This dissertation presents a comprehensive and integrated design methodology to optimize both the electrical and the economic performance of a utility power distribution system. The proposal is structured to facilitate its adoption and incorporation into the existing utility infrastructure by allowing the various portions of the new design to be implemented gradually into the existing infrastructure without the need to abandon the portions of the existing system that are performing satisfactorily. The topology of the substation plays a vital role in determining both the reliability and the economy of the distribution system. The ring bus topology is offered as the best topology design, and its characteristics as seen at the distribution level are examined. A key concept presented in this dissertation is that the distribution system must be optimized as a whole, not subsystem by subsystem. Optimizing the substation and the primary feeder system separately does not assure an optimal system; in fact, independent design of the two subsystems is likely to produce a non-optimal system laden with operational problems. An integrated approach is essential to assure optimum performance, and the integration process requires an iterative approach. This iterative approach is presented using an example. Innovative changes to the protection strategy of the feeder system can greatly enhance the reliability of the distribution system. The use of communication-based overcurrent detection is presented. This transmission-like scheme, when applied at the distribution level, improves both the reliability and the economy of the system substantially over traditional time-coordinated overcurrent protection philosophies. An application of these proposed innovations leads to the design of a hypothetical system, which is in turn analyzed from both electrical and economic perspectives.

This thesis deals with the issue of reconstruction 110/22kV distribution substation in economic point of view, where we will assess the benefits of a combination of their involvement using the discounted cost. It’s necessary to reconstruct distribution substation due to the increasing demand for electricity, upgrading equipment in the distribution systems, improve the reliability of electricity supply to customers, etc.. Distribution substation layout must meet conditions resulting from a law on energetics and operation of primary distribution networks.

Detta arbete har undersökt påverkan av en ökad solcellsinstallation på fördelningsstationen FS25 Änge med hjälp av historiska data och antaganden. Det har även undersökts hur ett batterilagringssystem skulle kunna hjälpa nätet vid den ökade mängden solcellsinstallationer. Arbetet har riktat sig mot den dagen då solproduktion förväntas vara som högst samtidigt som övrig tid på året beaktats. Den komponent som varit huvudfokus är transformatorerna i nätet. Tre scenarion har kollat på där solcellsimplementering skett i graderna 100%, 70% och 50% av alla kunder under respektive nätstation. Det visade sig att det största problemet är i fördelningsstationen som är dimensionerad utefter sammanlagring. När det kommer till solproduktion går det inte räkna med sammanlagring då den producerar som högst för alla anläggningar samtidigt. Därefter diskuteras de möjligheter som finns för att hjälpa FS25 Änge under överbelastning där BESS implementerades men även flexmarknaden kom upp som en möjlighet. Avslutningsvis diskuterades framtida arbete som skulle behöva göras på detta ämne, där det arbetet som är mest aktuellt är att se påverkan hos elsystemet om det installerades batterier hos alla kunder och inte bara de som ligger under en överbelastad transformator. / This work has examined the impact of increased PV-implementation on distribution station FS25 Änge using historical data and assumptions. It has also examined how a battery energy storage system could assist the grid with the increased amount of PV- installations. The focus of the work has been on the day when the solar production is expected to be at its highest while considering the rest of the year. The component that has been the focus is the power transformers in the grid. Three scenarios have been examined where solar cell implementation has occurred to the degrees of 100%, 70%, and 50% of all customers at each substation, respectively. It turned out that the biggest problem is in the distribution station, which is dimensioned based on aggregated storage. When it comes to solar production, aggregated storage cannot be considered as it produces at its highest for all consumers simultaneously. Furthermore, the possibilities to assist FS25 Änge during overload were discussed, where Battery Energy Storage Systems (BESS) were implemented, and the flexibility local market emerged as a potential solution. Finally, future work that needs to be done on this topic was discussed, with the most relevant being to examine the impact on the electrical system if batteries were installed for all customers, not just those under an overloaded power transformer.

