With the gradual adjustment of China's industrial structure, the state attaches more and more importance to energy-saving products. For transformers, that is, the requirements for loss and noise are higher and higher. The original S11 products can not meet the market demand. The S13 products with lower loss have gradually become the mainstream of the market. At present, most transformer manufacturers in China produce traditional laminated core transformers, but because of their own structure characteristics, it is difficult to make great breakthroughs in reducing loss and noise. Although it can barely meet the loss requirements of S13 products, its production cost is too high and the waste of raw materials is serious.

In this case, the closed three-dimensional coil core transformer with more reasonable structure, lower loss, noise and cost has been developed gradually. After several years of development, it has gradually been recognized. This transformer can easily meet the loss requirements of S13 products, and it is more material-saving. So the country is now mainly promoting this product. But the disadvantage of this kind of transformer is obvious, that is, its production efficiency is relatively low, and its requirements for production equipment are also very high. The original manufacturers of traditional laminated transformer need many new equipment to produce this kind of product, inadvertently adding a lot of pre-investment, which reduces the advantages of traditional transformer a lot.

In this context, it is imperative to develop a more energy-saving, material-saving, higher production efficiency and lower requirements for production equipment. Based on the above situation, after years of design and development, our company has developed the S13 open triangular three-dimensional coil core transformer, which solves the problems of loss and noise reduction of traditional laminated transformer, high cost, low production efficiency and difficult production of conventional closed three-dimensional coil core transformer. It is a new type of energy-saving power transformer, which can easily meet the loss standard of S13 transformer grade 1 energy efficiency, and fully respond to the overall requirements of energy-saving, green and environmental protection of products of the country.

Two Technical Principles

The three-dimensional coiled core transformer fuses the traditional stacked core transformer with the closed three-dimensional triangular coiled core transformer, and divides each single core frame of the closed three-dimensional triangular transformer into two separate parts. The core of each part is a 1-fold, 5-level joint, which not only improves the mechanical strength of the core, but also reduces the noise and no-load current of the core. It also improves the insertion efficiency when the iron yoke is inserted into the core. It can insert 5 pieces at a time. In production, the silicon steel sheet is cut through the longitudinal shear line and the curve feeder, then the four corners of the core are folded into octagonal shape by the newly developed core bender, the lower half of the core is overlapped on the lower clamp, then the wire package is set, and the upper half of the core is inserted with the lead sheet.

Core assembly diagram:

The products are suitable for all kinds of oil-immersed transformers, dry-type transformers and all kinds of large capacity special transformers.

Four Major Technological Innovations

Open three-dimensional coil core combines the main advantages of traditional stacked core and closed three-dimensional coil core.

Compared with traditional laminated core, 1. Open three-phase coil core transformer has fully symmetrical magnetic circuit, small no-load current, reduced third harmonic and greatly reduced noise; 2. The power-saving effect is remarkable, can easily meet the standard of S13 transformer, compact structure, small size, low cost, strong heat dissipation and overload capacity; 3. Silicon steel tape is processed into trapezoidal material strip, which is adopted. The nesting method is used to cut the material, and there is no waste when the material is opened, and no waste material is wasted.

Compared with the closed three-dimensional coil core, the product has the following advantages besides all the advantages of the closed three-dimensional coil core:

1. Because of its structural characteristics, its coil can be wound independently. Traditional winding machine can be used without introducing new winding equipment. Moreover, its winding process is much simpler than closed-end winding, which reduces the difficulty of winding.

2. Easy to repair, the original closed three-dimensional coil core must have a special winding machine and die to repair, repair is very difficult, basically need to return to the original factory repair, but because of its structural characteristics, our company's open three-dimensional coil core only needs to remove the yoke, pull out the coil to repair alone, repair simple, do not need to return to the original factory repair;

3. The difficulty of producing large-capacity transformers is low. Because the original closed-ended three-dimensional coil core has to winding coils on the core, when it needs to produce large-capacity transformers, its core die, core winding machine and winding machine need special design, and the requirements for equipment are very high. The actual production of transformers is also very difficult, so it can only be used as a prototype, which is not suitable for volume. The open three-dimensional coil core of our company can be widely used in large capacity transformers because its coils are wound independently and the production of the core does not require dies.

