There are unique challenges and opportunities related to the integration of electric vehicles into the future power grid, especially the modern distribution grid since electric vehicle (EV) charging facilities and fast-charging stations are usually tied to low-voltage and medium-voltage power networks. The grid-connected EVs, if properly controlled, can operate as distributed energy storage and provide various ancillary services, such as peak shaving, fast-response reserve capacity, frequency regulation, voltage control and reactive supports. The purpose of this thesis is to integrate EVs to the power grid and provides suitable ancillary services to improve the grid reliability and stability. The larger future penetration of EVs and renewable energies is also taken into account to develop the vehicle-to-grid (V2G) control scheme with the constraints of EV charging and communication infrastructures. The main contents include: V2G mathematical model and system configuration; impact evaluation of EV integration and the V2G control framework; energy scheduling of EVs integration; V2G dynamic regulation services; control method of EV aggregator for dispatching a fleet of EVs; and the evaluation of V2G control scheme and hardware-in-the-loop experimental system design. 　　In the thesis, the impact of EV charging demand on the conventional distribution grid is firstly estimated to reveal the negative effects of the arbitrary EV charging and the necessity to control the EV charging process. The potential benefits EVs can bring into the power grid support are discussed and a V2G control framework is proposed to perform the V2G optimization and various regulation services. The current power electronics applied EV charging facilities and communication network are integrated into the V2G operation in the future distribution grid with microgrid and smaller installation of renewable generation units. 　　Next, mathematical model of V2G power control is formulated. Two optimization methods are proposed to schedule the EV charging and discharging energy to minimize the power losses and the operating cost while satisfying the mobility needs and the power system limitations. Subsequently, the dynamic regulation of V2G power is investigated to unleash the potential of EVs to provide multiple ancillary services simultaneously. In addition to V2G optimal energy scheduling, EVs can also be employed for dynamic power regulation which requires the fast response to the instantaneous imbalance between the power supply and demand. V2G power is controlled to mitigate the power fluctuation caused by the intermittent wind energy resources, and thus stabilize the system frequency and voltage. Finally, an EV-centric hybrid energy storage system is proposed, which combines the merits of V2G operation and superconducting magnetic energy storage (SMES) to enhance the power quality and system frequency stability. The critical issues in V2G applications are summarized in the end. / published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

In recent years, since the concept of smart grid rises and the existing power grids are continuously modernized, more and more electric vehicles (EVs) are integrated into the power grid. In the power grid, EVs are expected to provide various energy services, such as spinning reserves, regulation services, optimization services, stability improvement, reactive compensation and grid security. This thesis is to model, analyze and implement these energy services of EVs. 　　Firstly, a multilayer framework of a power system with vehicle-to-grid (V2G) and vehicle-to-vehicle (V2V) operation is proposed. Its fundamental components including batteries, renewable energy sources are modeled for system analysis. Moreover, a general model for multiply purposes is presented. 　　Secondly, based on the modeling of EVs and the power systems, the analysis on frequency regulation and transient stability of the V2G system can be carried out effectively. The objectives of the frequency regulation are to keep the system frequency constant, and eliminate the deviations fast and effectively. While, the transient stability is to observe the performances of the power systems integrated with EVs and superconducting magnetic energy storage (SMES) during emergency cases. The results illustrate that EVs are valuable for improve the frequency and transient stability of the power systems. 　　Finally, the coordination and optimization of the power systems with EVs are studied. Unit commitment involving EVs is analyzed, which uses EVs to replace some expensive generating units to achieve minimum operating cost and emissions. In addition, the optimal sizing of EV aggregations in the distribution power system is conducted to minimize the total power loss. And the individual EV in the aggregations is dispatched to achieve minimum charging cost by satisfying the optimal sized demand and the real-time pricing. The results verified that EVs can be used to achieve optimized goals, such as minimum costs, emissions and losses. / published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

Achieving a low carbon economy has been the focus of Hong Kong in recent years. Strategies are put forth to support sustainable energy, because Hong Kong has inadequate local and renewable energy reserves. Smart grid technologies have benefited many countries in the world, and countries such as the United States, the United Kingdom, China, and South Korea are exploring this new green energy strategy. Hong Kong’s power companies have considered smart grid technologies, conducting pilot projects to test their local feasibility. In this research, stakeholders’ perspectives of the current status of smart grids are overviewed in Hong Kong from the angle of policy aspect. Stakeholder theory is utilized as the framework for understanding and analyzing the perceptions of stakeholder groups. An integrated and modified stakeholder power-interest matrix was developed for analyzing level of power and interest of stakeholder groups on smart grid from policy dimension. Through the course of this research project, qualitative interviews were conducted for 11 interviewees with subjectsfrom1six stakeholder groups, including: academics, advisory bodies, business, government, non-governmental organizations, and power companies. Follow-up quantitative questionnaires were distributed to the same target group for stakeholder analysis and to map the level of power and interest of stakeholder groups regarding smart grid policy development in Hong Kong. The data collected from interviews were compared with and contrasted against each stakeholder groups and other countries, with a view to identifying common motivations, barriers, and policy suggestions. The findings reveal that the six stakeholder groups hold medium to high power and interest in smart grid policy development in Hong Kong. Common motivations identified by local stakeholder groups include: the right to choose their own energy mix for power generation, potential behavioural change via smart meter and tariff restructuring, possible energy savings and emissions reductions for the environment, and corporate social responsibility. The most significant motivation for smart grid development shared with other countries is the goal of achieving low carbon economy and energy efficiency. Shared barriers perceived by the six stakeholder groups are: unreliable renewable power supplies, significant capital investments required, impracticalities of supplying electricity back to the grid, transfers of additional power generation costs to consumers, and limited smart grid knowledge by the public. The most significant barrier shared with international countries is funding mechanism, yet it may be difficult for Hong Kong to secure funding from the government because of problems of trust. Three stages of recommendations are suggested. Short-term recommendations centre on the policy development direction of smart grid in Hong Kong, and include implementing dynamic pricing, undertaking a large-scale pilot program and establishing an awareness campaign (funded by the government)for educating the general public. Medium-term recommendation is to establish a joint green fund with the contributions of companies with large carbon footprints. Long-term recommendations include market liberalization and increases in market competition. / published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

Made available in DSpace on 2015-04-09T12:28:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-12-01Bitstream added on 2015-04-09T12:48:14Z : No. of bitstreams: 1 000813588.pdf: 5039777 bytes, checksum: 5cf7448ce5632b008c0f6ddc5804f4c6 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / 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 / 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

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.