MB140 Series

Part of the 140 platform, the MB140x feeder management relays provide an integrated solution for the complete protection, control and monitoring of overhead lines and underground cables, covering all distribution voltage levels.

Providing all essential information to efficiently maintain complex power systems and their components, the MB140x relay family is user-friendly, allowing application on any electrical network.

The MB140x is a feeder management relay platform with over current and earth fault protection, as well as auto reclose and a full suite of protection, control and monitoring functions.

The platform also provides main or back-up protection for MV, solidly earthed, and isolated neutral systems.

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Key benefits:

  • Full feeder management with efficient monitoring, control, recording and digital communications

  • Supports major digital control system protocols for integration into DCS, SCADA and engineering workstations.

  • Harsh environment protection extends the life of the product.


  • 3-stages of non-directional over current, earth fault, sensitive earth fault protection

  • Negative phase sequence over current, Broken conductor, Breaker fail protection.

  • Auto reclose & Cold Load Switching Feature.

  • TCS, CB Monitoring, Max Current Demand Supervision functions.

  • IEC 61850 with Rear FO Port, Modbus RTU or IEC60870-5-103 with RS 485 Rear Port for Remote Communication.

  • Front USB Port for User interface.

Special Application:

  • Auto reclose function offers multi shots reclosing to avoid discontinuity during transient fault tripping in transmission lines.

  • The standard curves offers reliable fault tripping, without constraining circuit loadability

  • Cold Load Switching feature avoids protection relay tripping due to inrush current, when a distribution circuit is re-energized following an extended outage.

Device Number Function
79 Auto reclose
86 Latching/Lockout Contacts
50BF CB Failure
CLP Cold Load Pick Up
TCM Trip Circuit Monitor
50N Earth Fault Definitive Time Over current
51N Neutral/Ground IDMT Over current
SEF Sensitive Earth Fault
50 Phase Definitive Time Over current
51 Phase Inverse-Time Over current
TRIP / CLOSE breaker control switches with necessary interlock logics with simple MIMIC showing breaker status.

TRIP LOCK facility with password Protection for Line clear / breaker


LOCAL / REMOTE switch function with Password Lock.

AUTO Breaker Maintenance annunciation.

Built in ANNUNCIATOR for TRIP and NONTRIP functions with ACCEPT / RESET push buttons and test LED facility.

Built in Trip Circuit Supervision.

Built in breaker ANTIPUMPING logic.

Built in CLOSE / TRIP interlock logics.

DC supply supervision.

34 INDICATING LEDs includes DC healthy, Trip circuit fail, Breaker ON / OFF status, Remote / Local operations, spring charge, Breaker in service status etc., –

14 Digital inputs that includes inputs for Bucholz alarm, Oil temperature alarm , Winding temperature alarm, and Bucholz Trip, Oil temperature Trip, winding temperature Trip functions of Power Transformer.

MASTER TRIP relay function

Device Healthy feature to give alarm with different supply / device failure.

Control button status information in LCD panel.

Dedicated three phase voltage indicator (MVIL3) with LED indicators directly energized from the PT supply, indicating the status of High voltage without depending on dc supply for safety.(optional)

Three Phase & Earth Fault Over current protections With Three stages of settings- Low set, wide set, High set (True RMS measurement).

User Friendly settings with Password Protection.

16 Characters 2 Line LCD display with backlight – alphanumeric display.

1Amp & 5 Amp CT secondary selectable by software

Aux voltage : 24, 30, 48, 110 or 220 Vdc.

DC transient free instantaneous High set with operating time <15 milliseconds @5times the setting. (Takes care of CT saturation)

Self Monitoring.

Reset time feature for flashing faults

Two group of protection settings

Primary as well as secondary current Metering

Cold load Switching

Multi shot Auto recloses.

Trip circuit supervision.

Circuit Breaker failure protection.

Circuit Breaker monitoring.

External blocking feature.

8 fault records with time stampings.

Maximum current demand.

Feeder identification.

Relay / LED test facility

100 fault records with time stampings.

100 Event records with time stampings.

RS485 and USB port Communication with MODBUS or IEC 60870-5-103


MB140x PC STUDIO is a PC tool for configuring M140C and M140D relays that assemble all tools in a palette for simple entry, with intuitive navigation via fewer mouse-clicks.

Key benefits / features in the MB140x PC STUDIO family

  •  Powerful free of charge PC interface tool
  •  Intuitive and versatile interface with file management facilities
  •  Real-time measurement visualization
  •  Integrated configuration and monitoring features
  •  Send and extract setting files
  •  Event and disturbance record extraction and analysis