Switchgear and Protection (EE422)
Fuses and switches, methods of earthing, Circuit Breakers: Arcs, Interruption, RRRV, Current chopping, Interruption of capacitive current, Resistance switching. Types of circuit breakers, Circuit breaker ratings, Auto reclosure. Protective relaying: Functions, Standard definitions and terminology, Fundamental characteristics. Relay classifications, Electromechanical relays. Directional relay, Reverse power relay. Differential protection schemes for bus-bars, transformers and alternators. Frame leakage, bus-bar and transformer protection. Buchholtz relay, Backup protection. Alternator protection: Negative phase sequence relay, Loss of field protection. Line protection: Overcurrent relays and schemes, Distance relays and schemes, Effect of arc resistance, Translay relaying, Carrier current relaying. Induction motor protection: Abnormal operating conditions, Undervoltage, Phase and earth fault, Overload and unbalance voltage protection. Solid state relays: Comparators, Duality between phase and amplitude comparators. General equation of comparators, Realization of directional, Ohm, reactance, impedance and Mho characteristics using the general characteristic equation, Static distance relays. Computer aided relaying: Introduction to microcomputer based relays, General functional diagram of microcomputer-based relays.