Protection and Switchgear

angle arc extinction armature breakdown Buchholz relay busbar C.T. secondaries capacitance capacitor characteristics component connected current flows current transformers current zero delta delta connected diagram dielectric strength differential protection differential relay directional disc earth fault protection earthing resistance electrode electromagnetic element equipment fault current fault occurs Fixed contact flux ground fault ground wire Hence high voltage impedance relay increases insulation interruption lightning arrester lightning strokes load magnet maximum motor moving contact negative sequence neutral normal oil circuit breaker operating coil overcurrent relay overhead line overvoltages phase fault phasor power transformer pressure primary produced Protection and Switchgear protection scheme protective relaying protective zone rated reactance recovery voltage relay coil relay operates resistor restraining coil restriking voltage rotor RRRV secondary currents short circuit shown Static Relays stator surge switch system voltage torque transient transmission line trip circuit trip coil value of earthing