Made available in DSpace on 2014-12-02T11:16:55Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-02-06Bitstream added on 2014-12-02T11:20:53Z : No. of bitstreams: 1 000796421.pdf: 3105914 bytes, checksum: c80b88a795877d6f55a2267e9422db96 (MD5) / O conceito Smart Grid (SG) estabelece que, em adição ao fluxo de energia, a concessionária tenha um fluxo de dados de duas vias em todos os setores da rede até os consumidores. Através da Tecnologia da Informação e Comunicação (TIC), torna-se possível o sensoriamento de toda a grade de energia, a solução de falhas mais ágil e eficiente, e a teleproteção e gerenciamento dos ativos das concessionárias. Para que isso seja garantido, requisitos como segurança, confiabilidade e baixa latência são essenciais. Considerando que existem diversas aplicações SG, adaptar um sistema de comunicação, entre os medidores inteligentes (Smart Meters), para cada tipo de ambiente se torna complexo. Além disso, o estudo de comunicação do fluxo SG se torna oneroso na montagem de cenários reais, devido ao alto custo na aquisição de Smart Meters. A fim de possibilitar estudos simulados da comunicação SG de baixo custo, neste trabalho foi realizada a modelagem do protocolo IEEE 1815 DNP3, validou seu funcionamento através de modelagem das integrações IEEE 1815/ 802.15.4 e IEEE 1815/ 802.11b. A validação e análise foram realizadas pela modelagem e simulação de ambos os protocolos, em Very High Speed Integrated Circuit (VHSIC) Hardware Description Language (HDL), e efetuando medições de atraso na troca de mensagens DNP3 enviadas através dos protocolos sem fio integrados. Os requisitos de latência de teleproteção, em seu contexto geral, apontam a interface IEEE 802.15.4 como inadequada para esta aplicação por apresentar alta latência na presença de cenários de disputa de acesso, baixa vazão de dados e baixa resiliência de segurança implementada. Situação que não ocorre para a interface IEEE 802.11, que se torna factível pois apresenta latência, vazão de dados e robustez de segurança compatíveis com tal aplicação crítica / The Smart Grid (SG) concept provides that, in addition to the power flow, the utilities has a two-way data flow in all sectors of the grid to consumers. Through Information and Communication Technology (ICT), it becomes possible the sensing of entire power grid, the more efficient and faster solution failures, and the teleprotection and management of the assets of utilities. To ensure this, requirements such as security, reliability and low latency are essential. Considering that there are several applications SG, to adapt a communication system between Smart Meters for each type of environment becomes complex. Moreover, the communication study of data flow SG becomes expensive in assembling real scenarios, due to the high cost of acquisition of Smart Meters. To enable SG communication studies simulated in low cost, in this work was constituted the modeling of IEEE 1815 DNP3 protocol, validated its operation through modeling of IEEE 1815 / 802.15.4 and IEEE 1815 / 802.11b integrations. The validation and analysis were performed by modeling and simulation of both protocols in Very High Speed Integrated Circuit (VHSIC) Hardware Description Language (HDL), and performing measurements of delay in the exchange of DNP3 messages sent via integrated wireless protocols. The teleprotection latency requirements in its general context, indicate the IEEE 802.15.4 interface as inadequate for this application due to high latency scenarios in the presence of contention access, low data throughput and low resilience of improved security. Situation that does not occur for the IEEE 802.11 interface, which becomes feasible because it presents latency, data throughput and robustness safety critical application compatible with that SG

Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2016. / Power fluctuations in a microgrid are caused by disturbances due to the connection and disconnection of Distributed Generators (DG’s), as well as the irregular input of the sun and wind renewable energy. Renewable penetration such as the sun, wind and tidal energy causes intermittency which directly affects the input and resultant output power of a microgrid. Control systems have to be implemented on three different levels to ensure the stability and reliability of the power supplied to the load. This can be achieved by implementing the following: 1) Primary control with mechanical valves and actuators to translate feedback signals through droop control. 2) Secondary control with power electronics to facilitate maximum power point tracking, phase lock loops and switch mode inverters to manipulate the electrical signals to a desired set points including PID control. 3) Tertiary control with software program management to monitor the power flow as well as to evaluate congregated logic and implement decision making. Energy storage systems like super capacitors can compensate for power imbalance by providing excess stored energy to the microgrid for short periods of time. The added advantage of capacitor banks is that it can facilitate power factor correction where inductive loads like rotating motors form large part of the total load. Battery banks can compensate for energy shortage for longer periods of time. The duration of the compensation can be determined by the size, topology and the type of batteries used. The objectives of this study is to improve the unstable power output responses of a renewable energy microgrid by designing and analysing control strategies intended at power wavering compensation which also includes energy storage. Sub control systems is created and simulated in Matlab/Simulink for analytical comparative observations. Results of the simulated model are discussed and recommendations are given for future works.

Orientador: Ailton Akira Shinoda / Co-orientador: Valtemir Emerêncio do Nascimento / Banca: Alexandre Cesar Rodrigues da Silva / Banca: Leopoldo Rideki Yoshioka / Resumo: O conceito Smart Grid (SG) estabelece que, em adição ao fluxo de energia, a concessionária tenha um fluxo de dados de duas vias em todos os setores da rede até os consumidores. Através da Tecnologia da Informação e Comunicação (TIC), torna-se possível o sensoriamento de toda a grade de energia, a solução de falhas mais ágil e eficiente, e a teleproteção e gerenciamento dos ativos das concessionárias. Para que isso seja garantido, requisitos como segurança, confiabilidade e baixa latência são essenciais. Considerando que existem diversas aplicações SG, adaptar um sistema de comunicação, entre os medidores inteligentes (Smart Meters), para cada tipo de ambiente se torna complexo. Além disso, o estudo de comunicação do fluxo SG se torna oneroso na montagem de cenários reais, devido ao alto custo na aquisição de Smart Meters. A fim de possibilitar estudos simulados da comunicação SG de baixo custo, neste trabalho foi realizada a modelagem do protocolo IEEE 1815 DNP3, validou seu funcionamento através de modelagem das integrações IEEE 1815/ 802.15.4 e IEEE 1815/ 802.11b. A validação e análise foram realizadas pela modelagem e simulação de ambos os protocolos, em Very High Speed Integrated Circuit (VHSIC) Hardware Description Language (HDL), e efetuando medições de atraso na troca de mensagens DNP3 enviadas através dos protocolos sem fio integrados. Os requisitos de latência de teleproteção, em seu contexto geral, apontam a interface IEEE 802.15.4 como inadequada para esta aplicação por apresentar alta latência na presença de cenários de disputa de acesso, baixa vazão de dados e baixa resiliência de segurança implementada. Situação que não ocorre para a interface IEEE 802.11, que se torna factível pois apresenta latência, vazão de dados e robustez de segurança compatíveis com tal aplicação crítica / Abstract: The Smart Grid (SG) concept provides that, in addition to the power flow, the utilities has a two-way data flow in all sectors of the grid to consumers. Through Information and Communication Technology (ICT), it becomes possible the sensing of entire power grid, the more efficient and faster solution failures, and the teleprotection and management of the assets of utilities. To ensure this, requirements such as security, reliability and low latency are essential. Considering that there are several applications SG, to adapt a communication system between Smart Meters for each type of environment becomes complex. Moreover, the communication study of data flow SG becomes expensive in assembling real scenarios, due to the high cost of acquisition of Smart Meters. To enable SG communication studies simulated in low cost, in this work was constituted the modeling of IEEE 1815 DNP3 protocol, validated its operation through modeling of IEEE 1815 / 802.15.4 and IEEE 1815 / 802.11b integrations. The validation and analysis were performed by modeling and simulation of both protocols in Very High Speed Integrated Circuit (VHSIC) Hardware Description Language (HDL), and performing measurements of delay in the exchange of DNP3 messages sent via integrated wireless protocols. The teleprotection latency requirements in its general context, indicate the IEEE 802.15.4 interface as inadequate for this application due to high latency scenarios in the presence of contention access, low data throughput and low resilience of improved security. Situation that does not occur for the IEEE 802.11 interface, which becomes feasible because it presents latency, data throughput and robustness safety critical application compatible with that SG / Mestre

Orientador: André Nunes de Souza / Banca: Oscar Armando Moldonado Astorga / Banca: Paulo Sergio da Silva / Resumo: As smart grids e os smart meters, ou redes inteligentes, respectivamente, tornam-se uma realidade cada vez mais próxima dos consumidores residenciais mundo afora. Diversos paises vêm desenvolvendo estudos com foco nos impactos relacionados à introdução destas novas tecnologias, e a eficiência energética é um dos grandes objetivos a serem alcançados. Os ganhos relacionados à eficiência energética poderão ser percebidos diretamente pelo consumidor através da economia nas contas de energia elétrica. Também serão observados pelas concessionárias através da minimização das perdas de transmissão e distribuição, pelo aumento na estabilidade do sistema, na minimização do carregamento durante os horários de pico, entre outros. Para demonstrar o potencial de eficiência energética serão apresentadas duas referências, uma focando em medidores inteligentes e suas interfaces com os usuários, e a outra relacionando as smart grids a novos conceitos como o demand response. Os smart meters são a base para implantação das smart grids, além de serem indispensáveis na realização de testes como os apresentados. Existem no mercado diversos modelos de medidores eletrônicos disponíveis bem como kits didáticos para desenvolvimento, entretanto, dependendo da aplicação podem se tornar limitados ou inflexíveis quanto à modificações. Assim é apresentado o desenvolvimento de um smart meter de baixo custo com estrutura flexível, tendo com objetivo obter precisão e exatidão nas medidas além da capacidade de armazenar os dados coletados, possibilitando análises posteriores. O smart meter desenvolvido alcançou seus objetivos, mostrando-se uma ferramenta bastante interessante para o monitoramento da rede e também do comportamento dos consumidores / Abstract: The smart grids and smart meters become a reality closer to residential consumers worldwide. Several countries are developing studies with focus on impacts related to the introduction of these new technologies and energy efficiency is one of the major objectives to be achieved. Gains related to energy efficiency will be felt directly by the consumer through the economy in electricity bills. Will also be noted by the concessionaires by minimizing transmission and distribution losses, by the increased system stability, minimizing the load during peak hours, among others. To demonstrate the potential of energy efficiency will be presented two references, one focusing on the introduction of smart meters and their interfaces with users and other relating the smart grids and new concepts such as demand response. The smart meters are the basis for the implementation of the smart grids, and are indispensable to conducting tests as presented. There are many electronic meters as well as educational kits for development available in the market, however, depending on the application may become limited or inflexibe regarding to modifications. Finally it is presented the development of a low cost smart meter, with a flexibe structure, aiming to achieve accuracy and precision in the measurements plus the ability to store the collected data, allowing further analysis. The smart developed achieved it objectives and proved to be a very interesting tool to monitor the network and also the behavior of consumers / Mestre

In this thesis, we present several novel theoretical results in complex networks, most of which benefit from extensions of existing methods of analysis in electrical engineering. These results not only contribute to a better characterisation of the topology and structure of complex networks, but also provide a new way to study complex systems by modelling them as a flow network to determine how nodes nonlocally interact as a function of the adjacent physical laws. We also contribute towards a better understanding of how frequency synchronisation (FS) in coupled phase oscillator networks comes about by revealing the fundamental mechanisms and determinant conditions for nodes to become FS. Moreover, we design a scheme to control explosive synchronisation. Equipped with the theoretical knowledge obtained from the study of phase oscillator networks, we reveal the mechanism behind the onset of FS in realistic models of power grids and the causes behind frequency collapse. Furthermore, we put forward advanced control techniques and novel prediction methods to prevent blackouts from happening in those models. These results might help engineers to construct a stable, economic and efficient smart power grid in the near future. The breakthroughs in this thesis build up a bridge which, on the one hand, promotes the progress of the research in the fields of complex networks and synchronization by borrowing methods from electrical engineering and extending them to the treatment of complex networks, and on the other hand, aids engineers to efficiently solve some specific problems in smart grids based on the knowledge of approaches coming from the area of complex systems. Therefore, this thesis bridges the gap between engineering and physics by identifying, explaining and extending interdisciplinary approaches from these two disciplines to better understand models and networks considered within these fields.

A stable and reliable electrical power supply system is an inevitable pre-requisite for the technological and economic growth of any nation. Due to this, utilities must strive and ensure that the customer’s reliability requirements are met and that the regulators requirements are satisfied at the lowest possible cost. It is known fact around the world that 90% of the customer service interruptions are caused due to failure in distribution system. Therefore, it is worth considering reliability assessments as it provides an opportunity to incorporate the cost or losses incurred by the utilities customer as a result of power failure. This must be considered in the planning and operating practices. The system modelling and simulation study is carried out on one of the district’s distribution system which consists of 132 kV, 66 kV and 22 kV network in Aliwal North Sector ECOU. The reliability assessment is done on the 22, 66 and 132 kV system to assess the performance of the present system and also predictive reliability analysis for the future system considering load growth and system expansion. The alternative which gives low SAIDI, SAIFI and minimum breakeven costs is being assessed and considered. The reliability of 132 kV system could be further improved by constructing a new 132 kV line from a different source of supply and connecting with line coming from another district (reserve) at reasonable break even cost. The decision base could be further improved by having Aliwal North Sector context interruption cost. However, the historical data which may be used in Aliwal North Sector to acquire interruption costs from the customers are being proposed. The focus should be on improving the power quality on constrained networks first, then the reliability. Therefore for the Aliwal North power system network it is imperative that Eskom invest on the reliability of this network. This dissertation also analysed load reflected economic benefit versus performance expectations that should be optimized through achieving a balance between network performance (SAIDI) improvement, and total life cycle cost (to Eskom as well as the economy). Reliability analysis conducted in this dissertation used Aliwal North power system network as a case study; the results proved that the system is vulnerable to faults, planned and unplanned outages. Reliability evaluation studies were conducted on the system using DigSilent software in conjunction with FME. These two models gave accurate results with acceptable variance in most indices except for the ENS where the variance was quite significant. It can be concluded that DigSilent results are the most accurate results in all three reliability evaluation scenarios for the Aliwal North Power System, best interpretation being that of DigSilent.

Microgrid is an essential part of the nation’s smart grid deployment plan, recognized especially for improving efficiency, reliability, flexibility, and resiliency of the electricity system. Since microgrid consists of different distributed generation units, microgrid scheduling and real-time dispatch play a crucial role in maintaining economic, reliable, and resilient operation. The control and optimization performances of the existing online approaches degrade significantly in microgrid applications with missing forecast information, large state space, and multiple probabilistic events. This dissertation focuses on these challenges and proposes efficient online learning and optimization-based approaches. For addressing the missing forecast challenges on online microgrid operations, a new fitted rolling horizon control (fitted-RHC) approach is proposed in Chapter 2. The proposed fitted-RHC approach is designed with a regression algorithm that utilizes the empirical knowledge obtain from the day-ahead forecast to make microgrid real-time decisions whenever the intra-day forecast data is unavailable. Simulation results show that the proposed fitted-RHC approach can achieve the optimal policy for the deterministic case study and perform efficiently with the uncertain environment in the stochastic case study. / Includes bibliography. / Dissertation (PhD)--Florida Atlantic University, 2021. / FAU Electronic Theses and Dissertations Collection

Transformatorn är en viktig komponent i elnätet för att se till att det jämt och ständigt finns tillgång till elektricitet i samhället. ABB Power Grids i Ludvika, arbetar bland annat med att producera dessa transformatorer, som kan väga upp till flera hundra ton. Det krävs speciella vagnar som kan transportera de på järnvägen, ner till Norrköping hamn, för att sedan transporteras vidare ut till kund. Det krävs även att järnvägen är extra förstärkt ned till Norrköping, för att kunna transportera de allra tyngsta transformatorerna. Den här uppsatsen vill genom en kvalitativ forskningsmetodik undersöka varför ABB Power Grids hamnade i just Ludvika, hur viktiga tungtransporterna är för företagets överlevnad samt hur viktig ABB Power Grids verksamhet är för staden Ludvika. Detta undersöks delvis utifrån teorin om industrilokaliseringsfaktorer och multiplikatoreffekter. Metoden bygger på en kombination av litteraturstudier och semi-strukturerade intervjuer med tre nyckelpersoner, som arbetar eller har arbetet på ABB Power Grids. Resultatet tyder på att de olika lokaslieringsfaktorerna har varit mer eller mindre avgörande på ett indirekt sätt vid lokaliseringen. Transporterna är dock den lokaliseringsfaktor som fortsatt är av stor vikt för företaget och något de ständigt måste jobba aktivt med. Transporterna är avgörande för att företaget ska kunna finnas kvar i staden, vilket är viktigt då ABB Power Grids även indirekt genererar ca en femtedel av tätortens arbetstillfällen.

Electricity service providers (ESP) worldwide have increased their interest in the use of electrical distribution, transmission, generation, storage, and responsive load resources as integrated systems. Referred to commonly as "smart grid," their interest is driven by widespread goals to improve the operations, management and control of large-scale power systems. In this thesis I provide research into a novel agent-based simulation (ABS) approach for exploring smart grid system (SGS) dispatch, schedule forecasting and resource coordination. I model an electrical grid and its assets as an adaptive ABS, assigning an agent construct to every SGS resource including demand response, energy storage, and distributed generation assets. Importantly, real time is represented as an environment variable within the simulation, such that each resource is characterized temporally by multiple agents that reside in different times. The simulation contains at least as many agents per resource as there are time intervals being investigated. These agents may communicate with each other during the simulation, but only agents assigned to represent the same unique resource may exchange information between time periods. Thus, confined within each time interval, each resource agent may also interact with other resource agents. As with any agent-based model, the agents may also interact with the environment, in this case, containing forecasted environment, load and price information specific to each time interval. The resulting model is a time-independent global approach capable of: (1) capturing time-variant local grid conditions and distribution grid load balancing constraints; (2) capturing time-variant resource availability and price constraints, and finally, (3) simulating efficient unit-commitment real-time dispatches and schedule forecasts considering time-variant forecasted transactive market prices. This thesis details the need for such a system, discusses the form of the ABS, and analyzes the predictive behavior of the model through a critical lens by applying the resulting proof-of-concept simulation to a set of comprehensive validation scenarios. The resulting analysis demonstrates ABS as an effective tool for real-time dispatch and SGS schedule forecasting as applied to research, short-term economic operations planning and transactive systems alike. The model is shown to converge on economic opportunities regardless of the price or load-forecast shape and to correctly perform least-cost dispatch and schedule forecasting functionality.

A dissertation submitted to the Facaulty of Engineering and the Built Environment, University of the Witwatersrand in ful lment of the requirements of the degree of Master of science in Engineering September 2016 / Standalone microgrid studies are being done because an expansion of the existing utility grids to supply power to remote communities is not feasible. Standalone microgrids can be considered as one of the solutions for remote communities because power can be generated close to these communities and it minimizes cost related to power transmission. Renewable energy sources with large uctuations are frequently the source of power for these standalone microgrids. The uctuating nature of these renewable sources can often lead to frequent blackouts. This research is aimed at minimizing power uctuations using controllable energy storage systems. This MSc focuses on the analysis of the ramp rate and delay time requirements for controllable energy storage system used in standalone PV microgrids. Measured insolation data and recorded load demand data for typical domestic appliances are used in this study to analyze ramp rates present. The ramp rates are then used to determine the range of energy storage ramp rate and delay time required to maintain the microgrid voltage within the standardized range of 1pu 5%. From the recorded data it has been observed that PV power can be sampled from at least 1-second intervals without losing important information. The 1 second averaged ramp rates obtained from the insolation data measurements have been found to have the highest value of 0.12pu/sec. However, this ramp rate increases to 0.3pu/sec when the allowable microgrid voltage band is narrow (1pu 5%). These insolation ramp rates are very low compared to the ramp rates of typical loads that can be connected to a microgrid. This means that, if the energy storage system is speci ed to meet the load ramp rate requirements, it will be able to respond to the uctuating PV power. The results obtained from the simulations con rm that energy storage system ramp rate plays an important role in the stability of a standalone microgrid. The minimum allowable energy storage ramp rate was found to be 8.15pu/sec for load transients with a ramp time of 20ms. This value is 28 times the energy storage ramp rate required to cancel out insolation uctuations. This further con rms that energy storage system ramp rates must be speci ed using the load demand data. The maximum allowable delay time was also found to be 0.53s to maintain the microgrid voltage within the standardized range of 1pu 5%. This delay time is applicable when canceling out only the insolation uctuations. To cancel out load transient power uctuations, there should be no delay time. / MT2017