Multifunction protection with synchronization

Multifunction protection with synchronization – SIPROTEC 7SJ64


The SIPROTEC 7SJ64 can be used as a protective control and monitoring relay for distribution feeders and transmission lines of any voltage in networks that are earthed (grounded), low-resistance earthed, unearthed, or of a compensated neutral point structure. The relay is suited for networks that are radial or looped, and for lines with single or multi-terminal feeds. The SIPROTEC 7SJ64 is equipped with a synchronization function which provides the operation modes ‘synchronization check’ (classical) and ‘synchronous/asynchronous switching’ (which takes the CB mechanical delay into consideration). Motor protection comprises undercurrent monitoring, starting time supervision, restart inhibit, locked rotor, load jam protection as well as motor statistics.

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Features & functions

Multifunction protection with synchronization SIPROTEC 7SJ64


The SIPROTEC 7SJ64 is featuring the "flexible protection functions". Up to 20 protection functions can be added according to individual requirements. Thus, for example, rate-of-frequency-change protection or reverse power protection can be implemented. 
The relay provides easy-to-use local control and automation functions. The number of controllable switchgear depends only on the number of available inputs and outputs. The integrated programmable logic (CFC) allows the user to implement their own functions, e.g. for the automation of switchgear (interlocking). CFC capacity is much larger compared to SIPROTEC 7SJ63 due to extended CPU power. The user is able to generate user-defined messages as well. 

The flexible communication interfaces are open for modern communication architectures with control systems.



  • 4 current transformers

  • 4 voltage transformers

  • 7 to 48 binary inputs

  • 5 to 21 output relays
  • Up tp 4 high-duty relays
  • Text display or graphical display
  • Flush-mounting housing, surface-mounting or detached display

Communication interfaces

  • System port 
    – IEC 61850


    – DNP3 TCP

    – IEC 60870-5-103 
    – DNP 3.0


  • Service port
    – DIGSI 4,
    – Modem
    – Thermobox
  • Additional port
    – Thermobox
  • Front port

    – DIGSI 4

  • Time synchronization via IRIG B/DCF77


Protection functions

  • Overcurrent protection
  • Directional overcurrent protection

  • Sensitive dir./non-dir. earth-fault detection

  • Displacement voltage

  • Intermittent earth-fault protection

  • Directional intermittent ground fault protection

  • High-impedance restricted earth fault

  • Inrush restraint

  • Motor protection

  • Overload protection

  • Temperature monitoring

  • Under-/overvoltage protection

  • Under-/overfrequency protection

  • Rate-of-frequency-change protection

  • Power protection (e.g. reverse, factor)

  • Undervoltage-controlled reactive power protection

  • Breaker failure protection

  • Negative-sequence protection

  • Phase-sequence monitoring

  • Synchronization

  • Auto-reclosure

  • Fault locator

  • Lockout

Control functions/programmable logic

  • Flexible number of switching devices

  • Position of switching elements is shown on the graphic display

  • Local/remote switching via keyoperated switch

  • Control via keyboard, binary inputs, DIGSI 4 or SCADA system

  • Extended User-defined logic with CFC (e.g. interlocking)

Monitoring functions

  • Operational measured values V, I, f,...

  • Energy metering values Wp,Wq

  • Circuit-breaker wear monitoring

  • Slave pointer

  • Trip circuit supervision

  • Fuse failure monitor

  • 8 oscillographic fault records

  • Motor Statistics


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