Feeder protection

The relay type NA11 can be used in radial networks as feeder or power transformer protection. In solidly grounded systems the residual overcurrent protection can be used on feeders of any lenght, while in ungrounded or Petersen coil and/or resistance grounded systems, the residual overcurrent protection can be used on feeders of small lenght in order to avoid unwanted trippings due to the capacitive current contribution of the feeder on external ground fault. Beside to the phase and residual overcurrent protections, the automatic reclosing function is provided. The NA11 device may be shipped with traditional CTs or with low power (LPCT) current inputs.


Standard Protective & control elements
  • Phase overcurrent side H and side L - 50/51
  • Maximum Residual Overcurrent - 50N/51N
  • Automatic Recloser - 79
  • Breaker Failure - BF
SW Pack optional configuration
  • Thermal with Pt100 Probes - 26


  • One USB Type B local port for communication with ThyVisor setup software




XMR-A is a part of XMORE platform, the complete range of IEDs for Medium Voltage application includ ...


The relay type NA10 is typically used in radial HV, MV and LV networks as feeder or power transform ...