938 resultados para electricity distribution network


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The main objective of the Thesis is the description of the electricity distribution networks in Saint-Petersburg area and Stockholm as well. Main similarity and differences in the construction and technicalperformance are presented in the study. Present and future development and investment into the electricity distribution network of OJSC Lenenergo are viewed. The Thesis presents the overview of the power industry reform in Russia. The current state of the electricity distribution sector is described. The study views the participation of the foreign investor "Fortum Power and Heat Oy" inthe development and management of the OJSC Lenenergo. Benchmark comparison of the prices and tangible assets of the main electricity distribution companies in Saint-Petersburg and Stockholm areas is done.

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Electricity distribution network operation (NO) models are challenged as they are expected to continue to undergo changes during the coming decades in the fairly developed and regulated Nordic electricity market. Network asset managers are to adapt to competitive technoeconomical business models regarding the operation of increasingly intelligent distribution networks. Factors driving the changes for new business models within network operation include: increased investments in distributed automation (DA), regulative frameworks for annual profit limits and quality through outage cost, increasing end-customer demands, climatic changes and increasing use of data system tools, such as Distribution Management System (DMS). The doctoral thesis addresses the questions a) whether there exist conditions and qualifications for competitive markets within electricity distribution network operation and b) if so, identification of limitations and required business mechanisms. This doctoral thesis aims to provide an analytical business framework, primarily for electric utilities, for evaluation and development purposes of dedicated network operation models to meet future market dynamics within network operation. In the thesis, the generic build-up of a business model has been addressed through the use of the strategicbusiness hierarchy levels of mission, vision and strategy for definition of the strategic direction of the business followed by the planning, management and process execution levels of enterprisestrategy execution. Research questions within electricity distribution network operation are addressed at the specified hierarchy levels. The results of the research represent interdisciplinary findings in the areas of electrical engineering and production economics. The main scientific contributions include further development of the extended transaction cost economics (TCE) for government decisions within electricity networks and validation of the usability of the methodology for the electricity distribution industry. Moreover, DMS benefit evaluations in the thesis based on the outage cost calculations propose theoretical maximum benefits of DMS applications equalling roughly 25% of the annual outage costs and 10% of the respective operative costs in the case electric utility. Hence, the annual measurable theoretical benefits from the use of DMS applications are considerable. The theoretical results in the thesis are generally validated by surveys and questionnaires.

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Communications play a key role in modern smart grids. New functionalities that make the grids ‘smart’ require the communication network to function properly. Data transmission between intelligent electric devices (IEDs) in the rectifier and the customer-end inverters (CEIs) used for power conversion is also required in the smart grid concept of the low-voltage direct current (LVDC) distribution network. Smart grid applications, such as smart metering, demand side management (DSM), and grid protection applied with communications are all installed in the LVDC system. Thus, besides remote connection to the databases of the grid operators, a local communication network in the LVDC network is needed. One solution applied to implement the communication medium in power distribution grids is power line communication (PLC). There are power cables in the distribution grids, and hence, they may be applied as a communication channel for the distribution-level data. This doctoral thesis proposes an IP-based high-frequency (HF) band PLC data transmission concept for the LVDC network. A general method to implement the Ethernet-based PLC concept between the public distribution rectifier and the customerend inverters in the LVDC grid is introduced. Low-voltage cables are studied as the communication channel in the frequency band of 100 kHz–30 MHz. The communication channel characteristics and the noise in the channel are described. All individual components in the channel are presented in detail, and a channel model, comprising models for each channel component is developed and verified by measurements. The channel noise is also studied by measurements. Theoretical signalto- noise ratio (SNR) and channel capacity analyses and practical data transmission tests are carried out to evaluate the applicability of the PLC concept against the requirements set by the smart grid applications in the LVDC system. The main results concerning the applicability of the PLC concept and its limitations are presented, and suggestion for future research proposed.

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Deregulation of the electricity sector liberated the electricity sale and production for competitive forces while in the network business, electricity transmission and distribution, natural monopoly positions were recognised. Deregulation was accompanied by efficiencyoriented thinking on the whole electricity supply industry. For electricity distribution this meant a transition from a public service towards profit-driven business guided by economic regulation. Regulation is the primary means to enforce societal and other goals in the regulated monopoly sector. The design of economic regulation is concerned with two main attributes; end-customer price and quality of electricity distribution services. Regulation limits the costs of the regulated company but also defines the desired quality of monopoly services. The characteristics of the regulatory framework and the incentives it provides are therefore decisive for the electricity distribution sector. Regulation is not a static factor; changes in the regulatory practices cause discontinuity points, which in turn generate risks. A variety of social and environmental concerns together with technological advancements have emphasised the relevance of quality regulation, which is expected to lead to the large-scale replacement of overhead lines with underground cables. The electricity network construction activity is therefore currently witnessing revolutionary changes in its competitive landscape. In a business characterised by high statutory involvement and a high level of sunk costs, recognising and understanding the regulatory risks becomes a key success factor. As a response, electricity distribution companies have turned into outsourcing to attain efficiency and quality goals. This doctoral thesis addresses the impacts of regulatory risks on electricity network construction, which is a commonly outsourced activity in the electricity distribution network sector. The chosen research approach is characterised as an action analytical research on account of the fact that regulatory risks are greatly dependent on the individual nature of the regulatory regime applied in the electricity distribution sector. The main contribution of this doctoral thesis is to develop a concept for recognising and managing the business risks stemming from economic regulation. The degree of outsourcing in the sector is expected to increase in years to come. The results of the research provide new knowledge to manage the regulatory risks when outsourcing services.

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The electricity distribution sector will face significant changes in the future. Increasing reliability demands will call for major network investments. At the same time, electricity end-use is undergoing profound changes. The changes include future energy technologies and other advances in the field. New technologies such as microgeneration and electric vehicles will have different kinds of impacts on electricity distribution network loads. In addition, smart metering provides more accurate electricity consumption data and opportunities to develop sophisticated load modelling and forecasting approaches. Thus, there are both demands and opportunities to develop a new type of long-term forecasting methodology for electricity distribution. The work concentrates on the technical and economic perspectives of electricity distribution. The doctoral dissertation proposes a methodology to forecast electricity consumption in the distribution networks. The forecasting process consists of a spatial analysis, clustering, end-use modelling, scenarios and simulation methods, and the load forecasts are based on the application of automatic meter reading (AMR) data. The developed long-term forecasting process produces power-based load forecasts. By applying these results, it is possible to forecast the impacts of changes on electrical energy in the network, and further, on the distribution system operator’s revenue. These results are applicable to distribution network and business planning. This doctoral dissertation includes a case study, which tests the forecasting process in practice. For the case study, the most prominent future energy technologies are chosen, and their impacts on the electrical energy and power on the network are analysed. The most relevant topics related to changes in the operating environment, namely energy efficiency, microgeneration, electric vehicles, energy storages and demand response, are discussed in more detail. The study shows that changes in electricity end-use may have radical impacts both on electrical energy and power in the distribution networks and on the distribution revenue. These changes will probably pose challenges for distribution system operators. The study suggests solutions for the distribution system operators on how they can prepare for the changing conditions. It is concluded that a new type of load forecasting methodology is needed, because the previous methods are no longer able to produce adequate forecasts.

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In competitive electricity markets with deep concerns for the efficiency level, demand response programs gain considerable significance. As demand response levels have decreased after the introduction of competition in the power industry, new approaches are required to take full advantage of demand response opportunities. Grid operators and utilities are taking new initiatives, recognizing the value of demand response for grid reliability and for the enhancement of organized spot markets’ efficiency. This paper proposes a methodology for the selection of the consumers that participate in an event, which is the responsibility of the Portuguese transmission network operator. The proposed method is intended to be applied in the interruptibility service implemented in Portugal, in convergence with Spain, in the context of the Iberian electricity market. This method is based on the calculation of locational marginal prices (LMP) which are used to support the decision concerning the consumers to be schedule for participation. The proposed method has been computationally implemented and its application is illustrated in this paper using a 937 bus distribution network with more than 20,000 consumers.

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The use of distribution networks in the current scenario of high penetration of Distributed Generation (DG) is a problem of great importance. In the competitive environment of electricity markets and smart grids, Demand Response (DR) is also gaining notable impact with several benefits for the whole system. The work presented in this paper comprises a methodology able to define the cost allocation in distribution networks considering large integration of DG and DR resources. The proposed methodology is divided into three phases and it is based on an AC Optimal Power Flow (OPF) including the determination of topological distribution factors, and consequent application of the MW-mile method. The application of the proposed tariffs definition methodology is illustrated in a distribution network with 33 buses, 66 DG units, and 32 consumers with DR capacity.

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Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do Grau de Mestre em Energias Renováveis – Conversão Eléctrica e Utilização Sustentáveis

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Euroopan sähkösektori on ollut viimeisen vuosikymmenen suurten mullistusten kourissa. Sähkömarkkinoiden avautumisen jälkeen monopoliliiketoimintaa harjoittavien sähköyhtiöiden on ollut pakko parantaa tuottavuuttaan. Ratkaisuksi tähän on etsitty apua huolto- ja rakennustoimintojen ulkoistamisella. Ulkoistaminen on kuitenkin uusi menetelmä tällä sektorilla. Tämän tutkielman tavoitteena on selvittää syyt, jotka tanskalaisella sähköverkkoyhtiöllä oli huolto- ja rakennustoimintojen ulkoistamiseen, sekä löytää siitä saatavat hyödyt ja siihen sisältyvät riskit. Tutkimus suoritetaan käyttäen apuna kirjallisuutta, saatavilla olevia due diligence-, sekä muita raportteja ja analyysejä, sekä tapausta koskettavien tahojen haastatteluja.Lisäksi sähköverkkoalan asiantuntijoiden kanssa käytyjä konsultointia käytetäänselvitykseen. Tutkimus osoittaa, että perimmäiset ajurit huolto- ja rakennustoimintojen ulkoistamiseen tulivat lainmuutosten ja vapautuneiden sähkömarkkinoiden asettamista paineista. Kunnallisessa organisaatiossa parantaa tehokkuutta ulkoistamalla jotain toimintoja yksityisomisteiselle palvelun tuottajalle. Muut ulkoistamisesta odotetut hyödyt olivat alentuneet kustannukset, virtaviivaisempi organisaation ja sähköverkkoyhtiön tehottomista osista eroon pääseminen ennen sen myymistä.

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As a result of the recent regulatory amendments and other development trends in the electricity distribution business, the sector is currently witnessing radical restructuring that will eventually impact the business logics of the sector. This report represents upcoming changes in the electricity distribution industry and concentrates on the factors that are expected to be the most fundamental ones. Electricity network companies nowadays struggle with legislative and regulatory requirements that focus on both the operational efficiency and the reliability of electricity distribution networks. The forces that have an impact on the distribution network companies can be put into three main categories that define the transformation at a general level. Those are: (1) a requirement for a more functional marketplace for energy, (2) environmental aspects (combating climate change etc.), and (3) a strongly emphasized requirement for the security of energy supply. The first point arises from the legislators’ attempt to increase competition in electricity retail markets, the second one concerns both environmental protection and human safety issues, and the third one indicates societies’ reduced willingness to accept interruptions in electricity supply. In the future, regulation of electricity distribution business may lower the threshold for building more weather-resistant networks, which in turn means increased underground cabling. This development pattern is reinforced by tightening safety and environmental regulations that ultimately make the overhead lines expensive to build and maintain. The changes will require new approaches particularly in network planning, construction, and maintenance. The concept for planning, constructing, and maintaining cable networks is necessary because the interdependencies between network operations are strong, in other words, the nature of the operation requires a linkage to other operations.

