Power transformer:

Stationary power oil step-down three-phase transformers two-winding general purpose normal constructive performance from 10 to 6300 kVA voltage up to 35 kV inclusive, as well as transformers of special design (flange and sealed) type TMF, TMZ, TMG, TMGF are intended for
needs of the economy.

Transformers are suitable for internal and external installation and for operation in the following conditions:
– height above sea level up to 1000 m;
– ambient air temperature from minus 45 ºС to plus 40 ºС
for transformers intended for operation in temperate climates (execution “U” according to GOST 15150-69); from minus 60 °C to plus 40 °C
for transformers of the “HL” design (design for a cold climate);
– the relative humidity of the air is not more than 80% at 25 °C for transformers of the “У” and “УХЛ” versions.

Transformers are not designed to work in the following conditions:
– in an explosive and aggressive environment (containing gases, evaporation, dust of high concentration, etc.);
– with vibration and shaking;
– with frequent switching on from the power supply side.
Transformers of the TME and TMB types allow operation in the conditions
shaking and vibration associated with the natural operation of excavators and drilling rigs, as well as the influence of inertial forces during acceleration and braking of the rotary platform of the excavator with an acceleration of up to 0.5 m/s2, roll and trim up to 10 º.

Technical data:

Transformers are produced with nominal voltages
– primary winding (higher voltage winding) 6, 10, 20, 35 kV
including.
– secondary winding (low voltage) – 0.4; 6; 6.3; 10; 10.5 kV
– circuits and winding connection groups, respectively Yyn-0, Dyn-11, Yzn-11.
– transformers with capacity from 1000 to 6300 kVA with primary winding voltage (high voltage) of 35 kV and secondary winding voltage (low voltage) of 6.3 or 10.5 kV are manufactured with Yd11 or Yy0 circuit and group of connections.
– transformers with capacity from 1000 to 6300 kVA with primary winding (high voltage) voltage of 10.5 kV and secondary winding (low voltage) – 6.3 kV are manufactured with Yd11 or Ydn11 circuit and group of connections.

Structure and operation of the product and its components:

Transformers consist of the following main components:
– a tank with radiators (coolers);
– active part;
– inputs;
– oil expander or oil nitrogen expander;
– thermosiphon filter and fittings;
– protective devices;
– control devices.

The active part consists of a core, windings, and a high-voltage switch.
The skeleton consists of a magnetic circuit, the upper and lower yoke of which is tightened by yoke beams.
Three-core magnetic wire, charged from cold-rolled electrical steel. The upper yoke beams of the frame have an eyelet for lifting the active part.
Transformer windings are made of aluminum or copper wire.
The arrangement of windings is concentric. Voltage regulation is carried out using a high-voltage three-phase rail-type switch with a sliding contact.

Control and measuring devices:

To control the oil level, float or arrow oil indicators are installed on transformers. The oil indicator is mounted on the oil expander cover or on the tank wall in TMZ transformers.
There are three control marks on the oil indicator, which correspond to the oil level in the non-working transformer at different temperatures:
– minus 45 °C, plus 15 °C and plus 40 °C – implementation of U;
– minus 60 °C, plus 15 °C and plus 40 °C – execution of HL.
A control line corresponding to the oil level at the sealing temperature is marked on the oil indicator of the TMZ type transformer.
A float oil indicator is installed on TMG, TMGF type transformers.

Power oil transformers comply with: ГОСТ 15150-69, TУ У 27.1-40169080-006:2022 “General purpose power transformers with a voltage of up to 35 kV”