This thesis derives the proper load shedding scheme for a distribution system with wind power generating units to maintain the power supply reliability for the islanding operation of micro grid systems after fault disturbance. The comparison of operation performance and control scheme between the fixed speed and the variable speed wind power generators are made. The seasonal wind power energy by the wind turbine is calculated by applying the exponential rate (Power Law) and Weibull possibility distribution model with the actual minutely wind speed data in Hengchun and Penghu area in 2005. The mean values of seasonal wind power output and standard deviation are determined for the design of load shedding scheme for the islanding operation of the distribution feeder. Moreover, a practical distribution feeder BX31 in Fengshan District in Taiwan Power Company (TPC) is selected for the computer simulation of micro grid systems. The systems voltage and power variation of the distribution feeder are investigated when the wind turbine is connected to the feeder by considering the weekday and weekend load models. The voltage sag on the distribution feeder and transient stability of wind turbine are simulated for the fault contingency with three-phase short-circuit fault occurred on the feeder outlet. Consequently, synchronous condensers are connected and the blade angle of wind turbines is then adjusted to improve the transient response of output characteristic of wind turbine. It is found that the power supply reliability of micro grid with wind power generations will be deteriorated following the tripping of wind turbines due to the oscillation of terminal voltage introduced by long fault clearing time. To solve the problem, the proper design of the tripping for the micro grid systems with wind turbines is derived according to the transient stability analysis. To restore the systems stability of the islanding systems, the proper amount of load shedding is determined and the switching of control modes of the wind turbine is executed, according to the power mismatch between wind turbine generation and load demand of the distribution feeder.

In this thesis, load scheduling problem for cogeneration plants is interpreted in the context of stochastic programming. Cogeneration (CHP) is an important technology in energy supply of many countries. Cogeneration plants are designed and operated to cover the requested time varying demands in heat and power. Load scheduling of cogeneration plants represents a multidimensional optimization problem, where heat and electricity demands, operational parameters and associated costs exhibit uncertain behavior. Cogeneration plants are characterized by their &lsquo / heat to power ratio&rsquo / . This ratio determines the operating conditions of the plant. However, this ratio may vary in order to adapt to the physical and economical changes in power and to the meteorological conditions. Employing reliable optimization models to enhance short term scheduling capabilities for cogeneration systems is an important research area. The optimal load plan is targeted by achieving maximum revenue for cogeneration plants. Revenue is defined for the purpose of the study as the sales revenues minus total cost associated with the plant operation. The optimization problem, which aims to maximize the revenue, is modeled by thermodynamic analyses. In this context, the study introduces two objective functions: energy based optimization, exergy-costing based optimization. A new method of stochastic programming is developed. This method combines dynamic programming and genetic algorithm techniques in order to improve computational efficiency. Probability density function estimation method is introduced to determine probability density functions of heat demand and electricity price for each time interval in the planning horizon. A neural network model is developed for this purpose to obtain the probabilistic data for effective representation of the random variables. In this study, thermal design optimization for cogeneration plants is also investigated with particular focus on the heat storage volume.

Finite Element Analysis on Planetary Three-Roll Rolling Advisor Prof.: Y. M. Hwang Student: F. H. Tsai ABSTRACT This paper used three-dimensional finite element code---Deform to analyze the plastic deformation behavior of material at the rolling-gap during planetary 3-roll rolling of rods or bars. The rigid-plastic model was used. The rolls are assumed to be rigid body and the change of temperature during rolling is ignored. The first part was used Deform to simulate the manufactured bars in factory. We analyzed the rolling force, torque and the shape after deformation. These results can offer knowledge for the design of actual rolling mill or pass schedule of the 3-roll rolling processes. The second part was compared with FEM and experiment. The simulation was made with the roll size and shape of a mini-type 3-roll rolling mill. We analyzed the rolling force, torque and the depth of spirals with different inclined angle, offset angle, roll shape and reduction.

