Thesis (B.Eng.)--Memorial University of Newfoundland, 2005. / Bibliography: leaves 127-133.

This dissertation studies the performance of synchrophasor measurement obtained using substation Intelligent Electronic Devices (IEDs) and proposes new algorithms and test methodology to improve and verify their performance when used in power system applications. To improve the dynamic performance when exposed to sinusoidal waveform distortions, such as modulation, frequency drift, abrupt change in magnitude, etc, an adaptive approach for accurately estimating phasors while eliminating the effect of various transient disturbances on voltages and currents is proposed. The algorithm pre-analyzes the waveform spanning the window of observation to identify and localize the discontinuities which affect the accuracy of phasor computation. A quadratic polynomial signal model is used to improve the accuracy of phasor estimates during power oscillations. Extensive experimental results demonstrate the advantages. This algorithm can also be used as reference algorithm for testing the performance of the devices extracting synchronized phasor measurements. A novel approach for estimating the phasor parameters, namely frequency, magnitude and angle in real time based on a newly constructed recursive wavelet transform is developed. This algorithm is capable of estimating the phasor parameters in a quarter cycle of an input signal. It features fast response and achieves high accuracy over a wide range of frequency deviations. The signal sampling rate and data window size can be selected to meet desirable application requirements, such as fast response, high accuracy and low computational burden. In addition, an approach for eliminating a decaying DC component, which has significant impact on estimating phasors, is proposed using recursive wavelet transform. This dissertation develops test methodology and tools for evaluating the conformance to standard-define performance for synchrophasor measurements. An interleaving technique applied on output phasors can equivalently increase the reporting rate and can precisely depict the transient behavior of a synchrophasor unit under the step input. A reference phasor estimator is developed and implemented. Various types of Phasor Measurement Units (PMUs) and PMU-enabled IEDs (Intelligent Electronic Devices) and time synchronization options have been tested against the standards using the proposed algorithm. Test results demonstrate the effectiveness and advantages.

Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 253-261). Available also in a digital version from Dissertation Abstracts.

Thesis (Ph. D.)--Mississippi State University. Department of Electrical and Computer Engineering. / Title from title screen. Includes bibliographical references.

Thesis (M.Eng.)--Memorial University of Newfoundland, 2002. / Bibliography: leaves 116-119.

Thesis (Ph.D)--Electrical and Computer Engineering, Georgia Institute of Technology, 2010. / Committee Chair: Meliopoulos, A. P. Sakis; Committee Member: Deng, Shijie; Committee Member: Divan, Deepakraj; Committee Member: Harley, Ronald; Committee Member: Taylor, David. Part of the SMARTech Electronic Thesis and Dissertation Collection.

This thesis examines the response of air pollutant emissions, water use and carbon emissions from electric power supply systems (electrical grids) to market forces and natural and human disruptions. Specifically, the response of electrical grid operation decisions to emissions pricing and other factors, such as drought restrictions, is examined. The grid of the Electricity Reliability Council of Texas (ERCOT) is used as a source of data, and as a spatial and temporal test-bed. Price signals for NOx emissions have the potential to reduce NOx emissions from the ERCOT grid by up to 50%. In addition to lowering NOx, there are co-benefits to introducing NOx prices, including reductions in the emissions of SOx (24.9% to 70.9%), Hg (16.8% to 81.3%) and CO2 (8.7% to 21.1%). Water consumption was also decreased by 4.3% to 8.2%. The costs of redispatching electricity generation to reduce NOx emissions are, in many scenarios, comparable to conventional control costs. Higher CO2 prices produce many of the same changes in electricity generation as increases in NOx prices, but the simultaneous application of NOx and CO2 pricing produces complex effects. Under stress, such as drought induced water scarcity, dispatching decisions have the potential to increase water availability in regions in which drought is a concern. This dispatching had relatively small impacts on total water consumption summed over all regions of the ERCOT grid. However, the dispatching scenarios resulted in net increases in NOx, SOx, and CO2 emissions rates summed over all regions of the grid, particularly in regions that were absorbing the electricity generation that was exported out of the drought impacted regions. The costs of electricity dispatching, per volume of water consumption reduced in the drought impacted region, was generally greater than the cost of implementing dry cooling in the same facilities at high electricity demand levels, but comparable to dry cooling at low to moderate demand levels. Finally, while changes in total emissions can be used as a surrogate for air quality impacts, actual changes in air pollutant concentrations, such as ozone, exhibit complex spatial and temporal patterns in response to redispatching, including the creation of hot spots of elevated concentrations. / text

No description available.

