Impact on the Distribution System due to Plug-In Electric Vehicles and Changes in Electricity Usage

Replacing conventional vehicles by Plug-in Electric Vehicles (PEVs) would likely increase electricity demand and put higher stress on the electrical power system. This thesis presents an approach to evaluate the impact on electrical distribution systems (DSs) caused by charging PEVs and load management of heating loads. The approach considers both vehicle usage statistics and demographic data to estimate when PEVs could be charged in different parts of a DS.A case study was performed on a residential and a commercial part of the DS in Gothenburg. Three different control strategies for the charging were investigated, i.e. uncontrolled, loss-optimal and price-optimal strategies. The control strategies would have a significant effect on the timing of the charging, as well as the access of available infrastructure for charging.The results showed that if all vehicles were PEVs and charged uncontrolled, peak demand would increase by between 21 - 35% in the residential area and by between 1-3% in the commercial area. If customers were directly exposed to the spot price at the Nordic day-ahead market and would charge according to the price-optimal control strategy, peak power would increase by 78% for the residential area and 14% for the commercial area. If the charging were controlled according to the loss-optimal control strategy, the charging would be conducted during off-peak hours without increasing peak demand, even if all vehicles were PEVs.By controlling the heating loads in the residential area according to the price-optimal control strategy peak demand would increase by more than 80%, while peak demand would be reduced by almost 10% if the loss-optimal control strategy were applied

Impact on the Distribution System due to Plug-In Electric Vehicles and Changes in Electricity Usage

Replacing conventional vehicles by Plug-in Electric Vehicles (PEVs) would likely increase electricity demand and put higher stress on the electrical power system. This thesis presents an approach to evaluate the impact on electrical distribution systems (DSs) caused by charging PEVs and load management of heating loads. The approach considers both vehicle usage statistics and demographic data to estimate when PEVs could be charged in different parts of a DS.A case study was performed on a residential and a commercial part of the DS in Gothenburg. Three different control strategies for the charging were investigated, i.e. uncontrolled, loss-optimal and price-optimal strategies. The control strategies would have a significant effect on the timing of the charging, as well as the access of available infrastructure for charging.The results showed that if all vehicles were PEVs and charged uncontrolled, peak demand would increase by between 21 - 35% in the residential area and by between 1-3% in the commercial area. If customers were directly exposed to the spot price at the Nordic day-ahead market and would charge according to the price-optimal control strategy, peak power would increase by 78% for the residential area and 14% for the commercial area. If the charging were controlled according to the loss-optimal control strategy, the charging would be conducted during off-peak hours without increasing peak demand, even if all vehicles were PEVs.By controlling the heating loads in the residential area according to the price-optimal control strategy peak demand would increase by more than 80%, while peak demand would be reduced by almost 10% if the loss-optimal control strategy were applied

Chalmers Campus as a Testbed for Intelligent Grids and Local Energy Systems

This paper presents an overview of a testbed for intelligent distribution grids, local energy systems, and energy flexible buildings, which is being developed at the campus of Chalmers University of Technology in Gothenburg, Sweden. It describes the test sites, the functionalities, and the planned demonstration activities within the scope of on-going research projects. The proposed demonstrations include a local energy market platform, energy management solutions for microgrids and smart buildings, as well as voltage control in distribution grids. The paper aims to show how the physical energy supply systems of the university are being adapted to integrate the communication and control set-ups that provide the technical requirements for smart grid interoperability. As an example, the on-site implementation of remote battery control is presented, where initial results show the feasibility and potential benefits of the external control. Finally, challenges and lessons learned during the development of the testbed are highlighted

An Overview of Modeling Approaches Applied to Aggregation-Based Fleet Management and Integration of Plug-in Electric Vehicles †