The main goal of this thesis is to improve the efficiency of power consumption for single train and propose the effects of the voltage variation to AC/DC power flow. This thesis establishes a simplified mathematic model for motor drivers with the magnetic vector control laws. Furthermore, it designs the framework of the motor drives model with the power system blockset of the MATLAB/SIMULINK. The mass rapid transit(MRT) power system framework are also introduced in the thesis. Besides the power and propelment system model are developed. Due to the differences of the load pattern for the MRT system and the other customers, the analysis can be separated into static station load and dynamic load during the train operations. Static station load is constant and easy to measure. But dynamic load leads to some extent of variation depended on the MRT network characteristics and the headway of trains. The power consumption for dynamic load is about 60-70% of the whole MRT power consumption. The whole process of starting, acceleration, coasting and stopping are realistically concerned for the simulation of MRT operation. In this thesis, the DC system is composed of a 12 pulse rectifying transformer, a conductor rail, motor-driven induction drive control, VVVF inverter, and a 3-phase motor-driven induction electric power model. The performance for single train can be obtained very efficiently with the rate curves. To perform the MRT power system simulation, an AC/DC load flow analysis has been developed with Matlab. The power system model of an simulation for Taipei MRT system has been created, the AC/DC load flow analysis is executed to analyze the effects of traction substation, voltage fluctuation, and various load under the dynamic operation for multiple trains. The efficiency of proposed methodology to solve the optimal MRT operation is verified by comparing to the results of Train Performance Simulator (TPS), which has been used by Taipei MRT project. It is suggested that the proposed rigid modeling of propulsion driving system can enhance the accuracy of system simulation and provide the tool to achieve better planing of MRT operation.

With the rapid growth of load demand, the distribution system is becoming very complicated such that the operation efficiency and service quality are deteriorated during recent years. Engineers have to solve the problems by applying new technologies to enhance the efficiency of distribution system. In this thesis, an immune algorithm(IA) based on weighting selection as a decision maker is proposed to reach the desired switching operations such that transformer and feeder loading balance can be achieved. The IA antigen and antibody are equivalent to the objective and the feasible solution for a conventional optimization method. The concept of the information entropy is also introduced as a measure of diversity for the population to avoid falling into a local optimal solution. This algorithm prevents the possibility of stagnation in the iteration process and achieves the fast convergence for the global optimization. With the object-orient programming(OOP), this research project is to create the relationship of distribution element objects and encapsulation of data with all 22KV underground systems in Taichung district. The OOP does provide an effective tool for the management of distribution system database and the fault detection, isolation, and service restoration(FDIR) function of feeders and main transformers. According to the attributes of line switches, we can create the 22KV distribution system configuration with the topology processor. In order to calculate the current flows of line switches, this project will also execute the three phase load flow program with the customer information system(CIS), load survey, outage management information system(OMIS), and the data of all feeders and main transformers. In this thesis, the IA is used to solve the optimal switching problem by considering the customer load characteristics for the normal operation and the overload contingency of the distribution system. The efficiency of immune algorithm to solve the problem is verified by comparing to the computing time of the conventional binary integer programming for decision making of switching operation. A Taichung district distribution system is selected for computer simulation to demonstrate the effectiveness of the proposed methodology for solving the optimal switching operation of distribution system. The result of this thesis will be an important reference for distribution automation in Taiwan.

In this dissertation, the artificial intelligent Petri nets is applied to find the optimal switching operation for service restoration and feeder loading balance for 18-feeders distribution systems that containing the whole 24-hours load profiles of service zones. After the fault location has been identified and isolated for a system fault contingency, the Petri nets model with inference mechanism is derived and applied to solve the optimal load transfer among distribution feeders. For system normal operation condition, the load balancing among distribution feeders is obtained by the Petri nets model to enhance the operation efficiency of distribution systems. The switching operation, which will result in the loading balance among distribution feeders, is derived by the Petri nets model according to the loading cost of distribution systems. To determine the effectiveness of the proposed methodology, a Taipower (Taiwan Power Company) distribution system which serves a mixed types of customers is selected to perform the computer simulation. It is found that the Petri nets approach can enhance the solution process of fault restoration with proper load transfer and improve feeder load balance for distribution systems by considering the load characteristics of the service customers.

