27,5-35kV Three-phase oil-immersed power transformer ТМН type

 Transformers are suitable for indoor and outdoor use in the following conditions:
- altitude up to 1000 m;
- Climate environment: temperate (У1) and cold (УХЛ1);
- Operation temperature range: from -45°C (-60°C) to + 40°C.
Transformers are not suitable for use in the following conditions:
- In explosive and corrosive medium (containing gases, vapors, dusts and others an increased concentration);
- Vibration or shock;
- With frequent reconnections on the supply side.
The transformer provides voltage regulation.
The transformer provides the ability of voltage adjustment. The adjustment kind is tap changer РПН (on-load), i.e. switching transformer to another adjustment point is made operational.
Transformers are equipped with:
- Oil-level indicator, oil level in the tank;
- Level indicators, to monitor the level of oil in the tap changer compartment;
- Transformers temperature sensor (for transformer, 1000 kVA or more);
- Tap changers temperature sensor;
- Buchholz sensor (gas relay) of the transformer, for visual control of the released gas, as well as sampling of oil;
- Gas relay for the tap-changer;
- A device for rolling a transformer in longitudinal and transverse direction.

Transformers consist of an active part mounted under the cover and welded rectangular tank. HV and LV inputs, expander with oil-level indicator are located on the cover.
The active part consists of a magnetic core with windings, the upper and lower yoke beams, the tap changer. The transformers magnetic system is the stick-type, going from cold-rolled electrical steel.
The design of the transformer windings is cylindrical reel, screw-shape, depending of the transformers rated power and voltage.
The HV winding adjustment taps are connected to the fixed contacts of the switch mounted above the active part.

The transformers correspond to ГОСТ 11677 and ГОСТ 11920.