Generator protection

Generators represent highly valuable assets in electrical power systems. Their failure due to faults leads to an interruption in the power supply, potentially with far-reaching effects on downstream systems. Protection systems protect these components from the effects of electrical faults, mechanical faults and system disturbances ensuring reliable continued power supply to unaffected loads.

Typical generator protection includes:

  • ANSI 24                 overexcitation (V/Hz)
  • ANSI 25/25A        synchro-check and automatic synchronizing
  • ANSI 27/59           undervoltage / overvoltage
  • ANSI 27T               time-dependent undervoltage
  • ANSI 27Q              reactive power / undervoltage
  • ANSI 32                 reverse / directional power
  • ANSI 32N/G         zero sequence power
  • ANSI 40                 loss of excitation
  • ANSI 46                 negative phase sequence
  • ANSI 47                  negative phase sequence voltage
  • ANSI 49                  thermal protection
  • ANSI 50/51           overcurrent
  • ANSI 50G, 67G     (directional) ground current
  • ANSI 59T                time-dependent overvoltage
  • ANSI 78/78PS       vector surge and pole slip
  • ANSI 81/81R         frequency and RoCoF protection
  • ANSI 87                  generator differential

Generator protection can be effectively realized using following models: