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Reliability and Availability Analysis of Mining Systems with Human-ErrorAlqudsi, Nadheer 18 July 2019 (has links)
This study presents reliability and availability analysis of mining systems with hardware and human-error failures. The failures of proposed models representing the mining systems could be safe or unsafe. To understand model reliability and availability behaviours, different values of failure and repair rates were used at different number of parallel units and different repair policies. Also, a model with partial and complete failures was analysed beside two miscellaneous models representing systems used in mining sector. The failure and repair rates are assumed constant. Markov method was used to perform analysis of the models and Laplace transforms were used to solve associated equations.
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Reliability assessment of electrical power systems using genetic algorithms / Reliability assessment of electric power systems using genetic algorithmsSamaan, Nader Amin Aziz 15 November 2004 (has links)
The first part of this dissertation presents an innovative method for the assessment of generation system reliability. In this method, genetic algorithm (GA) is used as a search tool to truncate the probability state space and to track the most probable failure states. GA stores system states, in which there is generation deficiency to supply system maximum load, in a state array. The given load pattern is then convoluted with the state array to obtain adequacy indices.
In the second part of the dissertation, a GA based method for state sampling of composite generation-transmission power systems is introduced. Binary encoded GA is used as a state sampling tool for the composite power system network states. A linearized optimization load flow model is used for evaluation of sampled states. The developed approach has been extended to evaluate adequacy indices of composite power systems while considering chronological load at buses. Hourly load is represented by cluster load vectors using the k-means clustering technique. Two different approaches have been developed which are GA parallel sampling and GA sampling for maximum cluster load vector with series state revaluation.
The developed GA based method is used for the assessment of annual frequency and duration indices of composite system. The conditional probability based method is used to calculate the contribution of sampled failure states to system failure frequency using different component transition rates. The developed GA based method is also used for evaluating reliability worth indices of composite power systems. The developed GA approach has been generalized to recognize multi-state components such as generation units with derated states. It also considers common mode failure for transmission lines.
Finally, a new method for composite system state evaluation using real numbers encoded GA is developed. The objective of GA is to minimize load curtailment for each sampled state. Minimization is based on the dc load flow model. System constraints are represented by fuzzy membership functions. The GA fitness function is a combination of these membership values. The proposed method has the advantage of allowing sophisticated load curtailment strategies, which lead to more realistic load point indices.
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