6-10kV Three-phase oil-immersed two-windings power transformers ТМГ type

6-10kV Three-phase oil-immersed two-windings power transformers ТМГ type

Power range of transformers is 25 - 2500 kVA. They are submitted in a sealed version and completely filled by oil. Temperature volumetric changes of oil are offset by the tanks corrugated walls volume change, due to their elastic deformation. The advantage of sealed transformers are:
- smaller size due to the absence of an expansion tank;
- absence of direct contact between oil and atmosphere, which prevents a moisture absorption from an environment and as a result - there is no need for periodic maintenance.

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  Capacity, kVA Length, mm Width, mm Height, mm Oil weight, kg Total weight, kg
25  795  455  890  70 246 
  40  840 485  940  85 329 
  63  920  545  970 110 430 
  100 985 635 1035 131  568 
  160 1045 740 1120 214  778 
  250 1250 740 1230 274 1040 
  400 1370 800 1270 302 1326
  630 1480 910 1400 350 1735
  1000 1750  1095 1460 622 2700
  1600 2215  1235 2090 1174 5050
2500 2510 1600 1970 1575 6135

The transformers are comply to IEC-76, GOST 11677-85, GOST R 52719-2007,

TU U 31.1-13608660-062:2007.

The manufacture is certified by ISO 9001:2008.

Power oil-immersed down-step two-windings general-purpose transformers with rated power range from 10 to 2500 kVA and rated HV 6-10 kV are designed for indoor and outdoor installation.

Technical specification
Power transformers ТМГ-25-2500 are produced with primary windings rated power (high voltage) 6-10 kV and secondary winding (low vltage) – 0,4 kV. Connection scheme and group Y/Yn-0; ∆/Yn–11.

The voltage adjustment is provided without excitation. For this purpose, the transformers are equipped by high-voltage switches, which is connected to HV winding and allows voltage adjustment by steps ±2 х 2,5 % while the transformer disconnected of both HV and LV sides.

According to GOST 11677, the maximum deviation of transformers technical parameters are:
- short-circuit voltage ± 10%;
- short-circuit loses on the main branch + 10%;
- load losses + 15 %;
- total weight + 10 %.
The symbol structure:
ТМГ - XXX / 6(10) У(ХЛ)1
Т - Three-phase transformer
М - oil-iMMersed transformer with natural oil & air circulation 
Г – hermetic (sealed)
XXX - a rated power, kVA
6(10) – voltage class (grade) of high voltage winding (HV), kV

У(ХЛ)1 – climatic composition and accommodation category as per GOST 15150-69;

Terms of use:
Altitude – up to 1000 m.
Ambient temperature:
- for a temperate climate - from –45ОС to +40ОС («У» composition);
- for a cold climate - from –60ОС до +40ОС («ХЛ» composition).
Relative humidity– less than 80% at +25ОС.

The transformers are not suitable for operation:
- In the explosive and corrosive medium (containing gases, vapors, dusts and others in an increased concentration);
- Vibration or shock;
- With frequent on-load reconnections on the feeding side - more than 10 times per 24 hours.
The Transformers Design:
ТМГ - type 25-2500 kVA transformers has rectangular shape, they are made using corrugated walls without oil extender. For lifting (movement) a tank and an entire transformer, the hooks arranged at the upper frame of the tank are used. There where a valve (tube) on the tanks cover, and another tube for pouring oil is placed at the bottom of the tank. Also the bottom has drain plug oil valve (tube) for sampling, and grounding bolt.
An active part consists of a magnetic core, made of cold rolled electrical steel, windings and the high-voltage switch. 
The windings are aluminium (copper - as per customers request).
HV and LV bushings are outdoor installation, removable, located on the lid, an insulators are polymeric. For oil level check, float oil indicator also installed on the tank's lid. For measure of oil's upper layer's temperature, a thermometer mounted on tralsformer's lid. Temperature volumetric oil fluctuations are offset by elastic deformation of the tank corrugated walls. 
In the ТМГ type transformers, transformer oil inside a tank has no contact to external air and not oxidized, so the transformers does not require any extra expenses at comissioning and there's no need of preventive maintenance and technical audits. During an entire lifetime, there is no necessary in oil analysis and re-generation.
Rollers are used for longitudinal and lateral movement of transformers of 1000 kVA and more rated power.