Bay controller

Bay controller - SIPROTEC 6MD66 - side view

SIPROTEC 6MD66 (phase-out product)

The 6MD66 high-voltage bay control unit is the control unit for high voltage bays from the SIPROTEC 4 relay series. Because of its integrated functions, it is an optimum, low-cost solution for high-voltage bays. The 6MD66 high-voltage bay controller unit also has the same design (look and feel) as the other protection and combined units of the SIPROTEC 4 relay series. Configuration is performed in a standardized way with the easy-to-use DIGSI 4 configuration tool. For operation, a large graphic display with a keyboard is available. The important operating actions are performed in a simple and intuitive way, e.g. alarm list display or switchgear control. The operator panel can be mounted separately from the unit, if required. Thus, flexibility with regard to the mounting position of the unit is ensured. Integrated key-operated switches control the switching authority and authorization for switching without interlocking. High-accuracy measurement (± 0.5 %) for voltage, current and calculated values P and Q are another feature of the unit.

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Features & functions

Bay controller SIPROTEC 6MD66 (phase-out product)


  • Integrated synchro-check for synchronized closing of the circuit-breaker
  • Breaker-related protection functions (Breaker Failure 50BF, Auto-reclosure 79)
  • Automation can be configured easily by graphic means with CFC
  • Flexible, powerful measured-value processing
  • Connection for 4 voltage transformers, 3 current transformers, two 20 mA transducers
  • Volume of signals for high voltage
  • Up to 14 1 ½-pole circuit-breakers can be operated
  • Up to 11 2-pole switching devices can be operated
  • Up to 65 indication inputs, up to 45 command relays
  • Can be supplied with 3 volumes of signals as 6MD662 (35 indications, 25 commands), 6MD663 (50 indications, 35 commands) or 6MD664 (65 indications, 45 commands); number of measured values is the same
  • Switchgear interlocking
  • Inter-relay communication with other devices of the 6MD66 series, even without a master station interface with higher level control and protection
  • Suitable for redundant master station
  • Display of operational measured values V, I, P, Q, S, f, cos (power factor) (single and three-phase measurement)
  • Limit values for measured values
  • Can be supplied in a standard housing for cubicle mounting or with a separate display for free location of the operator elements
  • 4 freely assignable function keys to speed up frequently recurring operator actions

Communication interfaces

  • System interface
        - IEC 61850 Ethernet
        - IEC 60870-5-103 protocol
        - PROFIBUS-FMS/-DP
        - Service interface forDIGSI 4 (modem)
        - Front interface forDIGSI 4
        - Time synchronization via IRIGB/DCF77

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