Feeder protection

Medium voltage feeders demand high-speed fault clearance and selective coordination with upstream and downstream protection. Feeder protection ensures reliable operation under varying network topologies and supports automation functions like remote switching, fault location and automatic reclosing. Protection must handle short circuits, earth faults, and overloads efficiently.

Common Feeder protection functions:

  • ANSI 50/51              overcurrent protection
  • ANSI 67                    directional overcurrent
  • ANSI 50G, 67G       (directional) ground current
  • ANSI 21                    distance protection
  • ANSI 21FL               fault locator
  • ANSI 59/27             overvoltage/undervoltage
  • ANSI 50BF                breaker failure
  • ANSI 87LD                line differential protection
  • ANSI 79                     automatic reclose
  • ANSI 78 and 81R    vector surge and ROCOF (for power plant connection point)
  • SOTF                          switch-on-to-fault

For feeder protection, following product options are recommended: