Power System Faults: Analysis & Protection

Symmetrical Components: Significance of positive, negative and zero sequence components, Average 3- phase power in terms of symmetrical components, sequence impedances and sequence networks. Fault Calculations: Fault calculations, sequence network equations, single line to ground fault, line to line fault, double line to ground fault, three-phase faults, faults on power systems, faults with fault impedance, reactors and their location, short circuit capacity of a bus.

Introduction, Need for load flow, load dispatch centers and operating strategies, Formation of ZBUS and YBUS, development of load flow equations, load flow solution using Gauss-Seidel and Newton-Raphson method, Comparison of Gauss-Seidel and Newton-Raphson Method, fast decoupled method, introduction to forward backward sweep load flow for radial network.

Power flow through a transmission line, Stability and Stability limit, Steady state stability study, derivation of Swing equation, transient stability studies by equal area criterion. Factors affecting steady state and transient stability and methods of improvement.

Need for Protective systems, Evolution of protective relays - Zones of protection - Primary and Back -up Protection - Essential qualities of Protection - Classification of Protective schemes Basic Terminology: Relay, Energizing Quantity, setting, Pickup, drop out, Flag, fault clearing time, Relay time, Breaker time, Overreach, Underreach; Classification of Relays according to applications, according to time. Over current Relay, Distance Protection, Differential Protection. Relays: Operating Principle of a general relay, Electromagnetic, attracted and induction type relays, thermal relay, gas actuated relay, design considerations of electromagnetic relay. over current relays, directional relay, distance relays, differential relays. Relay Application and Characteristics.

Types & detection of faults and their effects, alternator protection scheme (stator, rotor, reverse power protection etc.) - Power transformer protection (external and internal faults protection), generator- transformer unit protection scheme, bus bar protection - Transmission line protection (current/time grading, distance), Pilot relaying schemes, power line carrier protection. Circuit Breakers: Classification, Arc Phenomenon, Arc Extinction and its Methods, Restriking Voltage & Recovery Voltage.