Dry - type transformer low - voltage outlet mode

1, low-voltage standard closed bus: If the use of closed wiring project bus (also known as plug-in bus or bus-intensive busway), the corresponding high voltage auto load booster provide standard closed bus terminal to facilitate connection with the external busbar.
Enclosure (IP20) products, enclosed on the top cover of the housing provide closed bus flanges; no enclosure (IP00) products, only closed busbar terminals.
2, low-voltage side of the standard side line: when the dry-type transformers and low-voltage distribution panel placed side by side, in order to facilitate the connection between the terminals, transformers can provide low-voltage side of the line, usually with GGD, GCK, MNS and other low- Transformer factory and switchgear factory to sign the interface with the minutes to confirm the detailed size with the interface to ensure the smooth installation of the scene.
3, low-voltage side of the line stand side stand: and the horizontal side of the outlet similar to the elected domino screen and other busbar layout for the vertical 100kva single phase pole mounted transformer of low-voltage distribution screen, the transformer can provide low-voltage stand side-qualifying outlet.
Transformer components include the body (core, winding, insulation, lead), transformer oil, fuel tank and cooling devices, pressure regulator, protection devices (moisture, airway, gas relays, oil conservator and temperature measurement devices ) And outlet bushing.

Protection of dry - type transformers

Usually IP20 protective shell, to prevent the solid foreign body greater than 12mm in diameter and rats, snakes, cats, birds and other small animals to enter, resulting in a short-circuit power failure and other malignant failure, to provide security for the live part of the barrier. If you need to install the 100kva distribution transformer in the outdoors, you can choose IP23 protective shell, in addition to the IP20 protection, but also to prevent the vertical line into a 60 ° angle within the water droplets into. But the IP23 shell will reduce the cooling capacity of the single phase pole mounted transformers, the choice should pay attention to the reduction of its operating capacity

Dry - type transformer wiring

1, pole mounted distribution transformer "input" and "output" terminal with a megger test with the ground insulation resistance. 1000V megger measurement, the resistance is greater than 2M ohms.
2, the transformer input and output power line cross-section wiring should meet the requirements of the current value of the size; in accordance with the 2-2.5A / min2 current density configuration is appropriate.
3, the input and output of three-phase power line should be the transformer wiring board bus color yellow, green, red, respectively, then A phase, B phase, C phase, neutral line should be neutral with the transformer neutral line, grounding line, single phase step down transformer Shell and the transformer center point connected to the usual we said that the ground and the neutral line are derived from the transformer neutral point. (Such as a transformer box should be connected with the corresponding ground box logo).
Check the input and output lines to make sure they are correct.
4, the first no-load power, observe the test input and output voltage to meet the requirements. While observing the machine
Internal abnormal sound, ignition, odor and other abnormal phenomena, if abnormal, please immediately disconnect the input power.
5, when the load test is completed and normal, before access

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.