Prescriptively, the requirement of fire safety protection systems for distribution substations is not provided in the compliance document for fire safety to the New Zealand Building Code. Therefore, the New Zealand Fire Service (NZFS) has proposed a list of fire safety protection requirements for distribution substations in a letter, dated 10th July 2002. A review by Nyman [1], has considered the fire safety requirements proposed by the NZFS and discussed the issues with a number of fire engineers over the last three years. Nyman concerned that one of the requirements regarding the four hour fire separation between the distribution substation and the interior spaces of the building may not be necessary when considering the risk exposure to the building occupants in different situations, such as the involvement of the sprinkler systems and the use of transformers with a lower fire hazard. Fire resistance rating (FRR) typically means the time duration for which passive fire protection system, such as fire barriers, fire walls and other fire rated building elements, can maintain its integrity, insulation and stability in a standard fire endurance test. Based on the literature review and discussions with industry experts, it is found that failure of the passive fire protection system in a real fire exposure could potentially occur earlier than the time indicated by the fire resistance rating derived from the standard test depending on the characteristics of the actual fire (heat release rate, fire load density and fire location) and the characteristics of the fire compartment (its geometric, ventilation conditions, opening definition, building services and equipment). Hence, it is known that a higher level of fire safety, such as 4 hour fire rated construction and use of sprinkler system, may significantly improve the fire risk to health of safety of occupants in the building; however, they could never eliminate the risk. This report presents a fire engineering Quantitative Risk Assessment (QRA) on a transformer fire initiating in a distribution substation inside a high-rise residential and commercial mixeduse building. It compares the fire safety protection requirements for distribution substations from the NZFS to other relevant documents worldwide: the regulatory standards in New Zealand, Australia and United States of America, as well as the non-regulatory guidelines from other stakeholders, such as electrical engineering organisation, insurance companies and electricity providers. This report also examines the characteristics of historical data for transformer fires in distribution substations both in New Zealand and United States of America buildings. Reliability of active fire safety protection systems, such as smoke detection systems and sprinkler systems is reviewed in this research. Based on the data analysis results, a fire risk estimate is determined using an Event Tree Analysis (ETA) for a total of 14 scenarios with different fire safety designs and transformer types for a distribution substation in a high-rise residential and commercial mixed-use building. In Scenario 1 to 10 scenarios, different combinations of fire safety systems are evaluated with the same type of transformer, Flammable liquid (mineral oil) insulated transformer. In Scenario 11 to Scenario 14, two particular fire safety designs are selected as a baseline for the analysis of transformer types. Two types of transformer with a low fire hazard are used to replace the flammable liquid (mineral oil) insulated transformer in a distribution substation. These are less flammable liquid (silicone oil) insulated transformers and dry type (dry air) transformers. The entire fire risk estimate is determined using the software package @Risk4.5. The results from the event tree analysis are used in the cost-benefit analysis. The cost-benefit ratios are measured based on the reduced fire risk exposures to the building occupants, with respect to the investment costs of the alternative cases, from its respective base case. The outcomes of the assessment show that the proposed four hour fire separation between the distribution substations and the interior spaces of the building, when no sprinkler systems are provided, is not considered to be the most cost-effective alternative to the life safety of occupants, where the cost-benefit ratio of this scenario is ranked fifth. The most cost-effective alternative is found to be the scenario with 30 minute fire separation and sprinkler system installed. In addition to the findings, replacing a flammable liquid insulated transformer with a less flammable liquid insulated transformer or a dry type transformer is generally considered to be economical alternatives. From the QRA analysis, it is concluded that 3 hour fire separation is considered to be appropriate for distribution substations, containing a flammable liquid insulated transformer and associated equipment, in non-sprinklered buildings. The fire ratings of the separation construction can be reduced to 30 minute FRR if sprinkler system is installed. This conclusion is also in agreement with the requirements of the National Fire Protection Association (NFPA).

This dissertation deals with the idea of annexing a new nuclear resource in the locality of the Dukovany Nuclear Power Plant and the way of its connection to the power system. The main aim of this dissertation is to design concrete solution of the connection of the new resource to a certain point of the power system and complete this design by means of chosen calculation. According to the task, this dissertation consists of three parts. The first part describes the current engineering solution of the main one line diagram of our two existing nuclear power plants and generally of chosen types of power plants abroad, too. There is also a design of the internal consumption of the nuclear power plants. The objective of the second part of this dissertation is to present the survey of the power and dispositional variants of the new resource in view and mainly assess general possibilities of its connection. Using all information from the preceding part, the third part presents the concrete design of the engineering solution of the connection of the new resource to the power system and also the calculation of parameters of block transmission line. Another dissertation named “Study of Slavětice Distribution Substation Enlargement for EDU New Resources“ concurs this part or more precisely, my dissertation as a whole . For my dissertation I have used some materials and information from the ČEZ Corporation which are confidential. I have also used some knowledge from the analysis from the EGÚ Brno Corporation. This dissertation neither represents nor substitutes a complex analysis of all aspects of a new nuclear resource in the Dukovany Nuclear Power Plant.