4. Because the silicon steel sheet is only subjected to part of shear stress and bending stress in the production process, the stress is small, so the annealing can be avoided, which greatly reduces the production process and cost.

Five Technical Indicators

1. Main technical performance indicators

Compared with the traditional laminated core transformer, because the traditional laminated core has many oblique joints at each layer edge connection, the magnetoresistance and iron loss will increase, the excitation current of the transformer will increase correspondingly, the power factor will be reduced, and the power supply quality of the power grid will be seriously affected. However, the open triangular three-dimensional coil core does not have the above problems. Because the core is composed of three identical double-open cores, each frame has good symmetry, balanced three-phase magnetic circuit, less third harmonic component, small no-load current, low core loss and low noise, the transformer with open three-dimensional coil core structure can easily achieve S13 zero-deviation product, and its structure is compact, and the utilization rate of core is low. Compared with the S13 core product, the cost can be greatly reduced.

From the table above, it can be seen that compared with the traditional stacked core transformer, the copper consumption of the open three-dimensional coil transformer with the capacity of 315KA of the S13 type produced by us has decreased by about 7%, the silicon steel consumption has decreased by about 14%, the oil consumption of the transformer has decreased by about 7%, and the steel plate consumption is almost the same. The overall cost of the open three-dimensional coil transformer has decreased compared with the traditional stacked core transformer. Compared with the closed three-dimensional coil core transformer, although the material cost is slightly increased (about 1%), the production process and efficiency are greatly improved.

2. Comparisons of similar technologies at home and abroad

The open three-dimensional triangular coil transformer produced by our company has made a lot of technical improvements on the basis of the original closed three-dimensional coil core. It has solved the problems of loss and noise reduction of traditional laminated transformer, high cost, low production efficiency and difficult production of closed three-dimensional coil transformer. Its structure is more reasonable, performance is better, and manufacturing cost is obviously reduced. It not only meets the requirements of energy saving in power industry, but also meets the cost and quality objectives of manufacturing enterprises. It is a new type of energy-saving power transformer. Compared with traditional laminated core transformer and closed three-dimensional coiled core transformer, it has the following advantages:

1) Air gap is less than the traditional stacked core, only 2, which greatly reduces the magnetoresistance of the core, reduces magnetic leakage, and reduces the no-load current to about 0.1-0.3, which can improve the power factor and improve the quality of power supply.

2) Low noise, better play to the magnetic conductivity of cold rolled silicon steel sheet with high magnetic conductivity. Flux basically flows in the direction of stacking core. Three-phase magnetic circuit and flux are completely symmetrical. The design of working magnetic density is more reasonable and the magnetoresistance is obviously small. Therefore, the product noise is greatly reduced and meets the requirements of environmental protection.

3) The magnetization direction of the coil core is basically the same as the rolling direction of the silicon steel sheet. The length of the three-phase magnetic circuit is completely equal and the sum of its lengths is the shortest. The magnetic circuit is completely symmetrical and the magnetic flux distribution is uniform in all parts of the magnetic circuit, which ensures the balance of the three-phase voltage, reduces the third harmonic component and improves the efficiency of the power supply system.

4) Low harmonics. All transformer connection groups adopt Dyn11. The high voltage triangular connection method provides a circulating circuit for the third harmonic, which will not diffuse to the higher power grid, reduces the harmonic current of the power grid, and improves the power supply efficiency of the power grid.

5) Strong overload capacity, due to its low loss and calorific value

4) The difficulty of producing large-capacity transformers is low. The production of large-capacity transformers with closed three-dimensional coil cores requires special design of core dies, core winding machines and winding machines. The overall size of the equipment is huge and the operation is difficult. The production of open three-dimensional coil cores in our company does not require dies and core winding machines, and can be widely extended to high-capacity and high-voltage transformers. Device.

5) No annealing is needed. Because of the enormous tension stress produced in the process of core winding, the closed-ended three-dimensional coil transformer must be annealed to remove the stress. Because our products are only subjected to very small shear force in the production process, no annealing is needed, which eliminates the damage to the environment in the annealing process and protects the environment.

