Master of Science / Department of Electrical and Computer Engineering / Anil Pahwa / Due to the ongoing changes in the structure of the electricity markets, distribution networks have developed an appealing potential for housing distributed generation (DG). In order to make the most out of the present distribution network, this project report verifies the results and method developed in a paper (Optimal Allocation of Embedded Generation on Distribution Networks) by A. Kean and M. O’Malley, which discusses an efficient way of incorporating DG in the current power system. The methodology under consideration elaborates on how certain constraints should be adopted that will lead toward optimally sizing and placing DG in the network under examination. Along with that, the effect of voltage rise and short circuit current are observed which shows that a certain allocation to some buses will cause a sudden rise in voltage and short circuit levels throughout the network. Furthermore, the adopted methodology with its relative constraints is solved using linear programming. Linear programming provides a more accurate allocation than its heuristic counterparts when it comes to embedding DG in smaller networks. The adopted methodology is then applied to a section of the Irish rural distribution network and the results pinpoint that appropriate placement of the DG will pave the way toward higher levels of penetration. The results obtained showed the same pattern as those recorded in the aforementioned source paper, there were only minor differences that are the result of using different software’s than those that were used by the authors of the paper.

In global energy and industrial market, petroleum refining industry accounts for a major share. Through proper planning and the use of adequate mathematical models for the different processing units, many profit improving opportunities can be realized. The increasing crude oil price has also made refining of crude oil blends to be a common practice. This thesis aims to provide useful insight for planning of the integrated refinery subsystems. The main subsystems referred to are (1) The crude oil unloading subsystem (2) The production and product blending subsystem and (3) The product distribution subsystem. Aspen HYSYS® was first used to develop a rigorous model for crude distillation unit (CDU) and vacuum distillation unit (VDU). The rigorous model was validated with pilot plant data from literature. The information obtained from the rigorous model is further used to develop a model for planning of the CDU and VDU. This was combined with models (obtained from empirical correlations) for fluid catalytic cracker (FCC) and hydrotreater (HDT) units to form a mathematical programming planning model used for refinery production and product blending subsystem planning. Since two different types of crude were considered, the optimum volumetric mixing ratio, the sulphur content at that mixing ratio and the CDU flow rate were determined. The yields fraction obtained from the rigorous model were then used to generate regression model using least square method. The sulphur composition of the crude oil was used as independent variable in the regression model. The generated regression models were then used to replace the regular fixed yield approach in a refinery planning model and the results compared. From the results obtained, the proposed method provided an alternative and convenient means for estimating yields from CDU and VDU than the regular fixed yield approach. The proposed aggregate model for the production and products blending subsystem was integrated with the modified scheduling model for the crude unloading subsystem developed by Lee et al. (1996) and products distribution model developed by Alabi and Castro (2009) for refinery planning. It was found that the regression model could be integrated in a refinery planning model and that the CDU flow rate was maximised as compared to the non- integrated system.

This thesis investigates different issues related to the issuance of debt by sovereign bodies such as governments, under uncertainty about the future interest rates. Several dynamic models of interest rates are presented, along with extensive numerical experiments for calibration of models and comparison of performance on real financial market data. The main contribution of the thesis is the construction and demonstration of a stochastic optimisation model for debt issuance under interest rate uncertainty. When the uncertainty is modelled using a model from a certain class of single factor interest rate models, one can construct a scenario tree such that the number of scenarios grows linearly with time steps. An optimization model is constructed using such a one factor scenario tree. For a real government debt issuance remit, a multi-stage stochastic optimization is performed to choose the type and the amount of debt to be issued and the results are compared with the real issuance. The currently used simulation models by the government, which are in public domain, are also reviewed. Apparently, using an optimization model, such as the one proposed in this work, can lead to substantial savings in the servicing costs of the issued debt

Lic.-avh. (sammanfattning) Umeå : Sveriges lantbruksuniv. / Härtill 2 uppsatser.

This diploma thesis deals with optimization of process metallurgical material purchase and cutting with use of the problem solving of optimal material dividing, which is one of the linear programming problems. The aim of this problem solving is to minimize waste and to minimize the purchase costs for base material. The solution of this problem has the practical application at the company KULICKOVE SROUBY KURIM,a.s. This work is based on Deming Cycle (“Plan-Do-Check-Act”), as the basic method of solution efficiency and operations, processes and systems improvement.

Stochastické programování a optimalizace jsou velmi užitečné nástroje pro řešení široké škály inženýrských úloh zahrnujících neurčitost. Diplomová práce se zabývá stochastickým programováním a jeho aplikací při řešení logistických úloh. Teoretická část práce je věnována jak základním pojmům z teorie grafů, tak pojmům souvisejících s matematickým, lineárním, celočíselným a stochastickým programováním. Pozornost je věnována také návaznosti zmíněných pojmů na logistiku. Druhá část se zabývá tvorbou vlastních úloh prezentujících stochastické logistické modely, jejich implementací a výsledky.

Renewable power production is becoming a necessity to improve society and overcome the challenges of climate change. In Sweden, large-scale solar PV power is growing year-on-year and today comprises 1 percent of electricity production. Solar power, however, is an intermittent form of electricity production which, whilst being renewable, contributes to increasing grid instability. For the grid to stay in balance, at grid frequency 50 Hz, electricity must be consumed at the time of production. If there is a surplus of production or a sudden decrease in consumption, the frequency will deviate from the nominal value. When introducing larger quantities of intermittent power production, the power system inertia decreases, and the frequency becomes prone to deviate. To combat this, the Swedish TSO Svenska Kraftnät procures ancillary services which aid the grid when needed. For solar PV power to be able to contribute to these marketplaces, a battery storage solution system (BESS) is utilized. This thesis aimed to investigate the economic feasibility of co-locating a solar photovoltaic (PV) park with a battery energy storage system (BESS) and to determine the optimal size of the BESS. The study utilized a linear optimization model to simulate the operation of a 14 MW solar PV park with different sizes of BESS ranging from 1 MWh to 14 MWh. The analysis considered the revenue generated by providing different services to the electricity grid, such as energy arbitrage and frequency regulation. The results indicate that co-locating a solar PV park with a BESS increases revenue, and the optimal BESS size for a 14 MW solar PV park is between 1 and 8 MWh. Above this range, the revenue recedes due to the limitations of the grid connection, which restricts the BESS from participating in the ancillary service markets. The analysis considers the running costs associated with power discharge to the grid and initial BESS investment. The study did not account for ancillary market bids that are not accepted, which could have a significant impact on the revenue generated. The ongoing trend of lowering battery prices could further boost the economic assessment and increase interest in all battery sizes, resulting in larger battery system installations in general.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2006. / Härtill 4 uppsatser.

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