This thesis describes an adaptive protection scheme that performs the collection of the voltage and current phasors during post-fault period, tracking the power swing phenomena, identifying the onset of instability, and then issuing a stabilizing command. In this work, the protection system is to maintain the reliability! ensure the secure operation, and prevent total collapse of the power system. The work is based upon methods of clustering for meter placement in a bulk power system, and selecting the pilot points for installing the phasor measurement units (PMU) to measure the bus voltage phasors and associated branch current phasors. According to the network law, fast calculation of state estimation can be made from these measurements. Because the on-line assessment of transient stability has to provide a quick and approximate result, the direct method which determines stability without explicit integration techniques is applicable in this study. The results of the system stability prediction in real-time by digital computer simulation under stable and unstable operating conditions are presented. / Master of Science

Methods of analysis and important design considerations for distributed power systems (DPS) are addressed. A generalized analysis of subsystem interaction is presented. Emphasis is placed on absolute stability and eigenvalue location of the integrated system. Terminal properties of the decoupled subsystems are used in determining the stability criteria. Either analytical models or empirical data may be used in the interaction analysis. Design of EMI filters for a two-stage DPS is comprehensively discussed. A detailed analysis of the effects of input filters on current-mode controlled single-module regulators is given. It is shown that the criteria used to minimize filter interaction for voltage-mode and current-mode controlled regulators are identical. The results of the single-module regulator input filter interaction analysis are extended to the multi-module DPS case. Both line input filters and intermediate bus filters are designed for stability and to minimize interaction with the regulator modules. Implications of non-minimal dimensional subsystems are discussed. The eigenvalues due to parallel interaction are described, and it is shown how appropriate damping can be used to insure their stability. Straight-forward design guidelines are provided for the filters. Interaction of a non-ideal generator source with the DPS is described. This provides a useful application of the general subsystem interaction analysis. Stability is determined from different points in the system, and subsystem impedances are used to qualitatively describe the integrated system eigenvalue location. / Master of Science

This thesis deals with landscape architectural site-planning considerations of on-site alternative energy and material resources. On-site resources are those occurring on nearly every site. In, particular, the energies are solar, wind, water, and organic-waste; the materials are rock and earth. The thesis content includes basic information and guidelines necessary for making preliminary design decisions regarding these alternatives. Emphasis has been placed on analyzing site conditions, on measuring the available resource, on estimating the usable energy resource available, on storing the energy and on the use of the resource.In addition, there is a case study demonstrating the use of the information in the site-design process for a wind machine. The Appendix lists names and addresses of manufacturers concerned with alternative energy resources as well as containing examples of some of the literature for the wind energy industry. / Department of Landscape Architecture

The formulation of an accurate data base consisting of system state variable values is an initial and critical step in the economical and secure operation of modern power systems. The Least Median of Squares (LMS) estimator is ideal in the sense that it can provide a good state estimate despite high percentages of bad data and multiple bad leverage points. The estimator is, however, computationally intensive. In this thesis, an efficient algorithm is developed and implemented to increase the overall speed of the LMS estimator. The algorithm generates measurement samples in a manner that allows use of the resampling technique i.e., they make the system observable and also ensure that each measurement has a nearly equal probability of appearing in each of the measurement samples. / Master of Science

Interest in BiCMOS technology has been generated recently due to the potential advantages this technology offers over conventional CMOS which enjoys widespread use in today’s semiconductor industry. However, before BiCMOS can be readily adopted by the VLSI community, an understanding of the design issues and tradeoffs involved when utilizing it, must be achieved. The principal focus of this research is to move towards such an understanding through the means of analytical modeling and circuit simulation using PSPICE [1]. The device chosen for the modeling approach is the basic BiCMOS Inverting Buffer Driver. The model yields equations that characterize output rise and fall transients and quantify the delays incurred therein. At the end of the analysis, we have a composite set of delay equations that are a measure of the total gate delay and reflect the importance of individual device and circuit parameters in determining this delay. Further investigations conducted to determine the influence of device, circuit and process parameters on BiCMOS, indicate that this technology is far more resilient to variations in such parameters than CMOS. At the end of this research, we are able to make a definitive judgement about BiCMOS performance and its superiority over CMOS in the switching speed domain. / Master of Science