6) The cost of adjusting the design scheme is low according to the market situation. Once the design of the closed three-dimensional coil core is determined, the size of the coil-winding gear disc is also determined. If the design of the coil is to be changed in the future, the gear disc should be re-manufactured. The design of the open three-dimensional coil core can not be adjusted at any time with the change of the price of raw materials. However, the open three-dimensional coil core has no such difficult problem, but highlights its strain. Sex and flexibility, to meet the needs of the market.

7) The advantages of producing dry-type transformer are obvious. Closed three-dimensional coiled core dry-type transformer needs to pour the whole body into pouring irrigation. It is very difficult to pour. It requires high technology, covers a large area and has a low utilization rate of pouring irrigation. The open three-dimensional coil core dry-type transformer only needs to pour coils separately and then insert them into the core, which greatly simplifies the pouring process, improves the utilization ratio of equipment and reduces the requirements for equipment.

Sixth, the role and significance of promoting scientific and technological progress in the industry

1. It can completely replace the traditional stacked core transformer. Because of its low technological difficulty and low equipment requirements, it is difficult to popularize.

2. The energy-saving effect is good, and the no-load loss of the original S11 product is reduced by 20%.

3. The manufacturing cost of the product is low. Compared with the laminated transformer, the product cost has been greatly reduced, and the corresponding procurement cost has also been greatly reduced.

4. Because of its balanced three-phase magnetic circuit, small no-load current and small third harmonic component, the power supply quality of power grid is greatly improved.

Seven Popularization and Application Prospects

In addition to technology, equipment, technology and tooling, the promotion of a new structure transformer also needs to meet the needs of the market. Open-ended coil core transformer has many bright spots. Its outstanding points are that it not only saves materials, but also improves the performance of transformers. It also increases the production efficiency of transformers, especially for transformers with high energy efficiency index, it has more advantages, such as oil. Change S13 and above, dry change SCB13 and above. According to the planning of relevant national departments, S11 is the minimum energy efficiency standard (three-level standard), the target energy efficiency standard is S13 (second-level energy efficiency), and the expected energy efficiency standard is S15 (first-level energy efficiency). Since 2012, the proportion of S11 transformers purchased by the State Grid has been decreasing year by year. Most of them are transformers purchased by S13. Looking forward to the transformer Market in the next three to five years, S11 energy-efficient transformers will gradually be eliminated from the market. The market will be dominated by S13 energy-efficient transformers, supplemented by S15 transformers. It can be seen that the three-dimensional coil core transformer meets the needs of the market. Because of its low production efficiency and high requirements for production equipment, it is difficult to popularize the closed-coil transformer. However, the open-coil transformer developed by us is superior to the closed-coil transformer in terms of production efficiency, process difficulty and production cost, so it is easy to popularize. 3) Maintenance is simple. Because of the closed structure of the core, the coil of the closed three-dimensional coil core can not be removed from the core. It must be repaired by a professional winding machine back to the original factory. Maintenance is very difficult. Because the upper yoke of the open three-dimensional coil core is separated, the coil can be easily removed and repaired after the upper yoke is removed, just like the conventional laminated core transformer. 。 To a large extent, it solves the problem that the closed three-dimensional coil core transformer can not be maintained, ensures the users'doubts after sales, and reduces unnecessary expenditure for users, which saves energy and protects the environment.

4) The difficulty of producing large-capacity transformers is low. The production of large-capacity transformers with closed three-dimensional coil cores requires special design of core dies, core winding machines and winding machines. The overall size of the equipment is huge and the operation is difficult. The production of open three-dimensional coil cores in our company does not require dies and core winding machines, and can be widely extended to high-capacity and high-voltage transformers. Device.

5) No annealing is needed. Because of the enormous tension stress produced in the process of core winding, the closed-ended three-dimensional coil transformer must be annealed to remove the stress. Because our products are only subjected to very small shear force in the production process, no annealing is needed, which eliminates the damage to the environment in the annealing process and protects the environment.

6) Adjusting the design scheme according to the market situation, the cost is low, and the closed three-dimensional coil core is low.