The design and implementation of management policies for plug-in electric vehicles (PEVs) need to be supported by a holistic understanding of the functional processes, their complex interactions, and their response to various changes. Models developed to represent different functional processes and systems are seen as useful tools to support the related studies for different stakeholders in a tangible way. This paper presents an overview of modeling approaches applied to support aggregation-based management and integration of PEVs from the perspective of fleet operators and grid operators, respectively. We start by explaining a structured modeling approach, i.e., a flexible combination of process models and system models, applied to different management and integration studies. A state-of-the-art overview of modeling approaches applied to represent several key processes, such as charging management, and key systems, such as the PEV fleet, is then presented, along with a detailed description of different approaches. Finally, we discuss several considerations that need to be well understood during the modeling process in order to assist modelers and model users in the appropriate decisions of using existing, or developing their own, solutions for further applications

Kotitalouksien energianhallinta aurinkosähköä ja sähköautoja hyödyntäen

With the increasing penetration of distributed renewable energy generation, time-of-use and real-time electricity pricing, as well as plug-in electric vehicles, applications for residential demand side management are becoming more appealing. In this work, we study the economical benefits of vehicle-to-grid and space heating load control for residential consumers with local photovoltaic generation. A linear programming model is constructed for cost-optimizing the energy management of multiple households with various electric vehicle and space heating system combinations, resulting in yearly electricity cost savings between EUR 120-290 (14-40%) per household. The benefits of increasing the number of co-operating households are found to saturate around 5 households, and we also highlight the importance of accounting for battery degradation costs in vehicle-to-grid optimization.Hajautettujen uusiutuvien energianlähteiden, sähkön yö- ja tuntihinnoittelun, sekä sähköautojen yleistymisen myötä kysyntäjouston sovellukset kotitaloustasolla ovat käyneet yhä houkuttelevammiksi. Tässä työssä tarkastellaan vehicle-to-grid-tekniikan ja lämmitysjouston taloudellista hyötyä aurinkosähkön pientuottajille, sekä muodostetaan lineaariseen optimointiin pohjautuva usean kotitalouden kustannusoptimaalinen energianhallintamalli. Saavutetut optimaaliset vuosittaiset kustannussäästöt yksittäisille kotitalouksille vaihtelevat noin 120 - 290 euron (14 - 40%) välillä, riippuen mallinnetuista sähköautoista ja lämmitysjärjestelmistä. Kotitalouksien määrän lisäämisen hyödyn havaitaan saavuttavan maksiminsa jo viiden kotitalouden kohdalla, ja tuloksista käy ilmi akkujen kulumisen kustannusten mallintamisen tärkeä rooli vehicle-to-grid-ohjauksen optimoinnissa

Smart operation of transformers for sustainable electric vehicles integration and model predictive control for energy monitoring and management

The energy transmission and distribution systems existing today are stillsignificantly dependent on transformers,despite beingmore efficient and sustainable than those of decadesago. However, a large numberof power transformers alongwith other infrastructures have been in service for decades and are considered to be in their final ageing stage. Anymalfunction in the transformerscouldaffect the reliability of the entire electric network and alsohave greateconomic impact on the system.Concernsregardingurban air pollution, climate change, and the dependence on unstable and expensive supplies of fossil fuels have lead policy makers and researchers to explore alternatives to conventional fossil-fuelled internal combustion engine vehicles. One such alternative is the introduction of electric vehicles. A broad implementation of such mean of transportation could signify a drastic reduction in greenhouse gases emissions and could consequently form a compelling argument for the global efforts of meeting the emission reduction targets. In this thesis the topic of a high penetration of electric vehicles and their possible integration in insular networksis discussed. Subsequently, smart grid solutions with enabling technologies such as energy management systems and smart meters promote the vision of smart households, which also allows for active demand side in the residential sector.However, shifting loads simultaneously to lower price periods is likely to put extra stress on distribution system assets such as distribution transformers. Especially, additional new types of loads/appliances such as electric vehicles can introduce even more uncertaintyon the operation of these assets, which is an issue that needs special attention. Additionally, in order to improve the energy consumption efficiencyin a household, home energy management systems are alsoaddressed. A considerable number ofmethodologies developed are tested in severalcasestudies in order to answer the risen questions.Os sistemas de transmissão e distribuição de energia existentes hoje em dia sãosignificativamente dependentes dos transformadores, pese embora sejammais eficientes e sustentáveis do que os das décadas passadas. No entanto, uma grande parte dos transformadores ao nível dadistribuição, juntamente com outras infraestruturassubjacentes, estão em serviço há décadas e encontram-se nafasefinal do ciclo devida. Qualquer defeito no funcionamento dos transformadorespode afetara fiabilidadede toda a redeelétrica, para além de terum grande impactoeconómico no sistema.Os efeitos nefastos associadosàpoluição do arem centro urbanos, asmudançasclimáticasea dependência de fontes de energiafósseis têm levado os decisores políticos e os investigadores aexplorar alternativas para os veículos convencionais de combustão interna. Uma alternativa é a introdução de veículos elétricos. Umaampla implementação de tal meio de transporte poderia significar uma redução drástica dos gases de efeito de estufa e poderiareforçar os esforços globais para ocumprimento das metas de redução de emissõesde poluentes na atmosfera.Nesta tese é abordado o tema da elevada penetração dos veículos elétricose a sua eventual integração numarede elétricainsular. Posteriormente, são abordadas soluções de redeselétricasinteligentes com tecnologias específicas, tais como sistemas de gestão de energia e contadores inteligentes que promovamo paradigmadas casas inteligentes, que também permitem a gestão da procura ativano sector residencial.No entanto, deslastrando significativamente as cargaspara beneficiar de preçosmais reduzidosé suscetíveldecolocarconstrangimentosadicionaissobre os sistemas de distribuição, especialmentesobre ostransformadores.Osnovos tipos de cargas tais como os veículos elétricospodem introduzir ainda mais incertezassobre a operação desses ativos, sendo uma questão que suscitaespecial importância. Além disso, com ointuitode melhorar a eficiência do consumo de energia numa habitação, a gestão inteligente daenergia é um assunto que também éabordadonesta tese. Uma pletora de metodologias é desenvolvida e testadaemvários casos de estudos, a fim de responder às questões anteriormente levantadas

Microgrid Energy Management

In IEEE Standards, a Microgrid is defined as a group of interconnected loads and distributed energy resources with clearly defined electrical boundaries, which acts as a single controllable entity with respect to the grid and can connect and disconnect from the grid to enable it to operate in both grid-connected or island modes. This Special Issue focuses on innovative strategies for the management of the Microgrids and, in response to the call for papers, six high-quality papers were accepted for publication. Consistent with the instructions in the call for papers and with the feedback received from the reviewers, four papers dealt with different types of supervisory energy management systems of Microgrids (i.e., adaptive neuro-fuzzy wavelet-based controls, cost-efficient power-sharing techniques, and two-level hierarchical energy management systems); the proposed energy management systems are of quite general purpose and aim to reduce energy usages and monetary costs. In the last two papers, the authors concentrate their research efforts on the management of specific cases, i.e., Microgrids with electric vehicle charging stations and for all-electric ships

On-Line Optimal Charging Coordination of Plug-In Electric Vehicles in Smart Grid Environment

This PhD research proposes a new objective function for optimal on-line PEV coordination. A new enhanced on-line coordinated charging using coordinated aggregated particle swarm particle optimization (OLCC-CAPSO) has been used to solve the PEV coordination objective objection and associated constraints. The objective function provides a chance for all PEVs to start charging as quickly as possible, while customer satisfaction function is being optimized subject to network criteria including voltage profiles, generator and distribution transformer ratings

Sustainable distribution network planning considering multi-energy systems and plug-in electric vehicles parking lots

