Slip protection: Under normal condition the generator is synchronized with grid. But during some extreme fault condition such as heavy line fault, lightning impulse, switching transient etc. the heavy transient torque may be subjected to the generator winding. Due to that the generator may loss its synchronism and Pole slipping occurs. Pole slipping is nothing but a generator’s rotor produces weak magnetic field or low excitation for the given input or the physical slip occurs in the rotor’s shaft. It can cause severe mechanical stresses within the rotor experiences a sudden physical and electrical shift in position relative to the stator, putting winding at risk, causing shaft damage etc. after which the field recovers enough strength to lock the rotor back in sync with the stator. But the recovery time delay exceeds the safe limit, there is high currents flow in the generator windings which can cause thermal instability and winding stresses, pulsation torques and mechanical resonances that have the potential danger to turbine generator.