What are the faults that dry type transformers are prone to? I bought a new dry type transformer and

The common faults of the core part of the transformer are mainly the insulation damage between the core pieces, which causes the oil temperature to rise and the oil color to darken; The grounding piece is broken or the core is in poor contact, causing a discharge sound between the core and the fuel tank; Abnormal vibration or noise occurs after the core is loosened.

The common faults of the transformer winding part mainly include interphase or interturn short circuit, high-voltage fuse breakage, external spray after oil temperature increases, three-phase resistance unbalance, primary side current increase and secondary side voltage instability; After the coil is broken, there is a discharge sound, and there is no current and voltage in the broken phase; After the winding breaks down to the ground, there is an inter-turn short circuit and the high-voltage fuse breaks. The common faults of tap changers are melting and burning on the surface of the contact, which causes the oil temperature to rise, the discharge sound on the contact surface or the high-voltage fuse to break. The interphase contact discharge or the discharge of each tap will make the oil pillow cover smoke, the high-voltage fuse will break, and there will be a gurgling sound. You search for Minrong Electric Group, there are a lot of transformers on the ground, practical, about the analysis and treatment of transformer faults These types of information are also very complete, Minrong transformers are also very good, it is recommended to learn about Minrong Electric Group.

The main faults of the casing part are ground breakdown and casing discharge, which causes the high-voltage fuse to break, which should be cleaned regularly.

The dry-type transformer is mainly composed of an iron core composed of silicon steel sheet and an epoxy resin cast coil, an insulating cylinder is placed between the high and low voltage coils to increase electrical insulation, and the coil is supported and constrained by a cushion block, and the fasteners of its parts overlap have anti-loosening properties.

Its advantages can be broadly divided into the following points:

Safe, fireproof, pollution-free, can run directly in the load center;

Adopting domestic advanced technology, high mechanical strength, strong anti-short circuit ability, small partial discharge, good thermal stability, high reliability and long service life;

Low loss, low noise, obvious energy-saving effect, maintenance-free;

Good heat dissipation performance, strong overload capacity, and increased capacity operation when forced air cooling;

Good moisture-proof performance, suitable for operation in high humidity and other harsh environments;

Dry-type transformers can be equipped with a complete temperature detection and protection system. The intelligent signal temperature control system can automatically detect and display the respective working temperature of the three-phase winding, automatically start and stop the fan, and have alarm, trip and other function settings;

Small size, light weight, less floor space, low installation cost.

Weifang Hengxin Electric has been producing dry-type transformers for nearly 20 years and has rich experience in production and research and development. Welcome customers to communicate.

Advantages of dry-type transformers.

1. Good fire performance, no flammable resin, no toxic gas, flame retardant and self-extinguishing characteristics.

2. Low loss and low noise.

3. No pollution, maintenance-free.

4. Good insulation performance, no partial discharge, strong resistance to lightning impact.

5. Good mechanical strength, strong resistance to temperature changes and short circuit.

6. Moisture resistant, can operate under high humidity.

7. The installation is economical, it can be installed with the load center, and no special foundation is required.

8. Small size and light weight.

9. Automatic temperature monitoring and protection.

Disadvantages of dry-type transformers.

1. The cost is high, the ability to resist harsh environments is relatively poor, and it can only be installed indoors under normal circumstances.

2. If the dry-type transformer coil is broken, it will be scrapped directly.

3. The dry-type transformer is durable, and the probability of winding failure is small. But once it fails, the whole setting changes, i.e. the limb is used to complete the change of the high voltage and low voltage windings.

Dry-type transformer: relies on air convection for cooling, generally used for local lighting, electronic circuits. Transformers such as machinery and equipment, in the power system, general steam turbine transformers, boiler transformers, ash removal transformers, dust removal transformers, desulfurization transformers, etc. are dry-type transformers, with a conversion ratio of 6000V 400V and 10KV 400V, which are used for loads with rated voltage of 380V.

The analysis report on market demand and investment strategic planning of dry-type transformer industry shows that China has become the largest country in the world in terms of dry-type transformer production and sales. Before the foreign high and low voltage electrical products, occupy some important domestic markets, but the dry-type transformer from the end of the 20th century, almost no import from abroad, in the domestic key projects and major projects, it is difficult to find a trace of foreign dry change.