Proton coupled electron transfer reactions often involve tyrosine residues, because when oxidized, the phenolic side chain deprotonates. Tyrosine Z (YZ) is responsible for extracting electrons in a stepwise fashion from the oxygen evolving-complex in order to build enough potential to oxidize water. This process requires that each step YZ must deprotonate and reprotonate in order to maintain the high midpoint potential that is necessary to oxidize the oxygen-evolving complex, which makes YZ highly involved in proton coupled electron transfer reactions. In this thesis YZ has been studied within oxygen-evolving photosystem II utilizing electron paramagnetic resonance spectroscopy to monitor the tyrosyl radical that is formed upon light excitation. Kinetic analysis of YZ has shed light on the factors that are important for PSII to carry out water oxidation at the oxygen-evolving complex. Most notably the strong hydrogen-bonding network and the midpoint potential of YZ have been shown to be integral aspects of the water splitting reactions of PSII. By studying YZ within oxygen-evolving PSII, conclusions are readily applied to the native system.

Power conservation has become a high priority to South African industries due to recent environmental assessments and electricity price hikes. This research aims to demonstrate to Industry the many simple and cost effective ways to increase their industrial efficiency with simple modifications, as well as making them more aware of common assembly errors that significantly increase power consumption. This has been accomplished with the design, construction and testing of a test rig capable of producing the desired test results which simulate Industry usage. A test rig was required to test certain energy efficient equipment. This dissertation contains an explanation of the tests required, as well as how they were conducted. These test requirements directed the design outcomes of the test rig. Due to the variety of equipment to be tested, and the accuracy required, the test rig had to be fully adjustable. The design process is explained in this dissertation, along with relevant theory with regard to the testing procedures. The testing procedures were designed to be as accurate as possible. The setup equipment and procedure is briefly explained to ensure an understanding of the capabilities of the test rig. This dissertation contains the results obtained from testing a variety of couplings, belts and motors under different conditions. The results obtained show the difference between the efficiency of a standard motor and that of a high efficiency motor. The efficiency comparison of the Poly V TM, Poly Chain® and SPB V-belts showed very distinct advantages and disadvantages of each belt. The coupling testing was conducted under conditions of misalignment, and resulted in distinct differences in the efficiencies of each coupling at different degrees of misalignments. The couplings tested were the Fenaflex®, the Quick-Flex®, and the Fenagrid® coupling. All results obtained were analyzed and discussed in the relevant sections. The results obtained showed that the high efficiency motor is significantly more efficient than the standard motor at full load, although at low loading, the motor efficiencies were very similar. The coupling tests showed the negative effects misalignment has on the efficiency of the Quick-Flex® and Fenagrid® coupling as well as the capability of the Fenaflex® coupling to withstand the effects of large misalignments without significant efficiency loss. v The belt testing revealed the advantages and disadvantages of each type of belt used. This showed that although the synchronous belt did not lose efficiency with decreased tension, it became unstable, and was difficult to keep on the pulley if not aligned correctly. The V-belts can handle low tension well. Prolonged use of the belts can cause them to stretch, lowering the tension into a “danger zone” that will cause the belts to slip. This slip can damage the belt and pulley. At the lower tension of the V-belt, although the efficiency increases slightly, the vibration of the slack side of the belt is significant, and can be dangerous as the belt could jump off the pulley. The Poly V TM belt has some of the advantages of the V-belt, except that it is unable to maintain its friction at low tension, as the belt width prevents it from being wedged into the grooves like the V-belt. The fluid coupling tests showed that the shock loading on a high inertia system can be significantly reduced with the aid of a fluid coupling. The reduced shock loading can reduce energy consumption, and increase the life of electric motors and the equipment that they drive by preventing excessive overloading. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2011.