Generator Protection - ERPC

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Copyright @ Power Research & Development Consultants Pvt. LtdGenerator Protection1Copyright @ Power Research & Development Consultants Pvt. Ltd2Generator Protection -Introduction Size of individual generating unit 30 MW to 500/1000 MW Loss of even a single unit is a serious problem Consequence : Protection systems of such generators have also become more stringent Required to reduce the outage period to a minimum Achieved by rapid discriminative clearance of all fault conditions associated with the units Damage due to faults is none or to the minimumCopyright @ Power Research & Development Consultants Pvt. Ltd3Aspects of Generator ProtectionFault Classification Internal faults Abnormal Service conditions External Faults (as back up Protection ) The hazards and problems considered Phase to phase faults in winding Phase-ground faults in winding Ground faults in the rotorCopyright @ Power Research & Development Consultants Pvt. Ltd4Abnormal Conditions Loss or insufficient excitation Overload Overvoltage Under and Over frequency Unbalance current Inadvertent energization Out of step (loss of synchronism) Loss of prime mover (motoring)Copyright @ Power Research & Development Consultants Pvt.

losses in the generator and the prime mover, the generator starts to work as a synchronous compensator, taking the necessary active power from the network In case of steam turbines, a reduction of the steam flow reduces the cooling effect on the turbine blades and overheating may occur For thermal units, this setting is normally 1%

  Generators, Steam