At present, the pace of urban and rural power grid construction is accelerating, and China's power generation and electricity consumption are increasing day by day. Generally speaking, for every 1kW of additional power generation, 11kW of total transformer capacity needs to be added; Among them, the Satons distribution transformer accounts for about 1 3-1 2 of the total capacity of all transformers. It is estimated that dry-type distribution transformers account for about 1 5-1 4 of all distribution transformers.

Driven by the investment in power grid construction, the transformer industry is booming, and the output will maintain a growth rate of about 20% after 2010. According to the historical experience and the change of transformer voltage level structure, the proportion of distribution transformers is about 40%, and according to the proportion of 40%, China's new dry-type transformer output will reach about 200 million kva this year.

In the past 20 years, with the development of the world economy, dry transformer has achieved rapid development in the world, especially in the distribution transformer, the proportion of dry transformer is increasing, according to statistics, in developed countries such as Europe and the United States, it has accounted for 40 50% of the distribution transformer. In China, it accounts for about 50%. From the point of view of output, China since 1989 after the second urban network transformation meeting, the output of dry-type transformers has increased significantly, from the 90s of the 20th century, the annual rate of about 20% increase, the total output in 1999 has approached 10,000 MVA (the value has greatly exceeded 10 years ago, **4,005 MVA), and the total output in 2002 reached 20,000 MVA, in 2004 has reached 32,000 MVA.

Such a growth rate is also unprecedented in the world.

From the above data, it can be seen that China has become one of the countries with the largest dry variable production and sales in the world, and has been at the world's leading level in terms of factory scale, product capacity, voltage, etc.

The performance and function of the dry-type transformer are mainly reflected in the stability of the voltage can be adjusted, and the basic stability of the voltage can be guaranteed in the circuit, so that the circuit can be kept smooth, and lay a solid foundation for the safe operation of various electrical appliances. What are the components of dry-type transformers and their roles in circuits? Let's take a look with Tongyida :

The main structure of the dry-type transformer:

1.Core. The core is the main part of the magnetic circuit in a dry-type transformer.

Usually made of hot-rolled or cold-rolled silicon steel sheets with high silicon content, thickness, and coated with insulating paint on the surface, the iron core is divided into two parts: the core column and the transverse piece, and the core column is sleeved with windings; The transverse piece is used to close the magnetic circuit, and the basic form of the core structure has two types: heart type and shell type.

2.Winding. The winding is the circuit part of the dry-type transformer, which is wound with double wire (paper pack) insulated flat wire or enameled round wire.

The basic principle of dry-type transformer is the principle of electromagnetic induction, and now the single-phase double-winding dry-type transformer is used as an example to illustrate its basic working principle: when the voltage & is added to the primary side winding, the current flows, and the alternating magnetic flux is generated in the iron core, and these magnetic fluxes are called the main magnetic flux, under its action, the windings on both sides induce the electric potential 1,2 respectively, and the induced electric potential formula is: e=where:

e -- the effective value of the induced potential.

f -- frequency.

n -- number of turns.

Dry-type transformer characteristics and applications:

Features of dry-type transformers:

1.Safe, fireproof, pollution-free, can run directly in the load center;

2.Adopting domestic advanced technology, high mechanical strength, strong anti-short circuit ability, small partial discharge, good thermal stability, high reliability and long service life;

3.Low loss, low noise, obvious energy-saving effect, maintenance-free;

4.Good heat dissipation performance, strong overload capacity, and increased capacity operation when forced air cooling;

5.Good moisture-proof performance, suitable for operation in high humidity and other harsh environments;

6.Dry-type transformers can be equipped with a complete temperature detection and protection system. The intelligent signal temperature control system can automatically detect and display the respective working temperature of the three-phase winding, automatically start and stop the fan, and have alarm, trip and other function settings;

7.Small size, light weight, less floor space, low installation cost.

Dry-type transformers are widely used in local lighting, high-rise buildings, airports, docks, CNC machinery and equipment and other places. Cooling methods are divided into natural air cooling (AN) and forced air cooling (AF).

Summary. Pro, after a small degree of inquiry.

The cause of the dry-type transformer's non-electric fault alarm is a non-electric fault, which may be overheating protection.

What is the cause of the non-electric fault alarm of dry-type transformer?

Pro, the reason for the non-electric fault alarm of the dry-type transformer after a small inquiry is a non-electric failure, which may be overheating protection.

