NA11

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.

FUNCTIONS

Standard Protective & control elements
  • Phase overcurrent side H and side L
  • Maximum Residual Overcurrent
  • Automatic Recloser
  • Breaker Failure
SW Pack optional configuration
  • Thermal with Pt100 Probes



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