Electrical energy is one of the most common forms of energy these days. Consequently, electric power system is an indispensable part of any society. However, due to the deregulation of electricity markets and the growth in the share of power generation by uncontrollable renewable energies such as wind and solar, power system simulations are more challenging than earlier. Thus, new techniques for simplifying these simulations are needed. One important example of such simplification techniques is the power system reduction. Power system reduction can be used at least for four different purposes: a) Simplifying the power system simulations, b) Reducing the computational complexity, c) Compensating the data unavailability, and d) Reducing the existing uncertainty. Due to such reasons, power system reduction is an important and necessary subject, but a challenging task to do. Power system reduction is even more essential when system operators are facing very large-scale power systems and when the renewable energy resources like hydro, wind, and solar have a high share in power generation. This thesis focuses on the topic of large-scale power system reduction with high penetration of renewable energy resources and tries to pursue the following goals: • The thesis first reviews the different methods which can be used for simplifying the power system studies, including the power system reduction. A comparison among three important simplification techniques is also performed to reveal which simplification results in less error and more simulation time decrement. • Secondly, different steps and methods for power system reduction, including network aggregation and generation aggregation, are introduced, described and discussed. • Some improvements regarding the subject of power system reduction, i.e. on both network aggregation and generation aggregation, are developed. • Finally, power system reduction is applied to some power system problems and the results of these applications are evaluated. A general conclusion is that using power system simplification techniques and specially the system reduction can provides many important advantages in studying large-scale power systems with high share of renewable energy generations. In most of applications, not only the power system reduction highly reduces the complexity of the power system study under consideration, but it also results in small errors. Therefore, it can be used as an efficient method for dealing with current bulk power systems with huge amounts of renewable and distributed generations. / <p>The Doctoral Degrees issued upon completion of the programme are issued by Comillas Pontifical University, Delft University of Technology and KTH Royal Institute of Technology. The invested degrees are official in Spain, the Netherlands and Sweden, respectively. QC 20150116</p>

Operation of the electricity markets is subject to a number of strict and specific constraints such as continuous load-generation balance, security of supply, and generation technology related limitations. Contributions have been made to two important problems of the Electricity Markets, in the context of this study. In this study, Price Based Unit Commitment problem in the literature, which is a tool for the GENCO for operations planning, is extended considering the interdependencies between the Natural Gas (NG) and Electricity infrastructures and the uncertainty of Wind Power generation. The effect of the NG infrastructure physical limitations is considered via linearized NG transmission system equations, and the Wind energy sources and conventional generation resource uncertainties are simulated by Monte-Carlo simulations. The contribution of the forward energy Bilateral Contracts (BC), as a financial risk hedging tool is also included by modeling these in the proposed PBUC framework. In the case studies , it is observed that a GENCO could prevent its financial losses due to NG interruptions, by depositing only a portion of the midterm interrupted NG in the storage facilities. The Security Constrained Unit Commitment (SCUC) Problem is widely accepted tool in the industry which models the market clearing process. This study integrates two novelties to the SCUC problem / &bull / A discrete demand response model to consider active participation of the consumers, &bull / A hybrid deterministic/stochastic contingency model to represent the N-1 contingencies together with the uncertainties related with the wind power generation and system load. It is observed that the curtailment of available wind power capacity would enable the TSO to take corrective actions against occurrence of the contingencies and realization of the uncertainties in the most possible economical manner.

