Non-directional overcurrent protection

Non-Directional Overcurrent Protection – Reyrolle 7SR45

Reyrolle 7SR45

The Reyrolle 7SR45 Argus self-powered/dual powered non-directional overcurrent and earth fault relay is developed using the latest generation of hardware technology and is available in multiple variants depending on the current transformer (CT), binary input/binary output, power supply, and communication configuration.

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Features & functions

Non-directional overcurrent protection Reyrolle 7SR45


The Reyrolle 7SR45 numeric relay provides both definite time and inverse time overcurrent and earth fault protection functions ensuring sensitivity with an operating setting range of 0.1 to 0.2 ⋅ I rated for phase overcurrent protection. The relay is CT powered with an option for connection to an external auxiliary supply to provide additional security and communications port for connecting to SCADA. The compact non-draw-out design provides front fascia to the navigation keys, LCD, and front USB port for ease of use


  • Self-powered / auxiliary powered

  • 10 fault records

  • 100 event records

  • Password protection

  • Self-monitoring

  • Overcurrent protection functions (instantaneous and delayed)

  • Relay integration via Reydisp Evolution PC Software

  • Sensitivity of 20% nominal current

  • Serial interface


  • 4 current transformer with 1 A or 5 A Inputs

  • Up to 4 binary Inputs and 4 binary outputs

  • 2 latched binary outputs, 1 changeover and 1 normally open

  • 1 pulsed output

  • 2 case options for mounting in various RMU's


User Interface

  • 16 character x 2 line backlit LCD
  • Menu navigation keys 
  • 4 User programmable LEDs for assigning protection functions & Phase Indications
  • 9 predetermined LED’s for easy use
  • Mechanical flag
  • Front USB interface
  • Optional rear RS485 communication port


Protection functions

  • 49 Thermal overload
  • 50 Instantaneous overcurrent - phase
  • 50G Instantaneous earth fault - measured
  • 50N Instantaneous earth fault - calculated
  • 51 Time delayed overcurrent - phase
  • 51G Time delayed earth fault - measured
  • 50LC Line check/switch onto fault (SOTF)
  • 51N Time delayed earth fault - calculated


Ancillary functions

  • 49T High speed external trip via binary input
  • 68 Protection function blocking/Inrush current blocking
  • 86 Lockout


  • IEC 60870-5-103