Development Trend of Dry Type Transformer

1. Multi-field development: From three phase pad mounted transformer to distribution transformers, power transformers, excitation transformers, subway traction rectifier transformers, high-current electric furnace transformers, nuclear power stations, marine and oil platforms and other special transformers and multi-purpose areas.
2. Multifunctional combination: from a single transformer to a fan-cooled, protective shell, the temperature of the computer interface, zero sequence transformer, power metering, blocking bus and side outlet and other multi-functional modular transformer development.
Dry-type transformer has a good development prospects, is expected to its development trend mainly in the following areas:
3. Energy-saving low noise: With the introduction of new materials, new techniques and new technologies such as new low-consumption silicon steel sheet, foil winding structure, core joint, environmental protection requirement, noise research, computer optimization design, Will make the future of Amorphous Core Transformers more energy efficient, more quiet.
4. High reliability: improve product quality and reliability, will be the tireless pursuit of people.
5. Large capacity: from 50 ~ 2500kVA distribution transformer-based dry-type transformers, to 10000 ~ 20000kVA / 35kV power transformers to expand, with the city increasing electricity load, urban network area more and more in-depth urban substation central area , Residential area, large factories, mines and other load center, 35kV large-capacity residential central power supply transformer will be widely used.
6. Environmental characteristics Certification: Based on the European standard HD464, carry out dry-type transformer resistance to weather (C0, C1, C2), resistance to the environment (E0, E1, E2) and fire (F0, F1, F2) Certification.

Technical characteristics of dry - type transformers

1. Anti-short-circuit ability, low-voltage winding copper foil is the height of the high-reactance, low-voltage current according to the winding between the ampere-turn balance requirements match, high and low voltage winding short circuit caused by the axial force is almost zero.
2. Overload capacity, if the same capacity of the transformer load loss is equal, then the corresponding copper cross-sectional area will be larger, the volume increases, the amount of filler resin, so the thermal capacity of the winding large, farady transformer short- Overload capacity.
3. Good anti-cracking performance, dry-type transformers using filler-type resin and copper foil structure, insulation and copper conductor thermal expansion coefficient of the most similar to effectively prevent the coil cracking. In the arc under high temperature combustion, does not produce any toxic gases.
4. Low noise, the transformer to take some special structure and design, making the noise greatly reduced, the overall noise level than the national professional standard noise value of 10-13dB (A) or more.
5. Lightning impulse withstand ability, lightning impulse voltage along the winding of the initial distribution of dry-type transformer winding insulation damage.
6. Flame-retardant characteristics, the use of filler-type resin casting process is conducive to environmental protection, Amorphous Metal Distribution Transformer with maintenance-free, moisture protection, anti-heat, flame retardant and self-extinguishing characteristics.

Dry-type transformers have the advantage of low noise

Dry-type transformers need to have a low noise level, need to be compact and have a lower weight to minimize the use of space, can be used exclusively for production activities. In many countries, users and specifiers have switched to encapsulated and open-type dry-type transformers as their desired solution. In Europe, some manufacturers have offered cast resin technology using Class B or Class F insulation systems. Many of the regions in Asia, including China and South Korea, have adopted this technology from Europe. However, these 11kv dry type transformer in the use of a decade later, its inherent limitations are becoming more users are more concerned about the problem. Increasing overload, environmental protection material requirements and long-term reliability have become disadvantages of these lower temperature solutions. Strict requirements can lead to cracking of large pieces of resin and accelerate the aging of materials, which will be less than 10 years time premature failure.

Differential Protection of Dry - Type Transformer

For the prefabricated compact transformer device, the dry-type transformer differential protection is the main transformer protection is installed according to the principle of circulating current. Transformer differential protection is mainly used to protect two-winding or three-winding transformer windings within and lead to the phase of the occurrence of a variety of short-circuit fault, but also can be used to protect the transformer single-phase inter-turn short circuit fault.
25kva pole mounted transformer are installed on both sides of the winding transformer, the secondary side of which is connected according to the circulating current method, that is, if the same level side of both sides of the current transformer is toward the bus side, the same level terminal is connected, Between the two lines connected in parallel current relay. The current flowing through the relay coil is the secondary current difference of the current transformer on both sides, which means that the differential relay is connected to the differential circuit.

Transformer no-load operation

200kva electrical transformer no-load operation refers to the transformer primary winding access to power, the secondary winding open working conditions. In this case, the current in the primary winding is called the no-load current of the transformer. The no-load current generates a no-load magnetic field. In the main magnetic field (that is, cross-linked one or two windings of the magnetic field) under the action, the first and second winding will be induced in the electromotive force.

When the 50 kva pole mount transformer no-load operation, although the secondary side no power output, but the primary side is still part of the power from the grid to absorb the active power to compensate for the magnetic saturation, in the core caused by hysteresis loss and eddy current loss referred to iron consumption. The hysteresis loss depends on the frequency of the power supply and the area of ​​the hysteresis loop of the core material. The eddy current loss is proportional to the square of the maximum flux density and frequency. In addition there is no load current caused by copper consumption. For different capacity of the transformer, no-load current and no-load loss size is different.

The automatic voltage booster is used to regulate the voltage

Power Engineers is known for reliability and continuous improvement in the field of rolling contact type automatic voltage controller, servo voltage controller, automatic voltage stabilizer, chemical process rectifiers, electroplating power rectifiers and special purpose transformers. The systems are designed and supervised by a team of qualified engineers having more than 35 years of experience to achieve best possible quality and total customer's satisfaction.
The automatic voltage booster

is used to regulate the voltage. It takes the fluctuate voltage and changes them into a constant voltage. The fluctuation in the voltage mainly occurs due to the variation in load on the supply system. The variation in voltage damages the equipment of the power system.

Special designs power transformers

When the transmitted power exceeds around 10 MVA, special designs are required to cope with the mechanical forces of short circuit currents, higher insulation levels and increased cooling requirements. For these ratings, liquid-filled farady transformers

 are usually used. The insulation between the windings becomes more and more demanding at Farady high voltage auto load booster Furthermore, resonance effects inside the winding itself have to be considered to avoid insulation failures during highly dynamic impulse stresses such as lightning strikes which may reach amplitudes of one to two thousands kilovolt with a 1 μs rise time.