Power losses are always a cause of worry for any power grid. In India, the situation is even worse. Though recent reports by Ministry of Power shows that Aggregate Technical and Commercial losses (AT &C losses) have come down from 36.64% in 2002-03 to 27% in 2011-12, yet they are much higher than the losses seen in many of the developed nations. The reduction shown in power loss is because of the Electricity Act, 2003 and the amendments made to it in 2007 which controlled the commercial losses rather than the technical losses. According to Ministry of Power, technical losses (Transmission & Distribution losses or T&D losses) in India are reported to be 23.65% in 2011-12. However, according to the study done by EPRI, for systems deployed in developed countries, these losses are estimated to be in the range of 7-15.5%. T & D losses occur in four system components namely step-up transformers and high voltage transmission (0.5-1%), step down to in intermediate voltage, transmission and step down to sub transmission voltage level (1.5-3%), sub-transmission system and step down to low voltage for distribution (2-4.5%), and distribution lines (3-7%). 1% of power loss is approximately equivalent to annual loss of Rs 600 million for a single state. Hence, in a year, loss in distribution line alone causes approximate loss of Rs 1.8-4.2 billion per state. Understanding and reducing power losses in distribution lines which contribute nearly 50% of the total T&D losses assume significance and has formed the motivation for the work reported in the thesis. In recent years, the trend has been to encourage users to generate solar power predominantly at residential complexes and captive power plants at industrial complexes. It has been suggested in the literature that Distributed Generation (DG) can not only reduce the load demanded from the power grid but also the power loss. In this thesis, it has been shown that by the choice of proper size and location of DG, the power loss can be reduced substantially as compared to unplanned deployment of DGs. The objective of the thesis is to design strategy for location of distributed user generated power to maximize the reduction in power loss. The thesis begins with a study of distributed generation in primary distribution networks and proceeds to problem formulation, with the aim being to develop an algorithm that can find out the optimal locations for DG allocation in a network. A greedy approximation algorithm, named OPLODER (i.e. Optimal Locations for Distributed Energy Resources), is proposed for the same and its performance on a benchmark data set is observed, which is found to be satisfactory. The thesis then moves on to describe the actual data of 101,881 commercial, residential and industrial consumers of Bangalore metropolitan area. A loss model is discussed and is used to calculate the line losses in LV part of the grid and loss is estimated for the said actual data. The detailed analysis of the losses in the distribution network shows that in most cases the losses are correlated with the sanctioned load. However there are also some outliers indicating otherwise. The analysis concludes that the distributed generated sources need to be optimally located in order to benefit fully. Also presented thereafter is a study about the impact of electrical properties and the structure of the network on power loss. In the second part of the thesis, OPLODER was again used to process the BESCOM data of 101,881 consumers by modeling them to be connected in three topologies namely Bus (i.e. linear structure), Star (i.e. directly connected) and Hybrid (i.e. tree structure). In case of Bus topology, when DG capacity available is 5% of the demand in substation, OPLODER reduced the loss from 14.65% to 10.75%, from 11.63% to 7.71% and from 13.33% to 9.24% for IISc, Brindavan, and Gokula substations respectively. Similarly, for the same amount of DG in case of star topology, OPLODER reduced loss from 1.75% to 1.26%, from 3.39% to 2.59% and from 2.96% to 1.99% for IISc, Brindavan, and Gokula substations respectively. Thereafter, the available real world data is re-modeled as a tree-type structure which is closer to the real world distribution network and OPLODER is run on it. The results obtained are similar to those presented above and are highly encouraging. When applied to the three substations viz. IISc, Brindavan and Gokula, the power loss dips from 9.95% to 7.42%, from 6.01% to 4.44% and from 8.07% to 5.95%, in case of DG used is 5% of the demand in substation. For the optimal strategies worked out in the thesis, additional overheads will be present. These overheads are studied and it has been found that the present infrastructure and technologies will be sufficient to handle the smart distribution network and the optimal strategy for distributed sources.

This diploma work is dealing with problems related to production of electrical energy in compliance with environmental protection and assessment of its production from non-renewable sources in reference to sources being renewable. The work puts emphasis on the importance and utilization of solar electrical energy. The sun is a source that will not get dried or mined out and will not stop shining. The goal of diploma work was to appraise the investment effectiveness with regard to a photovoltaic power station and assess the power plant influence in relation to classic sources for energy production and environmental protection. Within the diploma work, there were appraised three variants of the investment project which assumed life time longer than 20 years comprising conventional financial flows, surface size of 30 000 m2 and roughly required output of 1.5 MW. Single options were assessed upon economical evaluation regarding different ways of financing, in terms of price, output and guarantees provided by suppliers including the assessment of grant influence on the project effectiveness. Based on these data, the most suitable version for the investment project of building up the photovoltaic power plant was chosen. At the conclusion, it is possible to state that the photovoltaic power plant is very considerate towards the living environment in contrast to classical sources for electrical energy production, for example coal-fired power plants which heavily contaminate the environment, and nuclear power plants with risks of radiation escapes.

