Browsing by Subject "Distribution system"

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Improving Distribution System Reliability Through Risk-base Doptimization of Fault Management and Improved Computer-based Fault Location
(2013-11-07) Dong, Yimai
Utilities of distribution systems now are under the pressure of improving the reliability of power supply, not only from the urge to increase revenue, but also from requirements of their customers and the Independent Service Organization (ISO)?s regulation on power quality. Optimization in fault management tasks has the potential of improving system reliability by reducing the duration and scale of outages caused by faults through fast fault isolation and service restoration. The research reported by this dissertation aims at improving distribution system reliability through optimized fault management. Three questions are explored and answered: 1) how to establish the cause-and-effect relationship between fault management and system reliability; 2) how can individual fault management tasks benefit from the newly emerged smart grid technologies; and 3) how to improve the overall performance of fault management under new operation condition. Optimization of the fault management is done through minimizing a risk function representing system reliability. The improvement in system reliability is approached in following steps: 1) a risk function consists of distribution reliability indices is defined as the criterion for system reliability; 2) a new fault location method is proposed first that can accurately locate the faults with the assistance of voltage-sag-measurements from system-wide Intelligent Electronics Devices (IEDs); 3) the fault management task of field inspection is optimized using the risk function and the probability model of the true fault location established using results from fault location; 4) the decision making on the execution of during-fault service restoration is optimized through Monte Carlo simulation; 5) the optimized fault management is utilized in processing the faults and the improvement in system reliability is assessed by reduction of costs associated with these faults. The proposed optimization is demonstrated on a realistic distribution system. The stochastic model of faults in the system is built with consideration of normal and extreme weather conditions. Results show that the proposed optimization is capable of improving system reliability by reducing the mean and variance of outage cost calculated over the simulated years.
Modeling and simulation of distribution system components in anticipation of a smarter electric power grid
(2011-05) Toliyat, Amir; Kwasinski, Alexis; Grady, Wiliam
Successful development of the electric power grid of the future, hereinafter referred to as a smart grid, implicitly demands the capability to model the behavior, performance, and cost of distribution-level smart grid components. The modeling and simulation of such individual components, together with their overall interaction, will provide a foundation for the design and configuration of a smart grid. It is the primary intent of this thesis, to provide a basic insight into the energy transfer of various distribution-level components by modeling and simulating their dynamic behavior. The principal operations of a smart grid must be considered, including variable renewable generation, energy storage, power electronic interfaces, variable load, and plug-in electric vehicles. The methodology involves deriving the mathematical equations of components, and, using the MATLAB/Simulink environment, creating modules for each component. Ultimately, these individual modules may be connected together via a voltage interface to perform various analyses, such as the treatment of harmonics, or to acquire an understanding of design parameters such as capacity, runtime, and optimal asset utilization.