The complete double-transformer (2КТПА) substations with emergency supply inputs are designed for reception, conversion and distribution of three-phase AC electric power with frequency 50 Hz and are intended for the first category and special reliability group consumers’ supply (auxiliaries of gas-transfer compressor stations of gas-main pipelines). The 2КТПА double-transformer substations are assigned for indoor installation and can be operated in temporary climate conditions (from -20С to +40С).

The substation includes:

• An input device on the HV side:
• single-ended switchboard of ВВ-1 type (cable input cubicle);
• a switchboard with the ВНПР load-breaker with a spring-rod drive of the ШВВ-2Р type.
• Power transformers (2 pcs):
• oil ТМЗ-630, ТМЗ-1000;
• dry ТСЗГЛ-630, ТСЗГЛ-1000.
• The РУНН distribution device on the LV side, which consists of:
• LV input switchboards (ШВ);
• sectional switchboards (ШС);
• outgoing lines switchboards (ШЛ);
• relay equipment switchboards;
• emergency input from the generator switchboards (ШВА);
• bus-bar wires;
• dispatcher's supervision board;
• accounting switchboard.

The number of switchboards is defined by the request, but no more than 13 (34 outgoing lines) and no less than 10 (19 outgoing lines). The 2КТПА is delivered by vehicular blocks up to 4 m long.

The ШВ switchboard enables the possibility of the ШМА-16 bus-bar wires connection.

There is also a possibility of connection up to 6 (ШВ and ШС) and up to 9 (ШЛ) cables with diameter up to 3x150 sq. mm. with dry termination. In the ШВА switchboard – up to 5 cables with diameter up to 3x185 sq. mm.+1х70 sq.mm.

The input, sectional and emergency breakers are controlled from a separate control panel.

The РУНН switchboards are produced with automatic circuit-breakers of the telescopic type.

To meet the customer’s requirement, the КТП can be completed with automatic circuit-breakers produced by «Schneider Electrik», «АВВ», «Siemens», etc. according to individual schemes and questionnaires.

In the КТПА the БМР3-0,4 microprocessor unit is used. It can be connected to the automatic control system.

The РУНН main circuit scheme is given in the figure. It gives the possibility of two variants of AC emergency power supply connection. The emergency power supply is connected to both of the РУНН sections or separately to each with using one or two AC respectively. The 2КТПА schemes provide the sectional breaker and emergency power supply system with the АВР with automatic return of the scheme to the initial condition when the main power supply is restored.