1. Check whether the oil level, winding temperature and sound of the dry-type transformer are normal, and whether it is caused by oil leakage of the dry-type transformer. 2. Check whether there is gas in the gas relay, if so, use the gas intake device to extract part of the gas, check the gas color, gas pants collapse smell, and flammability, so as to determine whether it is the internal fault of the dry-type transformer or the precipitation of dissolved air in the oil, and take oil samples and gas samples at the same time for gas chromatography test, so as to further judge the fault nature of the dry-type transformer according to the relevant regulations and guidelines. 3. If the gas in the gas relay is colorless, odorless and non-flammable, and the chromatographic analysis is judged to be air, the dry-type transformer can continue to operate; 4. The signal action is due to the fact that Hu Douyuan acts because the remaining air in the oil escapes or the strong oil circulation system inhales the air, and the signal action time interval is shortened one by one, which will cause tripping, the gas protection should be reconnected to the signal; 5. The gas is a flammable finger cover, and its content exceeds the normal value after chromatographic analysis, and a comprehensive judgment is given by the routine test, such as indicating that the dry-type transformer has a fault inside, and the dry-type transformer must be shut down in order to analyze the cause of action and carry out inspection and test.

The above are the main fault checks for dry-type transformer alarms.

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There is no dead rule that you must use dry change, depending on the needs of the user.

1.The dry transformer is generally DYN11 connection, which can withstand higher unbalanced current (the unbalanced current of the neutral line can reach 75% of the rated current), while the oil transformer is generally YYN0 connection, and the unbalanced current it bears is 25% of the rated current.

2.The dry change can be maintenance-free, mainly for dust removal. The oil change must be tested every other year whether the transformer oil is qualified, if it is unqualified, it must be replaced with new transformer oil, and the dehydrating breather should be replaced if it turns yellow.

3.Dry change is epoxy resin for insulation, fireproof. The insulating oil turned into oil will spontaneously ignite when it reaches the ignition point.

4.The overload capacity of the dry change is better than that of the oil change, because it is open, there is a fan to cool down, and the cooling performance is better than the oil change.

The main constraints of dry-type transformers need to be considered, including heat generation, maintenance and safety. Dry-type transformers are passed by these three important factors, especially the importance of their excellent performance.

An inherent by-product of the retrofit process is heat, specifically, "I2R" (i = current, r = resistance) heating, which occurs when the current through the wire is running. Thermal decomposition of the materials and insulating materials of the transformer composition, resulting in reduced efficiency and shorter service life. The heat of the transformer is best controlled by the oil used in the oil-filled transformer, which conducts heat from the heat-generated part while protecting the other internal transformer operating principles.

This is why these transformers are used in the highest voltage applications such as high-voltage transmission.

But with the right size and location, as well as fans at the right time, a dry-type transformer, which provides excellent, low-heat service by ventilating and cooling in cramped enclosures and indoor situations where an oil leak could cause a disaster or significantly harm the environment. Obviously, a system without these threats provides enhanced security for indoor applications. Dry-type transformers will typically contain a design with greater internal clearance for better heat dissipation.

Ventilation without fire, oil filtration, or toxic gases is required, while transformers can be placed close to the load, minimizing secondary line losses. But dry-type transformers also reduce maintenance, eliminating the need to change transformer oil, while avoiding contaminants and compositions that are needed, checking proper oil insulation and cooling.

The dry transformer is used in spaces with a high indoor fire rating, and the fire performance is also better than that of the oil transformer. However, due to the limitations of manufacturing, cooling and insulation, the current voltage level is only used for distribution transformers with a capacity of 35kV and below and a capacity of 2500kva and below.

1. Adjust the gear switch of this transformer

As shown in the figure, the middle part is the terminal of the transformer tap wiring, and the transformer is arranged up and down, and there are also left and right arrangements. Now the position is that the rated voltage gear is the gear, the rated voltage is 10000V, the gear voltage is the highest, usually 10500V, and the gear is the lowest voltage, usually 9500V. If you want to increase the output voltage, adjust it down (3 gears), if you want to lower the output voltage, adjust it up (1 gear), and all three should be adjusted down or up at the same time.

There are also five gears, 1 gear 11000V, 2 gear 10500V, 3 gear 10000V, 4 gear 9500V, 5 gear 9000V, the original gear is in 3 gears, to increase the output voltage to 4 or 5 gears, to reduce the output voltage to 2 or 1 gear, three to be adjusted down or up at the same time.

2. Adjust the gear switch of the upper transformer.

If the output voltage of the transformer is still low, and the 10kV line is often lower than 10000V, you can contact the power supply department to adjust the upper 35kV 10kV or 110kV 10kV transformer to increase the 10kV voltage by one level.