Entre todos os recursos associados à evolução das redes elétricas para o conceito de smart grid, os sistemas de multi-energia e os veículos eléctricos do tipo plug-in (PEV) são dois dos principais tópicos de investigação hoje em dia. Embora estes recursos possam acarretar uma maior incerteza para o sistema de energia, as suas capacidades de demanda/armazenamento flexível de energia podem melhorar a operacionalidade do sistema como um todo. Quando o conceito de sistemas de multi-energia e os parques de estacionamento com estações de carregamento para os PEVs são combinados no sistema de distribuição, a demanda pode variar significativamente. Sendo a demanda de energia uma importante informação no processo de planeamento, é essencial estimar de precisa essa demanda. Deste modo, três níveis padrão de carga podem ser extraídos tendo em conta a substituição da procura entre carriers de energia, a demanda associada ao carregamento dos PEVs, e presença de parques de estacionamento com estações de carregamento no sistema. A presença de PEVs num sistema multi-energia obriga a outros requisitos (por exemplo, um sistema de alimentação) que devem ser fornecidos pelo sistema, incluindo as estações de carregamento. A componente elétrica dos PEVs dificulta a tarefa ao operador do sistema na tentativa de encontrar a melhor solução para fornecer os serviços necessários e utilizar o potencial dos PEVs num sistema multi-energia. Contudo, o comportamento sociotécnico dos utilizadores de PEVs torna difícil ao operador do sistema a potencial gestão das fontes de energia associada às baterias. Desta forma, este estudo visa providenciar uma solução para os novos problemas que irão ocorrer no planeamento do sistema. Nesta tese, vários aspetos da integração de PEVs num sistema multi-energia são estudados. Primeiro, um programa de resposta à demanda é proposto para o sistema multi-energia com tecnologias do lado da procura que possibilitem alternar entre fornecedores de serviços. Em seguida, é realizado um estudo abrangente sobre as questões relativas à modelação dos PEVs no sistema, incluindo a modelação das incertezas, as preferências dos proprietários dos veículos, o nível de carregamento dos PEV e a sua interação com a rede. Posteriormente é proposta a melhor estratégia para a participação no mercado de energia e reserva. A alocação na rede e os possíveis efeitos subjacentes são também estudados nesta tese, incluindo o modelo dos PEVs e dos parques de estacionamento com estações de carregamento nesse sistema de multi-energia.Among all resources introduced by the evolution of smart grid, multi-energy systems and plugin electric vehicles are the two main challenges in research topics. Although, these resources bring new levels of uncertainties to the system, their capabilities as flexible demand or stochastic generation can enhance the operability of system. When the concept of multienergy systems and plug-in electric vehicles (PEV) parking lots are merged in a distribution system, the demand estimation may vary significantly. As the main feed of planning process, it is critical to estimate the most accurate amount of required demand. Therefore, three stages of load pattern should be extracted taking into account the demand substitution between energy carriers, demand affected by home-charging PEVs, and parking lot presence in system. The presence of PEVs in a multi-energy system oblige other requirements (i.e. fueling system) that should be provided in the system, including charging stations. However, the electric base of PEVs adds to the responsibilities of the system operator to think about the best solution to provide the required services for PEVs and utilize their potentials in a multi-energy concept. However, the socio-technical behavior of PEV users makes it difficult for the system operator to be able to manage the potential sources of PEV batteries. As a result, this study tries to raise the solution to new problems that will occur for the system planners and operators by the future components of the system. In this thesis, various aspects of integrating PEVs in a multi-energy system is studied.Firstly, a carrier-based demand response program is proposed for the multi-energy system with the technologies on the demand side to switch between the carriers for providing their services. Then, a comprehensive study on the issues regarding the modeling of the PEVs in the system are conducted including modeling their uncertain traffic behavior, modeling the preferences of vehicle owners on the required charging, modeling the PEV parking lot behavior and its interactions with the network. After that the best strategy and framework for participating the PEVs energy in the energy and reserve market is proposed. The allocation of the parking lot in the network and the possible effects it will have on the network constraints is studied. Finally, the derived model of the PEVs and the parking lot is added to the multi-energy system model with multi-energy demand