B-35 Autotransformer Protection Cabinet

The cabinet is designed for protecting 35/6kV autotransformers and includes:

  • Transformer differential current protection;
  • Zero-sequence current protection;
  • Overcurrent protection for high, medium and low voltage sides;
  • Circuit breaker failure protection (CBFP) terminal action for autotransformer tripping; 
  • Oil temperature monitoring;
  • Over/under voltage protection;
  • Over/under frequency protection;
  • Overload protection;
  • Receiving signals from gas protection alarm/trip stages, oil temperature/level sensors, cooling system faults;
  • Automatic reclosing (AR);
  • Two-channel trip circuit monitoring;
  • Protection device health monitoring;
  • Discrete and analog event recording.

The cabinet's AC circuits provide connection to main CT secondary circuits with 1A or 5A rated current.

Functional Composition:

  • Current measurement circuits; 
  • Voltage measurement circuits; 
  • Protection input/output circuits; 
  • Relay control circuits; 
  • Lighting and power outlet circuits.

 

 

Technical Specifications:

Parametr Value
Power Supply Parameters
Operational voltage U 220V DC
Light Circuit 
AC voltage rating 220V
Frequency rating 50Hz
Measurement Circuits
Rated current 5А
Rated line voltage  100V
Communications
Interface RS-232 (Digsi)
Protocol IEC 60870-5-103
General Characteristics
Ambient temperature (20 ± 5) °С
Relative humidity ≤80%

Cabinet Design

The cabinet features a grounded metal enclosure (OPTIMA frame, RAL7035 color) with two-sided access - transparent front door and solid rear door. All metal components are corrosion-protected with epoxy-polyester powder coating. Insulating materials are flame-retardant. Complies with ST RK GOST R 51321.1 (IEC 60439-1-92).