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Strategic development of distribution networks plays a key role in the asset management in electricity distribution companies. Owing to the capital-intensive nature of the field and longspan operations of companies, the significance of a strategy is emphasised. A well-devised strategy combines awareness of challenges posed by the operating environment and the future targets of the distribution company. Economic regulation, ageing infrastructure, scarcity of resources and tightening supply requirements with challenges created by the climate change put a pressure on the strategy work. On the other hand, technology development related to network automation and underground cabling assists in answering these challenges. This dissertation aims at developing process knowledge and establishing a methodological framework by which key issues related to network development can be addressed. Moreover, the work develops tools by which the effects of changes in the operating environment on the distribution business can be analysed in the strategy work. To this end, the work discusses certain characteristics of the distribution business and describes the strategy process at a principle level. Further, the work defines the subtasks in the strategy process and presents the key elements in the strategy work and long-term network planning. The work delineates the factors having either a direct or indirect effect on strategic planning and development needs in the networks; in particular, outage costs constitute an important part of the economic regulation of the distribution business, reliability being thus a key driver in network planning. The dissertation describes the methodology and tools applied to cost and reliability analyses in the strategy work. The work focuses on determination of the techno-economic feasibility of different network development technologies; these feasibility surveys are linked to the economic regulation model of the distribution business, in particular from the viewpoint of reliability of electricity supply and allowed return. The work introduces the asset management system developed for research purposes and to support the strategy work, the calculation elements of the system and initial data used in the network analysis. The key elements of this asset management system are utilised in the dissertation. Finally, the study addresses the stages of strategic decision-making and compilation of investment strategies. Further, the work illustrates implementation of strategic planning in an actual distribution company environment.

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Existing electricity distribution system is under pressure because implementation of distributed generation changes the grid configuration and also because some customers demand for better distribution reliability. In a short term, traditional network planning does not offer techno-economical solutions for the challenges and therefore the idea of microgrids is introduced. Islanding capability of microgrids is expected to enable better reliability by reducing effects of faults. The aim of the thesis is to discuss challenges in integration of microgrids into distribution networks. Study discusses development of microgrid related smart grid features and gives estimation of the guideline of microgrid implementation. Thesis also scans microgrid pilots around the world and introduces the most relevant projects. Analysis reveals that the main focus of researched studies is on low voltage microgrids. This thesis extends the idea to medium voltage distribution system and introduces challenges related to medium voltage microgrid implementation. Differences of centralized and distributed microgrid models are analyzed and the centralized model is discovered to be easiest to implement into existing distribution system. Preplan of medium voltage microgrid pilot is also carried out in this thesis.

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The Finnish electricity distribution sector, rural areas in particular, is facing major challenges because of the economic regulation, tightening supply security requirements and the ageing network asset. Therefore, the target in the distribution network planning and asset management is to develop and renovate the networks to meet these challenges in compliance with the regulations in an economically feasible way. Concerning supply security, the new Finnish Electricity Market Act limits the maximum duration of electricity supply interruptions to six hours in urban areas and 36 hours in rural areas. This has a significant impact on distribution network planning, especially in rural areas where the distribution networks typically require extensive modifications and renovations to meet the supply security requirements. This doctoral thesis introduces a methodology to analyse electricity distribution system development. The methodology is based on and combines elements of reliability analysis, asset management and economic regulation. The analysis results can be applied, for instance, to evaluate the development of distribution reliability and to consider actions to meet the tightening regulatory requirements. Thus, the methodology produces information for strategic decision-making so that DSOs can respond to challenges arising in the electricity distribution sector. The key contributions of the thesis are a network renovation concept for rural areas, an analysis to assess supply security, and an evaluation of the effects of economic regulation on the strategic network planning. In addition, the thesis demonstrates how the reliability aspect affects the placement of automation devices and how the reserve power can be arranged in a rural area network.

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The Thesis is dedicated to development of an operative tool to support decision making of battery energy storages implementation in distribution networks. The basics of various battery technologies, their perspectives and challenges are represented in the Thesis. Mathematical equations that describe economic effect from battery energy storage installation are offered. The main factors that influence profitability of battery settings have been explored and mathematically defined. Mathematical model and principal trends of battery storage profitability under an impact of the major factors are determined. The meaning of annual net value was introduced to show the difference between savings and required costs. The model gives a clear vision for dependencies between annual net value and main factors. Proposals for optimal network and battery characteristics are suggested.

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Dynamic asset rating (DAR) is one of the number of techniques that could be used to facilitate low carbon electricity network operation. Previous work has looked at this technique from an asset perspective. This paper focuses, instead, from a network perspective by proposing a dynamic network rating (DNR) approach. The models available for use with DAR are discussed and compared using measured load and weather data from a trial network area within Milton Keynes in the central area of the U.K. This paper then uses the most appropriate model to investigate, through a network case study, the potential gains in dynamic rating compared to static rating for the different network assets - transformers, overhead lines, and cables. This will inform the network operator of the potential DNR gains on an 11-kV network with all assets present and highlight the limiting assets within each season.