper yoke post. The utility model discloses by with D connection copper bar connection position is from in the upper portion of lead downward adjustment, adjustment is in the middle part of lead, and low voltage insulator is above lead, and D connection lead or Y connection seal line is placed in the middle part of head lead, and the height of head lead is reduced, and when the middle part outlet wire, the length of outlet wire vertical row is also shortened accordingly, thereby reduces the copper bar use amount, and the cost is reduced, and the function of reducing copper bar length is realized.

Description

Technical Field

[0001] This utility model relates to the field of transformer coil technology, and more specifically, to an improved coil lead structure. Background Technology

[0002] With the development of my country's power industry, the power supply has been increasing year by year, and power transformers have gradually developed towards high voltage and large capacity. The transformers are very large and difficult to install. D indicates delta connection. D-connection leads are a structure in which the transformer coil adopts delta connection. In the existing technology, D-connection leads are located on the upper part of the insulator, and the lead height is high, which leads to an increase in the height of the transformer casing.

[0003] In common coil lead structures, when a delta connection is used, the design lacks the function of effectively reducing the length of the copper busbar. This results in the height of the coil tail lead being typically higher than the low-voltage clamp by the width of the copper busbar. At the same time, the upper end of the D-connector lead or Y-connector sealing wire is flush with the upper end of the tail lead, causing the overall copper busbar to be installed at a high position. This high arrangement will directly lead to an increase in the vertical length of the outgoing wires during the outgoing process, resulting in increased product costs.

[0004] In summary, the height of the coil tail lead often exceeds the width of one copper busbar of the low-voltage upper clamp. At the same time, the D-connector lead or Y-connector sealing wire is flush with the upper end of the tail lead, resulting in the overall installation position of the copper busbar being relatively high. This high-position arrangement forces an increase in the length of the vertical output line. In order to reduce costs, it is necessary to solve the problem of excessive copper busbar length. Utility Model Content

[0005] The present invention provides an improved coil lead structure, which aims to solve the problem that the height of the existing coil tail lead often exceeds the width of one copper busbar of the low-voltage upper clamp, and the problem of excessive copper busbar length needs to be solved.

[0006] To achieve the above objectives, this utility model provides the following technical solution: It includes a lower yoke column, three vertical yoke columns fixedly connected to the top of the lower yoke column, an upper yoke column fixedly connected to the top of the vertical yoke column, high and low voltage coils arranged on the outer side of the vertical yoke column, inner leads fixedly connected inside the high and low voltage coils, outer leads fixedly connected inside the high and low voltage coils, and D-connected copper busbars fixedly connected to the rear side of the three inner leads. Support mechanisms are provided on the lower and upper yoke columns for supporting the installation of various components. An insulation mechanism is provided on the upper yoke column to prevent the transmission of electrical energy.

[0007] In a preferred embodiment, the support mechanism includes an auxiliary support component and a fixing component. The auxiliary support component is used to support the bottom of the high and low voltage coils, and the fixing component is used to install and support the insulation mechanism.

[0008] In a preferred embodiment, the auxiliary support assembly includes lower clamps fixedly connected to the front and rear sides of the lower yoke and two bases fixedly connected to the bottom of the lower clamps.

[0009] In a preferred embodiment, the fixing assembly includes a low-pressure upper clamp fixedly connected to the front side of the upper yoke and a high-pressure upper clamp fixedly connected to the rear side of the upper yoke.

[0010] In a preferred embodiment, the insulation mechanism includes a low-voltage insulation component and a high-voltage insulation component, wherein the low-voltage insulation component is used to prevent the transmission of low-voltage electrical energy and the high-voltage insulation component is used to prevent the transmission of high-voltage electrical energy.

[0011] In a preferred embodiment, the low-voltage insulation assembly includes two first L-shaped fixing plates fixedly connected to the top of the low-voltage upper clamp, and a low-voltage insulator fixedly connected to the front side of the first L-shaped fixing plates.

