POWER ELECTRONICS

UNIT I: Thyristor Silicon controlled rectifier (SCR), construction and principle of operation, two-transistor analogy, static and dynamic characteristics, gate characteristics, ratings, series and parallel operation of SCRs, over voltage and over current protections, protection against high di/dt and high dv/dt, use of UJT for pulse generation. UNIT II: Phase Controlled Rectifiers Principle of phase...

POWER SYSTEM PROTECTION & SWITCHGEAR

UNIT-I REALY: Terminology, Basic circuit, realy connection with trip circuit and circuit breaker, objectives of protection, types of relay, construction and operation of instantaneous over current realy. I.DM.T. Relay, directional Unit, differential relay, percentage differential relay, Buchholz relay, Generalized torque expression, logical construction of impedance reactance, MHO and Off-set MHO...

POWER SYSTEM ANALYSIS

UNIT I: Symmetrical three-phase short circuit on power systems, calculation of interrupting capacity of circuit breakers, current limiting reactors, symmetrical components, synthesis of unbalanced phasors from symmetrical components, representation of phase variables voltage, current and power in terms of symmetrical components, sequence impedances of power system elements, sequence networks of power...