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På uppdrag av Trafikverket har denna rapport syftet att ge en rekommendation baserat på jämförelse av nuvarande standarden IEC 60870-5-104 och den alternativa standarden IEC 61850. Studien jämför IEC 61850 och IEC 60870-5-104 och skillnader mellan dessa två standarder utifrån olika områden som kommunikation, säkerhet samt ekonomiska aspekter. I arbetets teoridel behandlas elnätet och hur elstationer i allmänhet fungerar utifrån kommunikationsprotokollen och hur systemen kommunicerar med andra enheter. Resultatet av arbetet visar att standarden IEC 61850 erbjuder stora möjligheter och fördelar i samtliga aspekter, och har även en utvecklingspotential. Med kommunikationsprotokollet IEC 61850 erhålls mer information i form av feltyp, direkta mätningar och styrning på kontrollanläggningar. Dock finns det en komplexitet i IEC 61850 som kan kräva större anpassningar för att ersätta tidigare protokoll på anläggningar vid byte. Utifrån säkerhetsaspekten uppvisar IEC 61850 styrka bland annat gällande skydd av integritet och konfidentialitet. Sammantaget visar arbetet att det finns stor fördel att använda sig av IEC 61850 vid framtida tillämpningar utifrån examensarbetets resultat On behalf of the Swedish Transport Administration (Trafikverket), this report aims to provide a recommendation based on a comparison of the current communication protocol standard IEC 60870-5-104 and the alternative standard IEC 61850. This study compares IEC 61850 and IEC 60870-5-104 and differences between these two standards based on different areas such as communication, security and economic aspects. In the theoretical part of this thesis, the electricity grid is treated and how electricity stations generally work based on the communication protocols and how the systems communicate with other devices. The result of the thesis shows that the standard IEC 61850 offers great opportunities and advantages in all aspects and has a potential for development. With the communication protocol IEC 61850, more information is obtained in form of error type, direct measurements and control at control plants. However, there is a complexity in IEC 61850 which may require major adaptations to replace previous protocols on plants when changes are needed. Based on the safety aspect, IEC 61850 shows strength among other things regarding protection of privacy and confidentiality. Overall, the work shows that there is a great advantage of applying IEC 61850 in future use based on this thesis results.

This chapter provided an overview of DSM and especially, DR. In the past years, a wide range of DR programs have been developed in different power systems across the world. These programs aim at engaging all the types of consumers: from large industrial customers to residential end-users with relatively small electricity consumption, considering also special types of consumers such as the EV and data centers. The primary motive for developing DR programs is that by enabling the participation of the demand side in electricity markets significant benefits are anticipated: more efficient and sustainable system planning, enhancement of the operation of the distribution system, lower and more stable electricity prices in the long run, mitigation of the market power of several participants and promotion of competition, economic benefits for the consumers, and increased operational flexibility. Increased operational flexibility is directly linked to accommodating the handicaps of the trend that indicates that significant amount of variable RES generation will be introduced in power systems in the future.

© The Institution of Engineering and Technology 2016. A decentralised control method that deals with current sharing issues in dc microgrids (MGs) is proposed in thisstudy. The proposed method is formulated in terms of 'modified global indicator' concept, which was originally proposedto improve reactive power sharing in ac MGs. In this work, the 'modified global indicator' concept is extended tocoordinate dc MGs, which aims to preserve the main features offered by decentralised control methods such as no need ofcommunication links, central controller or knowledge of the microgrid topology and parameters. This global indicator isinserted between current and voltage variables by adopting a virtual capacitor, which directly produces an output currentsharing performance that is less relied on mismatches of the multi-bus network. Meanwhile, a voltage stabiliser iscomplementary developed to maintain output voltage magnitude at steady state through a shunt virtual resistance. Theoperation under multiple dc-buses is also included in order to enhance the applicability of the proposed controller. Adetailed mathematical model including the effect of network mismatches is derived for analysis of the stability of theproposed controller. The feasibility and effectiveness of the proposed control strategy are validated by simulation andexperimental results.

Orientador: Vivaldo Fernando da Costa Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação Resumo: Quando um sistema interligado de corrente alternada sofre variações de carga, sua freqüência pode exibir um comportamento oscilatório. Se este mesmo sistema possuir um elo de corrente contínua em paralelo com as linhas de intercâmbio, esse efeito poderá ser atenuado devido à atuação do controlador de corrente do elo. Esta tese apresenta um estudo que avalia a eficiência de um elo de CC para o amortecimento de oscilações de freqüência de intercâmbio sob condições de pequenas perturbações, operando o sistema com Controle Automático de Geração (CAG). Um modelo de injeção de potência utilizado para representar o elo CC é implementado no Modelo de Sensibilidade de Potência (MSP). Uma das vantagens desse modelo é permitir o desacoplamento da rede em duas partes distintas: o balanço ativo e o balanço reativo, em que as duas podem ser tratadas juntas ou separadamente. Com a escolha desse modelo, tornou-se possível implementar toda a rede no formato de diagrama de blocos. Além disso, as barras de carga do sistema são acessíveis através do diagrama de blocos, o que torna possível variar também a característica da carga. Através dessa representação, tornou-se viável a inserção do elo de CC no diagrama de blocos, pois o mesmo foi modelado como uma injeção de potência nas barras terminais nos balanços ativo e reativo, fechando um novo balanço de potência. As análises no domínio do tempo foram realizadas no programa Matlab Simulink®. Também utilizando este software, um controlador de amortecimento de oscilações de potência (POD-Power Oscillation Damping Controller) foi projetado para a modulação da potência do elo de CC. Os resultados obtidos mostram que o elo de CC possui um grande potencial para a manutenção do amortecimento de oscilações de freqüência de modo inter-área, quando equipados com controladores POD. Abstract: When an interconnected alternate-current power system suffers variations of loads, its frequency can exhibit an oscillatory behavior. If this system possesses a direct-current link in parallel with the inter-tie lines, this effect could be decreased, due to the link current controller action. This work presents a study that evaluates the efficiency of DC link for the damping of interarea frequency oscillations under small disturbances, operating the system with automatic generation control (AGC). A DC power injection model is implemented in the Power Sensitivity Model (PSM). One of the advantages of this model is to allow the detach of the network in two distinct parts: the active and reactive balances, where the two can be dealt together or separately. With the choice of this model, it's possible to implement the complete network in the block diagram format. Moreover, the network load bus are accessible through the block diagram, which this are possible to vary the load characteristic. Through this representation, the insertion of DC link in the block diagram became viable, therefore it was modeled as a power injection in the terminals bus in the active and reactive balances, closing a new power balance. The time domain analysis is carried out the software Matlab Simulink®. Also using this software, a POD controller (Power Oscillation Damping Controller) was designed for the DC power modulation. The results show that DC link comprises a great potential for the maintenance of frequency oscillations damping in interarea mode, when coupled to POD controllers. Mestrado Energia Elétrica Mestre em Engenharia Elétrica