Conventional power system stabilisers (PSS) are designed to eliminate poorly damped, low frequency power oscillations that occur between remote generating pools or power stations, due to different types and settings of the automatic voltage regulators at different power stations. The supplementary control of the PSS is exerted on the power system through a generator's excitation system to which the PSS is attached. In order to design these conventional power system stabilisers , requires accurate system data and an in-depth knowledge of classical control theory. This thesis investigates the use of an intelligent, non-linear PSS that utilises fuzzy logic techniques. Others have proposed the concept of such a PSS, since it does not require accurate system data. This thesis describes the basic aspects of power system stability . Thereafter the methods of modelling synchronous machines in a multi-machine power system are presented. The sample power system being studied and the simulation packages used in the investigations are introduced and the methods involved to design and tune a conventional power system stabiliser using classical control theory and design methods proposed by others, are discussed. The general concept of fuzzy logic is introduced and the application of fuzzy logic techniques to controller design is explained. Using the principles of fuzzy logic controller design, a fuzzy logic power system stabiliser utilising 9 rules is designed and tuned for the multi-machine power system under investigation. The fuzzy logic stabiliser is then applied to a synchronous motor in a pump storage scheme. Previous work has applied fuzzy logic stabilisers only to synchronous generators . To further compare the performance of the 9 rule fuzzy stabiliser, a 49 rule stabiliser developed by other researchers, and adapted to operate on the synchronous motor, is evaluated. Computer simulated results of each of the stabiliser's performances are presented. The results of the 9 rule fuzzy stabiliser are compared with the performance of a conventional linear stabiliser as well as with a 49 rule fuzzy stabiliser. The robustness properties of the fuzzy stabilisers are evaluated. The results further prove that with proper membership function selection, a simple fuzzy stabiliser that demands very little computational overheads can be achieved to provide adequate system damping. / Thesis (M.Sc. Eng.)-University of Natal, Durban, 2003.

This thesis investigates the design of damping controllers to alleviate the problem of low frequency electro-mechanical oscillations in power systems. The operating point and network parameters of power systems are continually changing, resulting in changes in system dynamics. The conventional controller design methodology has therefore come under increasing scrutiny for its lack of considerations for robustness. The thesis first outlines the conventional design of a power system stabilizer (PSS) and then applies two robust techniques (Hoo and Quantitative Feedback Theory, QFT) to the design problem. The single machine infinite bus (SMIB) model is used to illustrate the procedure for all three design techniques. The final design is undertaken to illustrate the more important problem of robust multi-machine PSS design using QFT. The design requires linearised models of the multi-machine system. A brief discussion is given on how these can be obtained. An introduction to decentralized control design in QFT is included to support the multi-machine design. Chapter three proceeds through the design steps required to generate a conventional PSS. The technique is shown to be simple for a given set of operating conditions. The controller is shown to be adequately robust over the given set of operating conditions albeit not by design. Chapter four introduces a design technique that directly addresses robustness issues during the controller design. For a restricted range of operating conditions the designed controller demonstrates the desired robustness and performance characteristics. The inherent difficulties with Hoo in PSS design become more apparent as the operating range is extended. Chapter five introduces the second robust controller design technique. QFT is shown to be more adept at dealing with increased operating ranges and changing specifications in the single-machine infinite-bus case. The controller is easy to generate and performs well over the entire range of operating conditions. QFT is also applied to the controller design for a four-machine study system. The design is a marginally more complex than in the single machine case but is still easily accomplished. This thesis confirms previous attempts at solving the design problem using the methods outlined above. The performance of all controllers is assessed for small and large disturbances using non-linear time domain simulations with models developed using PSCAD/EMTDC and MATLAB. / Thesis (M.Sc.)-University of Natal,Durban, 2002.