Aims & Learning Objectives:
To provide a basic understanding of the way in which a.c. electrical machines, power systems andpower electronic devices operate. On completion of the unit students should be able to: describe the structure of a modern power system and its major components, perform simple 3-phase calculations, explain the need for, and provision of, control in a power system; describe the construction, action and characteristics of the principal types of a.c. machine and perform simple analyses; explain the basic operating principles and perform simple analyses of common power-electronic systems including line-frequency rectifiers, d.c. to d.c. converters and d.c. to a.c. inverters.
Single and 3-phase transformers: construction, operation, connections, models. Three-phase induction machines: construction, operation, equivalent circuits, characteristics. Three-phase synchronous machines: construction operation and action of round rotor, type; equivalent circuits, phasor diagrams. Simple power system economics, the need for transmission and distribution systems, energy conversion, energy consumption, introduction to 3-phase theory, power engineering conductors and insulators, power system control, faults and protection systems. Power semiconductor devices; introduction to the conduction, switching characteristics and drive requirements of diodes, thyristors and power transistors. Line frequency power converters; introduction to single and three-phase rectifier circuits operating with resistive and inductive loads. d.c. to d.c. power converters; introduction to switched mode power supplies and the principles of operation of step-down and step-up converters.