[0012] In a preferred embodiment, the high-voltage insulation assembly includes three second L-shaped fixing plates fixedly connected to the top of the high-voltage clamp, and a high-voltage insulator fixedly connected to the rear side of the second L-shaped fixing plates.

[0013] The beneficial effects of this utility model are as follows:

[0014] This invention optimizes the structural design by adjusting the connection position of the D-connector copper busbar to the middle of the lead wire, significantly reducing the height of the first and last lead wires, and shortening the length of the vertical output line. This directly reduces the amount of copper busbar material used, effectively reducing production costs and achieving cost control advantages.

[0015] The layout of this utility model ensures that the low-voltage insulator is stably positioned above the lead wire, enhancing the safety and reliability of electrical insulation. The design of placing the D-connector lead wire or Y-connector sealing wire in the middle of the beginning and end lead wires further optimizes space utilization, improves the compactness and stability of the overall structure, and achieves the advantage of performance optimization. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0017] Figure 2 This is a schematic diagram of the overall cross-sectional structure of this utility model.

[0018] Figure 3 This is a schematic diagram of the yoke structure of this utility model.

[0019] Figure 4 This is a schematic diagram of the high and low voltage coil structure of this utility model.

[0020] Figure 5 This is a schematic diagram of the insulator structure of this utility model.

[0021] The attached diagram is labeled as follows: 1. Lower yoke post; 11. Vertical yoke post; 12. Upper yoke post; 13. High and low voltage coils; 14. Inner lead; 15. Outer lead; 16. D-connector copper busbar; 211. Lower clamp; 212. Base; 221. Low voltage upper clamp; 222. High voltage upper clamp; 311. First L-shaped fixing plate; 312. Low voltage insulator; 321. Second L-shaped fixing plate; 322. High voltage insulator. Detailed Implementation

[0022] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0023] With the rapid development of my country's economy and the continuous acceleration of industrialization, the demand for electricity, as the core energy supporting the operation of society, has shown a continuous upward trend. Data from the National Energy Administration shows that in the past decade, my country's annual power supply has steadily increased at an average annual rate of more than 5%. In 2024, the total power supply in the country exceeded 9 trillion kilowatt-hours, more than doubling compared to 2014. This large-scale increase in electricity demand has not only promoted the expansion and upgrading of the power generation side (such as hydropower, thermal power, wind power, and photovoltaic power), but also posed unprecedented technical challenges to the core equipment in the power transmission and transformation links—power transformers—prompting them to evolve towards higher voltage and larger capacity.

[0024] As a key device in the power system for voltage transformation and power transmission, the technical parameters of power transformers are closely related to the scale and voltage level of the power network. In my country, with the in-depth advancement of cross-regional power transmission projects such as the West-to-East Power Transmission and the North-to-South Power Transmission, ultra-high voltage power transmission technology (such as 1000kV AC and ±800kV DC) has become the core means to solve the problem of reverse distribution of energy and load centers. The realization of ultra-high voltage power transmission is inseparable from the matching high-voltage and large-capacity transformers.

[0025] From a technical perspective, the increase in transmission voltage level and the increase in transformer capacity are mutually reinforcing. According to the transmission power formula P=√3UIcosφ (where U is the line voltage, I is the line current, and cosφ is the power factor), under the condition of a certain transmission power, increasing the voltage level can significantly reduce the current, thereby reducing the loss of transmission lines (loss is proportional to the square of the current). Therefore, in order to improve transmission efficiency and reduce line investment, the grid voltage level has been gradually upgraded from 220kV and 500kV to 1000kV, and the rated voltage of transformers has also crossed from 110kV and 220kV to 500kV and 1000kV.

[0026] At the same time, the capacity of transformers is also increasing. Taking 500kV transformers as an example, in the 1990s, the main models in my country had a capacity of 120MVA, while the current main transformer capacity of UHV substations has reached more than 3000MVA. The application of large-capacity transformers can reduce the number of equipment in substations, simplify the power grid structure, and improve the stability and economy of power transmission. For example, the transmission capacity of a 3000MVA UHV transformer is equivalent to the total of dozens of traditional 110kV transformers, which greatly reduces the equipment footprint and operation and maintenance costs.

