Principles and need for protective schemes – nature and causes of faults – types of faults – fault current calculation – Zones of protection and essential qualities of protection – Methods of Neutral grounding

Operating principles of relay - Torque equation – R-X diagram – Electromagnetic Relay – Over current, Directional, Distance, Differential, Negative sequence and Under frequency relay

Application of Current transformers and Potential transformers in protection schemes –Sources of error. Protection of transformer, generator, motor, bus bars and transmission line

Static relays – Phase, Amplitude Comparators – Synthesis of various relays using Static comparators – Block diagram of Numerical relays – Over current protection, transformer differential protection, distant protection of transmission lines

Physics of arcing phenomenon and arc interruption - DC and AC circuit breaking – re-striking voltage and recovery voltage - rate of rise of recovery voltage - current chopping - interruption of capacitive current - resistance switching- Types of circuit breakers – air, oil, SF6 and vacuum circuit breakers – comparison of different circuit breakers – Rating and selection of Circuit breakers