The European policy focus on smart grids implies their development as an indispensable part of the future power system. However, the definition of a smart grid is broad and vague, and the actual implementation of a smart grid can differ significantly, depending on the stakeholders involved.This work aims to inform policy makers, the electricity industry and researchers about stakeholder interests and the technical complexities involved by presenting smart grids via a techno-institutional framework. This framework takes account of the technical nature of the electricity transport and supply service as well as the institutional nature of electricity markets, stakeholder perspectives and sector regulation. In addition, this work presents potential revenues resulting from flexibility management in smart grids and proposes a way forward for smart grids and flexibility management in Europe. / <p>QC 20170925</p>

The thesis focuses on theoretical and empirical analysis of oil and natural gas flows in Eurasia and maps Ukraine's transit position in the regional oil and gas supply chain. The aim of the thesis is to objectively evaluate possibilities of Eurasian energy integration by enlargement of the European energy market further to the East and to prospect Ukraine's involvement into a new geopolitical energy alliance, driven by EU. This dissertation builds up on economical, geographical, historical and political premises of markets integration as well as system approach of energy alliances development. It argues that (i) energy integration on contrary to traditional economic stream can be explained by system approach and geopolitical stream of energy expansionism; (ii) EU infrustructural oil and gas projects imply deeper integration of EU member-states with involed non-members and (iii) Ukraine's oil and gas transit status within Eurasian region facilitates its growing involvement into EU energy intiatives guided by the European rules. The thesis is organized into three chapters. The first one is predominately theoretical and seeks to summarize current theoretical approaches towards integration and trends of energy markets in Eurasia. The second chapter introduces the role of oil and gas transport capacities and Ukraine's transit status in resolving disparities of Eurasian energy supply chain. The third chapter describes condition of Ukrainian oil and gas infrastructure and tackles issues for reformation of national oil and gas transit pipelines. Securing access to energy supplies has been a driving factor of global development since the industrial revolution. Increasing demand for oil and gas has undermined energy and economic security of world centers. In Eurasia Europe and Asia has been competing for fossil fuels originating from Russia, Middle East and Central Asia. Since recently Eurasian energy security problem is being solved by development of new supply routes. These infrastructural projects are initiated by oil and gas consumers, suppliers and transitors competing over control in the infrastructure. Such competition destabilises Eurasian relations, leads to energy "wars", political conflicts and increases supplies disruption risks. To secure stability of energy supply chain producers, transitors and consumers of oil and gas resources should integrate, closely cooperate and jointly invest into improving the existing supply routes and efficiency of fuels consumtion, production and transportation. Oil and gas should be traded for technologies and capital securing control in the infrustucture of mutual interests. Development of further bilateral and multilateral tools of joint interest would also help in resolving energy related contradictions of the participating parties. The leading role in driving energy integration in Eurasia belongs to the EU being the most mature and advanced integration grouping in Eurasia. EU realises TEN-e projects and from recently a common foreign energy policy aimed to strengthen external cooperation with oil and gas suppliers and transitors, including Ukraine. Since 1970s Ukraine has been an important oil and gas transitor for Russian and Central Asian oil and gas to Europe. Ukrainian pipelines intermediate 10 % of oil and 50 % of gas imports of Europe. To counterbalance Russian energy diplomacy over Ukraine, EU is supporting Ukraine's efforts in such energy alliances as INOGATE or GUAM. Ukraine's recent accession to the South Eastern-European Energy Community should improve stability of gas and oil supplies to Europe and facilitate reformation of national transit capacities.

This diploma thesis addresses the current analytical procedures and policies of renewable energy production in the Czech Republic and, mainly deals with the policy modifications that occurred between 2010 to 2012 which also influenced this policy. To give more explanation to the entire picture of the energetic situation in the Czech Republic we have to analyze the current potential situation of renewable and non renewable resources, the quality of electrical distribution network, the framework of available energy resources in the Czech Republic, the costs of producing energy and its impact on the environment. The current global trend in most developed countries is the development of renewable energy sources but, this is not the current case in the Czech Republic which has in its plans to reach its target set by the European Union for the year 2020 . But, instead the Czech Republic would like to set a different goal and decrease the use of renewable energy resources and increase the use of nuclear energy. The support of the analysis policy for renewable energy sources in the Czech Republic is measured in comparison with the European Union, the United States of America and the Peoples Republic of China. The main goal is to evaluate this policies support for renewable energy sources in the Czech Republic and for its possible improvement.

This thesis deals with the issue of power flow analysis in a medium voltage (22kV) distribution network with a focus on the influence of distributed energy generation recources. At first the issue of operation of distributed energy resources and their reverse effects on the distribution system is presented in the thesis. Furtherly there are described their operational conditions from the legislation point of view. The part dealing with calculation compares two network configurations in terms of power quality and how the power quality is impacted by distributed energy resources. The attention is given to voltage conditions, short-circuit power, power conditions, losses and flicker. The first configuration corresponds to the real situation in the network, the other one is describing the changes after the new 110/22 kV substation implementation to the power supply area and the overal change of network configuration. The network model and run simulation is done using the E-Vlivy program.

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