This objective of thesis is to derive the adaptive load shedding by artificial neural network (ANN) so that the amount of load shedding can be minimized. An actual industrial customer and Taipower system are selected for computer simulation to fit the ANN model. The mathematical models of generation, exciters, governors and loads are used in the simulator program. The back propagation neural method is considered for the neural network training of load shedding.To create the training data set for ANN models, the transient stability analysis is performed to fit the load shedding under different operation and fault condition. The back propagation method and L-M learning process are then used to fit the minimum load shedding without causing system stability problem. To verify the effectiveness of the proposed methodology for adaptive load shedding, three fault contingencies for both the industrial cogeneration system and Taipower system have been simulated. By compare to the conventional load shedding, it is found that the amount of load shedding can be minimized and adjusted according to the real time operation conditions of power systems.

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<p>Background</p><p>Strategic alliances have become increasingly popular within the business world, they can be seen as a way to improve the total output of the firm. Over the last 10 years, the industry endured trying times, the most notable being the events of September 11, 2001. That event drastically changed airline traveling all across the world. It also showed the importance of collaborations in order to stay competitive. Star Alliance began in 1997 and has since then grown into</p><p>the world’s largest airline alliance with a total market share of 25.1%.</p><p>Purpose</p><p>The raison d’être of this study is to quantify and analyze the augmentation of load factors over time, in terms of distribution, as they pertain to capacity performance of allied carriers within Star Alliance.</p><p>Method</p><p>In order to fulfill the purpose, a deductive approach to the research has been taken. Furthermore, due to the nature of the data, a quantitative approach has been used within. Two hypotheses will be stated and several research questions as well.</p><p>Result</p><p>It can be clearly seen that distribution of load factors has transformed during the years. There is a shift in both the skewness and the kurtosis of the distributions that can be seen when examining the frequency distribution charts. The kurtosis increases and the skew decreases, measures that are positive for the airlines, while the anomalies of 0% and 100% load factor have remained stable throughout the years. A general increase in the average load factors has also been seen.</p><p>Conclusion</p><p>By analyzing the empirical findings, it is clear that the load factor of the allied members has increased and that the proportion of the denied boardings decreased in relation to the average load factor. This means that the alternative hypothesis was accepted in the first hypothesis and that the second alternative hypothesis was accepted in the second hypothesis. The research also reveals a generally increased mean which together with the changes in the skew and kurtosis lead to an acceptance of the beta distribution. Furthermore, higher load factors were shown to have a strong correlation with the increase in efficiency and decrease in overselling.</p>

<p><p>Kitron had wishes to be able to test and measure how disturbance affects their vehicle electronic units before they have been verified by SP Technical Research Institute of Sweden in Borås. This work started with the writing of a demand specification together with Kitron for a product PSQS, Power Supply Quality Simulator, which can generate some test pulses according to a standard for electronic units to Volvos vehicles. A design proposal was developed with the help the demand specification and was verified with the help of simulations. All electric schematics was designed with the guide of the design proposal. The pulses realized in the works of this thesis are those which Kitron experienced that they have a need to test in their own premises and which are possible to generate with the means available. All work took place at Kitron in Jönköping, the restriction of the work has been the cost of components not to be to high as well as the finished product shall be easily managed. This thesis work resulted in a unit which is possible to produce a number of disturbances on the voltage feed to a unit under test. Some pulses have not been completely correct according to Volvos standard. There are large possibilities to further develop PSQS to a unit that follows Volvos standard and even other vehicle producer’s standards.</p></p>