To provide the student with a detailed knowledge of single and three phase electrical supply systems and machines. Students will be able to implement, analyse, fault find and report on single and three phase systems and machines.
Power Generation, Transmission and Distribution
Overview of the national generation, transmission and distribution systems. Network Regulation. Market deregulation and access to grid. Connection of renewable technologies to the national grid. Transmission system: Overhead lines, ratings and types. Underground cables. Transmission voltage levels. Substation layout and switching arrangements. Distribution system. Distribution system voltages. Final distribution transformers. LV distribution to consumers. Connection requirements. Consumer safety.
A.C. Circuit Theory
Generation of alternating EMF. Average, rms and max values of waveform. Frequency. Electrical supply network. Principle of simple DC generator. Principle of simple AC generator. Definition of cycle, period, frequency and amplitude of sinusoidal waves. Equation of sinusoidal waves in the time domain and the concept of phase shift. Phasor representation of sinusoidal waves. Characteristics of passive components in ac circuits. Concept of reactance and impedance of passive components. Analysis of series and parallel RL, RC and RLC ac circuits using complex numbers in rectangular and polar forms. Series and parallel resonance in RLC circuits. RC and RL transient analysis.
Single Phase AC Circuits
Calculation of currents, voltages, power and power factor in single phase AC circuits. Solutions using phasor diagrams and complex numbers.
Three Phase AC Circuits
Star and delta connections. Three phase, three wire and three phase, four wire systems. Relationships between line and phase quantities. Calculation of currents, voltages, power and power factor in three-phase systems. Energy monitoring tools and practices. Measurement of active and reactive power. Power factor correction.
Single Phase AC Machines
Construction and principle of operation of different types of single phase induction motors. Split phase, Capacitor start and Universal motor. Typical ratings and application of single phase motors. Energy efficient motors and controls. New and emerging technologies.
Three Phase AC Machines
AC induction motor: principle of operation, rotating field produced by stator windings, resulting torque on rotor, concept of slip. Torque / slip curves. Construction of stator and squirrel cage rotor. Effect of rotor resistance and reactance on torque. Description and use of wound rotor induction motor. Starting methods, Speed control, inverters, variable speed drives. Power factor, efficiency, starting torque and current.
Transformer principles. Ideal transformer calculations. Transformer ratios. Magnetising current, iron and copper losses. Regulation and efficiency. Construction of power transformer. Three phase transformers. Instrument transformers.
Commutating devices, inter-poles, armature reaction. Equation for generated emf. Comparison of lap and wave windings. Equation of motor torque and speed. Characteristics of series, shunt and compound connections and applications. Use for speed control. Thyristor control. Speed drives for DC motors. Braking. Stepper motors: Principle of operation, types of stepper motor, drive circuits, applications.
|Module Content & Assessment