Nature, causes and consequences of faults - Fault statistics - Need for protection - Essential qualities of protection - Types of protection – Primary and back up protection - Instrument Transformers - Basics of switchgear - Fuses, isolators, Earthing switches.
Development of protective relays - Recent developments - Operating principle - Classification of relays based on construction - Electromagnetic relays, Thermal relays, Overview of Static and Microprocessor relays, Numerical Relays - Introduction, Block diagram, Sampling theorem, Anti–Aliasing Filter, Least square method for estimation of phasor, concept of Discrete Fourier Transform to estimate the phasor.
Apparatus protection - Bus Bar protection, Transmission Line protection - realization of distance relays using numerical relaying algorithm, Introduction to wide area measurement (WAM) system - Generator protection - Motor Protection - Transformer Protection.
Overvoltage protection - Lightning arresters - Operating principle and types of arresters, Surge absorbers - Insulation co-ordination.
Circuit breakers - Operating principle - Arc phenomenon, principle, DC and AC Circuit Breaking - Problems of circuit interruption - Interruption of capacitive currents, Current chopping, Resistance Switching and methods of arc extinction - Arc interruption theories - Arc voltage, restriking voltage, Recovery voltage.
Types of circuit breaker – Construction and Operating Principle – HVDC circuit breaker - Selection of circuit breaker and its ratings - Auto reclosing