Decision Making in Protective Relays

  • Waldemar Rebizant
  • Janusz Szafran
  • Andrzej Wiszniewski
Part of the Signals and Communication Technology book series (SCT)


Having in mind that protective relays are devices that are supposed to evaluate the state of the protected plant and to react properly in case of abnormal operating conditions, the relay final output is usually the command to trip the protected element or to raise an alarm, whenever it is necessary. Before a tripping signal to the associated circuit breaker or an alarm is issued the decision is to be taken that is based on the locally measured criteria values and additional information from other protective relays and/or control centers. While in preceding chapters the measurement techniques and algorithms were presented, here the possible approaches to the decision making are outlined and the detailed decision procedures are described.


Decision Vector Sequential Probability Ratio Test External Fault Differential Curve Differential Protection 


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Copyright information

© Springer-Verlag London Limited  2011

Authors and Affiliations

  • Waldemar Rebizant
    • 1
  • Janusz Szafran
    • 1
  • Andrzej Wiszniewski
    • 1
  1. 1.Wroclaw University of TechnologyWroclawPoland

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