[0027] The trend towards higher voltage and larger capacity transformers is driven by a significant increase in their physical size. This change is primarily determined by the design requirements of the following core components:

[0028] First is the iron core. The iron core of a transformer is the core of the magnetic circuit. Its cross-sectional area is proportional to the rated capacity (the larger the capacity, the greater the required magnetic flux, and the larger the cross-sectional area of ​​the iron core). For large-capacity transformers, the iron core diameter often exceeds 3 meters, the height can reach 5-6 meters, and the weight of a single unit can reach tens of tons. In order to reduce iron loss, the iron core is usually made of high-permeability silicon steel sheets. The stacking process of large-size iron cores not only requires higher processing precision, but also directly increases the overall volume.

[0029] Secondly, there is the winding. The winding is the key to the voltage transformation of the transformer. High voltage levels require the winding to have a thicker insulation layer (such as the insulation distance of a 1000kV transformer can be several meters), while large capacity requires more winding turns and a larger conductor cross-sectional area. For example, the low voltage winding of an ultra-high voltage transformer usually uses multiple flat conductors wound in parallel, and the cross-sectional area of ​​a single conductor can be more than 100mm². The diameter and height of the winding are thus greatly increased.

[0030] In addition, the size of auxiliary components such as oil tanks and cooling systems has also increased. The oil tanks of high-voltage, high-capacity transformers need to accommodate a larger volume of insulating oil (the oil volume of some models exceeds 100 tons), and the number and size of cooling systems (such as forced oil circulation air coolers) also need to be increased to meet heat dissipation requirements, further increasing the overall size of the equipment.

[0031] The increased size directly led to a series of challenges during installation. In the transportation process, the oversized (some transformers are over 4 meters wide), oversized (over 5 meters high), and oversized (each unit weighs over 300 tons) characteristics made traditional road transport difficult to meet the requirements. Therefore, special transport vehicles (such as modular axle trucks) were needed, and the transport routes had to be surveyed and modified in advance, including removing billboards and utility poles along the way and reinforcing bridges. The transportation cost of a single unit could reach several million yuan.

[0032] The on-site installation phase presents equally significant challenges. Positioning the transformer requires large hoisting equipment (such as truck cranes or crawler cranes with a capacity of 500 tons or more), and the limited space within the substation often makes hoisting operations difficult. In addition, the exposure of the transformer body, the filling of insulating oil, and the vacuum treatment of high-voltage transformers have extremely high environmental requirements (such as humidity needing to be below 60%), requiring the construction of temporary dustproof sheds and the provision of dehumidification equipment. During the wiring and commissioning phase, due to the large current carrying capacity and high insulation requirements of the leads of large-capacity transformers, the connection between the leads and external equipment must be strictly controlled in terms of contact resistance and insulation distance. Any mistake in details may lead to equipment damage or operational failure.

[0033] In transformer design, the wiring method is one of the core factors that determine its electrical performance, and delta connection (represented by the letter "D") is a commonly used wiring method that is widely used in power systems.

[0034] The essence of delta connection is to connect the three windings of a transformer end to end to form a closed delta circuit. Specifically, the end of phase A winding is connected to the beginning of phase B winding, the end of phase B winding is connected to the beginning of phase C winding, and the end of phase C winding is connected to the beginning of phase A winding. The three connection points are used as outgoing terminals. The significant feature of this connection method is that the line voltage is equal to the phase voltage, i.e., U_line = U_phase, while the line current is √3 times the phase current (I_line = √3I_phase).

[0035] Compared with star (Y) connection, delta connection has unique technical advantages. First, delta connection can effectively suppress third harmonics. In a three-phase AC system, the third harmonic is a zero-sequence component with the same phase. It will form a circulating current in the delta winding, which consumes harmonic energy and thus prevents harmonics from affecting other equipment through the line. This characteristic makes it widely used in distribution transformers and can effectively improve power supply quality.

[0036] Secondly, delta connection provides a path for zero-sequence current. When a single-phase ground fault occurs in the system, the zero-sequence current can form a loop in the delta winding, which facilitates the relay protection device to quickly detect the fault and take action, thereby improving the safety of the system. Therefore, delta connection is often used on the high-voltage side of transformers in high-voltage transmission systems to enhance fault handling capabilities.

[0037] Third, the delta-connected windings withstand higher voltage (equal to the line voltage) but have relatively lower current. This allows for a reduction in the cross-sectional area of ​​the winding conductors, which reduces material costs to some extent. However, this also places higher demands on the insulation performance of the windings, especially in high-voltage transformers, where higher-quality insulation materials (such as Nomex paper, epoxy resin, etc.) are required.

[0038] The D-connector, or lead connection structure when the transformer coil is connected in a delta configuration, is a key component that connects the three windings in a delta manner. Its design and manufacturing process directly affect the operational reliability of the transformer.

[0039] Structurally, the D-connector mainly consists of a connecting conductor, insulation support, and fixing device. The connecting conductor is usually made of high-purity electrolytic copper (or aluminum, used for small and medium-sized transformers), and the form includes copper busbar, copper tube, or multi-strand soft copper wire. For large-capacity transformers, in order to reduce the influence of skin effect and proximity effect, the connecting conductor is mostly made of flat copper busbar or hollow copper tube. The hollow copper tube can also be cooled by oil to further increase the current carrying capacity.

[0040] The connection process of the leads is the core link. In small and medium-sized transformers, bolt connection or crimping is often used, that is, the winding output end and the lead conductor are fastened with bolts or hydraulically crimped to form a mechanical and electrical connection. In high-voltage and large-capacity transformers, in order to ensure the reliability and sealing of the connection, welding process (such as argon arc welding) is often used. The welded joint needs to be ground to ensure a smooth surface to reduce electric field concentration.

[0041] Insulation is another key aspect of D-connector lead design. Since the lead is in a high-voltage environment (especially near the winding output), it needs to be isolated from grounding components (such as the oil tank and iron core) by insulating materials. Insulation methods include wrapping insulation (wrapping with insulating paper or tape), bushing insulation (passing the lead through an insulating bushing), or casting insulation (casting and curing the lead entirely with epoxy resin). For transformers of 110kV and above, the insulation distance between the lead and the grounding component needs to be several tens of centimeters, and an equalizing ring needs to be installed in the insulation structure to improve the electric field distribution and avoid excessive local field strength that could lead to breakdown.

[0042] In the internal layout of the transformer, the D-connector lead wires need to avoid components such as the iron core and windings to ensure sufficient safety distance and reduce the impact on the internal magnetic field of the transformer. The lead wires should be as short and straight as possible to reduce line loss and impedance. If necessary, the layout can be optimized by adjusting the lead wire path or adding support points. In addition, the lead wires also need to have a certain mechanical strength to withstand vibrations during transportation and operation (such as electrodynamic forces during short circuits). Fiberglass binding tape or metal brackets are usually used for fixing.

[0043] In practical applications, the design of D-connectors needs to be optimized in conjunction with the transformer's capacity, voltage level, and usage scenario. For example, in 35kV distribution transformers, D-connectors are mostly connected with copper busbars, and the insulation treatment is mainly wrapping insulation, resulting in a relatively simple structure. However, in 1000kV UHV transformers, D-connectors need to use hollow copper tubes, combined with composite insulating bushings and equalizing rings. The entire structure needs to be optimized using electric field simulation software (such as Ansys and Maxwell) to ensure uniform electric field distribution.

[0044] The development of my country's power industry has driven transformer technology to continuously break through to higher voltage and larger capacity. The installation challenges brought about by the increased size and the optimization of wiring methods have always been the focus of industry research. The D-connection lead wire, as a structural realization of delta connection, not only ensures the reliable operation of transformers through the improvement of its technical details, but also reflects the concept of "giving equal importance to performance and reliability" in power equipment design. In the future, with the further maturation of ultra-high voltage technology and the application of new insulation materials and intelligent installation technology, the size control, installation efficiency and wiring reliability of high voltage and large capacity transformers will be further improved, providing a more solid support for the safe and stable operation of my country's power system.

[0045] Refer to the instruction manual appendix Figures 1 to 5 An improved coil lead structure includes a lower yoke 1, three vertical yokes 11 fixedly connected to the top of the lower yoke 1, an upper yoke 12 fixedly connected to the top of the vertical yokes 11, high and low voltage coils 13 arranged on the outside of the vertical yokes 11, inner leads 14 fixedly connected inside the high and low voltage coils 13, outer leads 15 fixedly connected inside the high and low voltage coils 13, and D-connected copper busbars 16 fixedly connected to the rear side of the three inner leads 14. Support mechanisms are provided on the lower yoke 1 and the upper yoke 12 for mounting and supporting various components. An insulation mechanism is provided on the upper yoke 12 to prevent the transmission of electrical energy.

[0046] It should be noted that the position of copper busbar 16 (D) should be adjusted downwards so that it is in the middle of the lead wire and the insulating terminal is above the lead wire.

[0047] Refer to the instruction manual appendix Figures 3 to 5 The support mechanism includes an auxiliary support component and a fixing component. The auxiliary support component is used to support the bottom of the high and low voltage coils 13, and the fixing component is used to install and support the insulation mechanism.

[0048] It should be noted that the auxiliary support components not only support the bottom of the high and low voltage coils 13, but also support the entire frame composed of the yoke columns.

[0049] Refer to the instruction manual appendix Figure 3The auxiliary support assembly includes a lower clamp 211 fixedly connected to the front and rear sides of the lower yoke 1, and two bases 212 fixedly connected to the bottom of the lower clamp 211.

[0050] It should be noted that the base 212 supports the two lower clamps 211, and the two lower clamps 211 support the entire transformer.

[0051] Refer to the instruction manual appendix Figure 5 The fixing assembly includes a low-pressure upper clamp 221 fixedly connected to the front side of the upper yoke 12 and a high-pressure upper clamp 222 fixedly connected to the rear side of the upper yoke 12.

[0052] It should be noted that the low-pressure upper clamp 221 and the high-pressure upper clamp 222 are symmetrically arranged, and the low-pressure upper clamp 221 and the high-pressure upper clamp 222 have the same size and shape.

[0053] Refer to the instruction manual appendix Figure 5 The insulation mechanism includes low-voltage insulation components and high-voltage insulation components. The low-voltage insulation components are used to prevent the transmission of low-voltage electrical energy, and the high-voltage insulation components are used to prevent the transmission of high-voltage electrical energy.

[0054] It should be noted that the number of insulators in low-voltage insulation components and high-voltage insulation components is different, and the number of insulators can be increased according to actual usage requirements.

[0055] Refer to the instruction manual appendix Figure 5 The low-voltage insulation assembly includes two first L-shaped fixing plates 311 fixedly connected to the top of the low-voltage upper clamp 221, and a low-voltage insulator 312 fixedly connected to the front side of the first L-shaped fixing plates 311.

[0056] It should be noted that the transmission of low-voltage electrical energy is prevented by low-voltage insulators 312, and the number of low-voltage insulators 312 is usually less than that of high-voltage insulators 322.

[0057] Refer to the instruction manual appendix Figure 5 The high-voltage insulation assembly includes three second L-shaped fixing plates 321 fixedly connected to the top of the high-voltage clamp 222, and a high-voltage insulator 322 fixedly connected to the rear side of the second L-shaped fixing plates 321.

[0058] It should be noted that the transmission of high-voltage electrical energy is prevented by high-voltage insulator 322, and the number of high-voltage insulator 322 is usually greater than that of high-voltage insulator 322.

[0059] Working Principle: The original connection method was optimized and adjusted. Specifically, the electrical connection position of the D-connector copper busbar 16 on the lead wire was significantly changed. The conventional connection point, located downwards in the upper region of the lead wire, was redesigned and adjusted to a more central position, precisely positioned in the middle of the lead wire height for reliable connection. Simultaneously, the installation position of the low-voltage insulator 312 remained properly arranged and fixed directly above the lead wire, ensuring effective insulation protection. Based on this optimized layout, the specific wiring method of the lead wire was further meticulously planned. It was explicitly required that the placement of the D-connector lead wire system or Y-connector sealing system be moved from the possible beginning and end areas, and instead carefully arranged and securely placed on the middle segment of the beginning and end lead wire structure itself. This crucial positional adjustment directly resulted in an important mechanical effect: significantly reducing the stress on the beginning and end leads. The overall height in the vertical direction effectively compresses the lifting range, reducing the height difference of the lead suspension points. When adopting the connection strategy of center exit, since the source of the lead, i.e. the exit point, is located in the middle, the vertical copper busbar section required to extend vertically upward or downward from the center exit point to the target connection point must also have its longitudinal physical distance shortened accordingly. The length of this vertical copper conductor is effectively controlled. This reduction in length is direct and clear. It is based on the above series of interrelated and synergistic process improvement measures, including moving the D-connection copper busbar 16 connection point down to the middle of the lead, keeping the low-voltage insulator 312 above the lead, and positioning the D-connection lead or Y-connection sealing wire arrangement point in the middle of the first and last lead to reduce its height, and the center exit causing the vertical path to be shortened, that the total amount of copper busbar material used in a specific circuit or device is effectively reduced.

[0060] The above embodiments only illustrate several implementation methods of this utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model.

Claims

1. An improved coil lead structure, characterized in that: The device includes a lower yoke (1), three vertical yokes (11) are fixedly connected to the top of the lower yoke (1), an upper yoke (12) is fixedly connected to the top of the vertical yoke (11), high and low voltage coils (13) are provided on the outside of the vertical yoke (11), inner leads (14) are fixedly connected inside the high and low voltage coils (13), outer leads (15) are fixedly connected inside the high and low voltage coils (13), and D-connected copper busbars (16) are fixedly connected to the rear side of the three inner leads (14). Support mechanisms are provided on the lower yoke (1) and the upper yoke (12), and the support mechanisms are used to install and support various components. An insulation mechanism is provided on the upper yoke (12), and the insulation mechanism is used to prevent the transmission of electrical energy.

2. The improved coil lead structure according to claim 1, characterized in that: The support mechanism includes an auxiliary support component and a fixing component. The auxiliary support component is used to support the bottom of the high and low voltage coils (13), and the fixing component is used to support the installation of the insulation mechanism.

3. The improved coil lead structure according to claim 2, characterized in that: The auxiliary support assembly includes a lower clamp (211) fixedly connected to the front and rear sides of the lower yoke (1) and two bases (212) fixedly connected to the bottom of the lower clamp (211).

4. An improved coil lead structure according to claim 3, characterized in that: The fixing assembly includes a low-pressure upper clamp (221) fixedly connected to the front side of the upper yoke (12) and a high-pressure upper clamp (222) fixedly connected to the rear side of the upper yoke (12).

5. An improved coil lead structure according to claim 4, characterized in that: The insulation mechanism includes low-voltage insulation components and high-voltage insulation components. The low-voltage insulation components are used to prevent the transmission of low-voltage electrical energy, and the high-voltage insulation components are used to prevent the transmission of high-voltage electrical energy.

6. An improved coil lead structure according to claim 5, characterized in that: The low-voltage insulation assembly includes two first L-shaped fixing plates (311) fixedly connected to the top of the low-voltage upper clamp (221) and a low-voltage insulator (312) fixedly connected to the front side of the first L-shaped fixing plates (311).

7. An improved coil lead structure according to claim 6, characterized in that: The high-voltage insulation assembly includes three second L-shaped fixing plates (321) fixedly connected to the top of the high-voltage clamp (222) and a high-voltage insulator (322) fixedly connected to the rear side of the second L-shaped fixing plates (321).

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