Power protection

  Knee point voltage of current transformer secondary side, the value of voltage at which when the applied across current transformer secondary side   is increased by 10 percent, causes the exciting current to increase by 50 percent.

 Goose in numerical relay used to share the signal between two numerical relay at comman network.

 There is no zero sequence current in delta winding line of transformer.so for protect star delta three phase  Transformers from external fault zero sequence current compansation must we used in differential protection scheme (87T).

 Step1 Press the enter and go to setting 2 Step2 Enter password 0000 Step3 Change the CT & PT primary and secondary ratio. After that press the enter and press exit button.

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.