6-10kV Oil-immersed three-phase two-winding power transformers TM type

  Technical characteristics
 Power transfrmers TM type are produced with primary winding`s rated voltage (high voltage) up to 10kV and with secondary winding`s rated voltage (low voltage) 0.4 kV, rated power range 25-2500 kVA. As per customers request, it`s possible to made transformer with up to 4000 kVA rated power.
At customer's request, other HV and LV combinations are possible.
Connection scheme and group Y/Yn-0; ∆/Yn–11.
  Voltage adjustment method - without excitation (PBV). For this, the transformers are equipped by high-voltage selectors, connected to high voltage winding and allows high voltage adjustment while HV and LV sides of the transforner are disconnected of a grid, by steps ±2 х 2,5 %.
  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:
TM - XXX / 6(10) Y(HL)1
T - Three-phase transformer
M - oil-iMMersed transformer with natural oil & air circulation 
XXX - a rated power, kVA
6(10) – voltage class (grade) of high voltage winding (HV), kV

Y(HL)1 – climatic composition and accommodation category as per ГОСТ 15150-69;

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

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:
TM type transformers has a welded rectangular-shape tank. 25-2500 kVA transformers made using corrugated walls as cooling surface. Transformers with rated power 4000, 6300 kVA and more made using pipe radiators. Under customer`s request, manufacture of TM-type transformers 25-2500 kVA using pipe radiators is also possible. For lifting (movement) a tank and an entire transformer, the hooks arranged at the upper frame of the tank are used. There were an oil-pouring valve (tube) on the tank`s lid , and another tube for oil drain is placed at the bottom of the tank. Also the bottom has oil valve (tube) for sampling, and grounding bolt.
   An active part consists of a magnetic core, made of cold rolled electrical steel, windings and high-voltage selector. 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 25-1600 kVA) or porcelain (for 2500 – 6300 kVA).
   When the input current is 1000 A or above, the top of the current-carrying rod attached by special terminal clamp with a shovel, which provides connection of a flat busbar.
Oil expander provides presence of oil in a tank in all transformer`s operation modes and in any ambient temperatures. For oil protection against of ambient air influence, there is an air-dryer filled by sorbent absorbing humidity out of incoming air.
  Level indicators for oil level monitoring, attached to the oil expander`s side end, has three reference marks corresponding to the oil level in stopped (disconnected) transformer at different temperatures:
–45^ОC, +15^ОC, +40^ОC (Y performance)
–60^ОC, +15^ОC, +40^ОC – (YHL performance).
  For measure of oil's upper layer's temperature, a thermometer mounted on transformer's lid. The thermal indicators are installed on transformers of 1600 kVA and more rated power.
  Rollers are used for longitudinal and lateral movement of transformers of 1000 kVA and more rated power.