Power protection

1. Overcurrent Protection  2.Thermal Overload Protection  3.Unbalanced Load (Negative Sequence) Protection  4. Dead machine Protection 5.Differential Protection 6.Underexcitation  Protection  7. Reverse Power Protection  8. Forward Active Power Supervision  9. Impedance Protection  10. Out-of-Step Protection  11. Undervoltage Protection  12. Overvoltage Protection  13. Under/Over Frequency Protection  14. Overexcitation (Volt/Hertz) Protection  15. Rotor Earth fault protection 16. Stator Earth fault protection 17.Generator Inter trun protection

 There are three type of generator protection 1.Class A: When any severe  fault occur in    generator/generator transformer/Unit auxiliary transformer than generator protection system give the trip command to generator circuit breaker,GT breaker  and field breaker simultaneously. 2.Class B  In class B trip protectionWhen the fault occur in generator  which not need to required immediate isolation of generator from the  grid. In this class the turbine trip first than after some time delay the generator circuit breaker,GT breaker and field breaker trip.so that the trap steam in turbine properly used. 3.Class C When the fault occur outside the GT unit ,only Generator transformer circuit breaker trip and unit not synchronised with grid but generator provide the power for  house load of plant.