This master's thesis deals with the measurement of grounding systems in HV/LV distribution networks, which includes grounding system of distribution substation and transmission lines. Explores the issue and principles for the measurement of parameters, which are important for the protection of persons and animals in order not to touch exposed conductive part accidentally, protection of electrical machines and equipment against high fault current and dangerous surges while the correct function of the connected electrical equipment is maintained. These parameters include earth potential rise, ground resistance, soil resistivity, touch voltage, step voltage and transferred potential to the LV network. The aim of this work is the preparation, analysis and subsequent evaluation for the real measurement in practice. These earthing-system measurements were carried out at the distribution station and the concrete pole with a section disconnector. Then a numerical model of the grounding system of concrete pole was created in ANSYS. Subsequent evaluation of the results as numerical terms (comparison measurements and simulated results) and evaluation in terms of analytical (measurement results compliance with the standard) including the numerical model of the earthing system is solved in the practical part of the master's thesis.

This thesis focuses on the connectivity problems of the new sources to the electrical network. The first part of the thesis deals with the description of the new source and the method of its connection to the electrical network. Furthermore, in work, there are elaborated the blocking conditions for substation TR Neratovice expanded distribution point. A distribution network operator must receive an attachment application for connecting before the actual connection. The attachments consist of study cases of conjunction that values the inverse influence on the distributional network and informs the operator about the required measures for the reliable service with the new source. PSS Sincal computer software was used to survey the inverse influences on the distributional network. Based on processed data, the evaluation of conjunction of the synchronous generator to the grid at TR Neratovice substation was reconsidered.

This master’s thesis is concerned with the proposal of new locality electrification. There are 59 detached houses. The thesis is divided into theoretical part and computational part. In the theoretical part, there are all documents necessary for the successful proposal of the electrification. In the computational part is drafted distribution substation, high voltage power cable, proposal of low voltage power cables and protection. Each part is made for two versions (for the degree of electrification A and for the degree of electrification C) and recorded in cadastral maps. The proposal of distribution substation and high voltage power cable is made by traditional method - all calculations are processed by the designer. Low-voltage power cables and protection are implemented in a computer program Sichr (version 11.01) OEZ company.

[pt] Em geral, as subestações são projetadas com transformadores em paralelo, operando a meia carga, para assegurar continuidade no fornecimento de energia mesmo que um transformador do grupo falhe. Contudo, essa prática implica em custos elevados, especialmente no que diz respeito ao arranjo de subestações. Uma solução alternativa é a utilização de estoques compartilhados de transformadores reservas e unidades de subestações móveis, que devem atender a um grupo de subestações com as mesmas características elétricas. Neste contexto, esta tese propõe a utilização temporária de unidades de subestações móveis, que devem atuar para atender à demanda de energia enquanto o transformador reserva é instalado. Essa estratégia aumenta a confiabilidade do sistema e reduz os custos operacionais e de investimento para as concessionárias de energia. No entanto, o sucesso dessa abordagem está intrinsecamente ligado ao dimensionamento e localização adequada dos estoques. Para que bons resultados sejam alcançados, é preciso dimensionar os estoques de forma que não haja investimento desnecessário ou um número insuficiente de equipamentos, e considerar pontos estratégicos de armazenamento, de forma que o tempo de deslocamento dos equipamentos sobressalentes até o ponto de falha garanta a minimização dos custos associados. Posto isso, esta tese apresenta duas metodologias de otimização baseadas em simulação Monte Carlo e Algoritmo Genético: uma para dimensionar o número de transformadores reservas e unidades de subestações móveis por ano; e outra para posicionar de forma adequada tais equipamentos em subestações com capacidade de armazenamento. Ambos os métodos foram aplicados a um grupo de transformadores de duas concessionárias reais, visando demonstrar a capacidade da metodologia de encontrar um conjunto de soluções factíveis do ponto de vista técnico e econômico. / [en] In general, substations are designed with transformers in parallel, operating at half load, to ensure continuity of power supply even if a transformer in the group fails. However, this practice involves high costs, especially with regard to the arrangement of substations. An alternative solution is the use of shared stocks of reserve transformers and mobile substation units, which must serve a group of substations with the same electrical characteristics. In this context, this thesis proposes the temporary use of mobile substation units, which must act to meet the energy demand while the reserve transformer is installed. This strategy increases system reliability and reduces operational and investment costs for electric utilities. However, the success of this approach is intrinsically linked to the proper sizing and location of stocks. For good results to be achieved, it is necessary to size stocks so that there is no unnecessary investment or an insufficient number of equipment, and consider strategic storage points, so that the time taken to move the spare equipment to the point of failure minimizes the associated costs. Thus, this thesis presents two optimization methodologies based on Monte Carlo simulation and Genetic Algorithm: one to size the number of spare transformers and mobile substation units per year; and another to properly locate such equipment in substations with storage capacity. Both methods were applied to a group of transformers from two real utilities, aiming at proving the method s ability to find a set of feasible solutions from a technical and economic point of view.