Line differential protection for two line ends

Line differential protection for two line ends – SIPROTEC 7SD610

SIPROTEC 7SD610 (phase-out product)

The SIPROTEC 7SD610 relay is a differential protection relay suitable for all types of applications and incorporating all those functions required for differential protection of lines, cables and transformers. Transformers and compensation coils within the differential protection zone are protected by means of integrated functions, which were previously to be found only in transformer differential protection. It is also well-suited for complex applications such as series and parallel compensation of lines and cables. 

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Features & functions

Line differential protection for two line ends SIPROTEC 7SD610 (phase-out product)


It is designed to provide differential and directional back-up protection for all voltage levels and types of networks. The relay features high speed and phase-selective short circuit measurement. The unit is thus suitable for single-phase and three-phase fault clearance.


Digital data communication for differential current measurement is effected via fiberoptic cables, networks or pilot wires connections, so that the line ends can be quite far apart. The serial protection interface (R2R interface) of the relay can flexibly be adapted to the requirements of all existing communication media. If the communication method is changed, flexible retrofitting of communication modules to the existing configuration is possible. Apart from the main protection function, i.e. the differential protection, the SIPROTEC 7SD610 has a full range of configurable emergency and / or back-up protection functions such as phase and earth overcurrent protection with directional elements if voltage transformers are connected. Overload, under and over-voltage/frequency and breaker failure protection round off the functional scope of the SIPROTEC 7SD610.



  • Binary inputs: 7
  • Binary outpurs: 5
  • Text display
  • Surface-mounting or flush-mounting housing

Communication interfaces

  • System port 
    – IEC 61850

    – IEC 60870-5-103 
    – DNP 3
    – Modbus

  • Service port
    – DIGSI 4
    – Modem
  • 1 serial protection data interface
  • Front port
    – DIGSI 4
  • Time synchronization via IRIG B, DCF 77 or system interface


Protection functions

  • Differential protection for universal use with power lines and cables on all voltage levels with phase-segregated measurement (87L)

  • Two line ends capability

  • Suitable for transformers in protected zone (87T)

  • Restricted earth-fault protection (87N) if a transformer is within the protection zone

  • Well-suited for serial compensated lines

  • Two independent differential stages: one stage for sensitive measuring for high resistance faults and one stage for high current faults and fast fault clearance

  • Breaker-failure protection (50BF)

  • Phase and earth overcurrent protection with directional element (50, 50N, 51, 51N, 67, 67N)

  • Phase-selective intertripping (85)

  • Overload protection (49)

  • Over/undervoltage protection (59/27)

  • Over/underfrequency protection (81O/U)

  • Auto-reclosure single/three-pole (79)

Control functions

  • Command inputs for control of CB and disconnectors (isolators)

Monitoring functions

  • Self-supervision of the relay

  • Trip circuit supervision (74TC)

  • 8 oscillographic fault records

  • CT-secondary current supervision

  • Event logging / fault logging

  • Switching statistics

Front design

  • User-friendly local operation

  • PC front port for convenient relay setting

  • Function keys and 8 LEDs for local alarm


  • Browser-based commissioning tool

  • Direct connection to digital communication networks


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