Electrical Energy Systems

At the end of the course, the student should be able to: 1. recognise the structure and operation of electricity generation, transmission and distribution systems and the impact on the society and environment; 2. solve problems involving modeling, design and performance evaluation of power transmission lines; 3. analyse power flow in power transmission networks and apply power flow results to solve simple planning problems; 4. calculate currents and voltages in a faulted power system under both symmetrical and asymmetrical faults, and relate fault currents to circuit breaker ratings; and 5. analyse the transient stability of simple power systems using equal area criterion.

Generation of electric energy: Sources of energy. Heat value of fuels. Thermal stations. Hydroelectric stations. Nuclear stations. Economics of power supply: Fixed and running charges in electric power production. Load curves and load duration curves including concept of base, intermediate and peak load. Definition of load factor, maximum demand, Diversity factor and their effects on generation. Distribution system: Survey of power system components: feeders, distributors, services mains, radial and ring-man systems. Voltage drop in distribution systems. Per-unit qualities. Overhead transmission system: Conductors and insulators. Transmission line parameters. Resistance, inductance and capacitance. Skin effect. Corona discharge. Stringing: Calculation of sag and tension. Stringing chart and performance. Representation of short and long power lines. Underground cables: Types. Inductance of concentric cables. Capacitance of single-core and three-core cables. Thermal characteristics. Sheath currents. Circuit breakers: Principles of arc-extinction. Types of circuit breakers. Current growth in a purely inductive circuit. Interpretation of circuit breakers lest oscillographs. Current chopping. Resistance and capacitance switching. Breaking and making currents.