According to GOST 11677 (Interstate Standard 11677)
and IEC – 76 standards

Power down-step three–phase double winding for general purposes oil transformers power rating from 10 to 2500 kVA for voltage up to 10 kV are intended for national economy needs. Indoor and outdoor installation is possible.

Specification

ТМГ-10–2500 power transformers are manufactured with primary winding (HV) voltage rating up to 10 kV and secondary winding (LV) voltage rating up to 0.4 kV. Connection scheme and group are Y/Yn -0; D/Yn –11.

Voltage is regulated without excitation. Hence the transformers are equipped with HV tap changers, which are connected to the HV winding and allow voltage regulation on LV and HV side by ±2 х 2.5 % steps while the transformer is switched off the system.

Notation Conventions

ТМГ – Х/10 У(ХЛ)1,

Т – three–phase transformer,

Г – sealed,

Х – rated power, kVA,

10 – HV winding voltage rating, kVA,

У(ХЛ)1 – climatic modification and allocation category according to ГОСТ 15150-69.

Operating Condition

Altitude above sea level – up to 1000 m.

Temperature of ambient air:

• for temporary climate: from –45С to +40С (У modification);
• for cold climate: from –60С to +40С (ХЛ modification).

Relative air humidity not more than 80% at +25С.

Transformers are not to operate:

• in flammable and corrosive medium (containing gases, high concentration of dust, evaporations, etc.);
• in vibrating and shaking medium;
• at frequent switching on on feeding side (up to 10 times at 24-hour period).

Transformers construction

The ТМГ-10–250 transformers tanks of oval form and ТМГ-400–2500 of rectangular form are equipped with corrugated sidewalls without oil dilator. To lift the tank and the transformer ready-assembled there are hooks, which are situated under the upper frame of the tank. The lid of the tank is equipped with a cock (a plug) for filling with oil; there is a plug for draining the oil, a cock (a plug) for assaying, and a grounding bolt.

The active part consists of a magnetic core, which is made of cold-rolled electrotechnical steel, windings and a HV tap changer. The windings of the transformer are made of aluminium or copper.

The HV and LV inputs are dismountable, for outdoor installation; the insulators are bushing, made of porcelain. At incoming current of 1000 A and more a special terminal with a blade is fastened in the upper part of the current-carrying pivot. The terminal provides the connection with flat buses. The HV and LV inputs are located on the lid.

For oil level monitoring a floating-type oil level indicator is fastened onto the tank lid. For measurements of oil upper layer temperature in the tank a thermometer is fastened onto the transformer lid.

Oil dilatation which depends on transformer temperature is compensated with pressure change inside the tank at the expense of change of configuration and corrugated sidewalls volume.

In ТМГ sealed transformers oil does not contact with air and it does not oxidize. They do not need extra expenses when putting into exploitation and do not need preventive repairs and revisions during the operation period. There’s also no need in oil analyzing and regeneration.

Transformers with power rating from 160 to 2500 kVA are equipped with castors, which are used when transferring the transformer crosswise and lengthwise.