Nov 10, 2015

New Siemens Relay 7SR45 Argus!


iemens recently announced the launch of the new 7SR45 Argus digital relay. The digital protection relay 7SR45 was developed as a successor to the widely used 7SJ45 and becomes part of the 7SR Argus family. The overvoltage and earth fault relay, which is voltage-transformer-supplied, do not need any auxiliary voltage supply and are available in two different versions depending on the current transformer configurations (1A or 5A).

The new device is primarily intended for switchgear and has both, dependent and independent characteristics in the program. It allows high sensitivity with a minimum setting of 0.2 x In for phase overcurrent protection. The compact installation housing is equipped with front-mounted navigation buttons, LCD display and a front-end USB interface. Configuration and parameter changes can be made either via the front buttons or via the free Reydisp Evolution PC software. Here are the facts:

Protection functions:

  • instantaneous overcurrent phase (50)
  • instantaneous earth overcurrent, calculated (50N)
  • instantaneous earth overcurrent, measured (50G)
  • inverse time overcurrent phase (51)
  • inverse time earth overcurrent, calculated (51N)
  • inverse time earth overcurrent, measured (51G)
  • Quick release in case of switch on to failure (SOTF)
  • inrush stabilization

Main functions:

  • transformer supplied
  • 10 fault events
  • event list (until 100 events)
  • password protection
  • self-monitoring
  • overcurrent function
  • parameterizing with "Reydisp Evolution PC Software"
  • hi sensitivity (trip from 20% rated current possible)


  • 4 current transformer with 1 A- or 5 A-inputs
  • 2 binary inputs
  • 2 binary outputs (stored, 1 change over and 1 closer)
  • 1 impuls output

User interface:

  • 2-line LCD display with 16 characters, background lighted
  • navigation keys
  • 9 user-optimized preprogrammed LEDs

Practical experiences are not available. We are curious!