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An analysis of new functionalities enabled by the second generation of smart meters in Sweden / Analys av nya funktioner möjliggjort av andra generationen smarta mätare i SverigeDrummond, Jose January 2021 (has links)
It is commonly agreed among energy experts that smart meters (SMs) are the key component that will facilitate the transition towards the smart grid. Fast-peace innovations in the smart metering infrastructure (AMI) are exposing countless benefits that network operators can obtain when they integrate SMs applications into their daily operations. Following the amendment in 2017, where the Swedish government dictated that all SMs should now include new features such as remote control, higher time resolution for the energy readings and a friendly interface for customers to access their own data; network operators in Sweden are currently replacing their SMs for a new model, also called the second generation of SMs. While the replacement of meters is in progress, many utilities like Hemab are trying to reveal which technical and financial benefits the new generation of SMs will bring to their operations. As a first step, this thesis presents the results of a series of interviews carried out with different network operators in Sweden. It is studied which functionalities have the potential to succeed in the near future, as well as those functionalities that are already being tested or fully implemeneted by some utilities in Sweden. Furthermore, this thesis analyses those obstacles and barriers that utilities encounter when trying to implement new applications using the new SMs. In a second stage, an alarm system for power interruptions and voltage-quality events (e.g., overvoltage and undervoltage) using VisionAir software and OMNIPOWER 3-phase meters is evaluated. The results from the evaluation are divided into three sections: a description of the settings and functionalities of the alarm, the outcomes from the test, and a final discussion of potential applications. This study has revealed that alarm functions, data analytics (including several methods such as load forecasting, customer segmentation and non-technical losses analysis), power quality monitoring, dynamic pricing, and load shedding have the biggest potential to succeed in Sweden in the coming years. Furthermore, it can be stated that the lack of time, prioritization of other projects in the grid and the integration of those new applications into the current system seem to be the main barrier for Swedish utilities nowadays. Regarding the alarm system, it was found that the real benefits for network operators arrive when the information coming from an alarm system is combined with a topology interface of the network and a customer notifications server. Both applications could improve customer satisfaction by significantly reducing outage time and providing customers with real-time and precise information about the problems in the grid.
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ANALYSIS AND MITIGATION OF FREQUENCY DISTURBANCES IN AN ISLANDED MICROGRIDMondal, Abrez 03 August 2017 (has links)
No description available.
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Study of FACTS/ESS Applications in Bulk Power SystemZhang, Li 27 November 2006 (has links)
The electric power supply industry has evolved into one of the largest industries. Even though secure and reliable operation of the electric power system is fundamental to economy, social security and quality of modern life, the complicated power grid is now facing severe challenges to meet the high-level secure and reliable operation requirements.
New technologies will play a major role in helping today's electric power industry to meet the above challenges. This dissertation has focused on some key technologies among them, including the emerging technologies of energy storage, controlled power electronics and wide area measurement technologies. Those technologies offer an opportunity to develop the appropriate objectives for power system control.
The use of power electronics based devices with energy storage system integrated into them, such as FACTS/ESS, can provide valuable added benefits to improve stability, power quality, and reliability of power systems. The study in this dissertation has provided several guidelines for the implementation of FACTS/ESS in bulk power systems.
The interest of this study lies in a wide range of FACTS/ESS technology applications in bulk power system to solve some special problems that were not solved well without the application of FACTS/ESS. The special problems we select to solve by using FACTS/ESS technology in this study include power quality problem solution by active power compensation, electrical arc furnace (EAF) induced problems solution, inter-area mode low frequency oscillation suppression, coordination of under frequency load shedding (UFLS) and under frequency governor control (UFGC), wide area voltage control.
From this study, the author of this dissertation reveals the unique role that FACTS/ESS technology can play in the bulk power system stability control and power quality enhancement in power system. In this dissertation, almost all the studies are based on the real system problems, which means that the study results are special valuable to certain utilities that have those problems. The study in this dissertation can assist power industry choose the right FACTS/ESS technology for their intended functions, which will improve the survivability, minimize blackouts, and reduce interruption costs through the use of energy storage systems. / Ph. D.
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An Adaptive Underfreuqency Load-Shedding Scheme Considering Distributed Generation and Area Balance / Balanserad och adaptiv belastningsfrånkoppling i multi-area kraftsystem med hög andel distribuerad kraftproduktionHsiao, Yu-Chieh January 2024 (has links)
In the past decades, the renewable penetration in power systems has steadily increased, and is also expected to grow exponentially in the following years. Encountering this fast growing trend, the underfrequency load-shedding schemes, as the last resort of power systems in terms of frequency stability, have been implemented in a decentralized way where the settings are predefined and fixed. The purpose of the underfrequency load-shedding scheme is to disconnect a certain amount of loads to reduce load-generation imbalance following generator outages, while the renewable energy sources, implemented as distributed generation units can result in the situations where substantial amount of distributed generation can be disconnected together with loads at the same time. This can to some extent cancel out the effect of shedding loads, and in some extreme cases, aggravate frequency response. Apart from the impact of distributed generation, in some power systems there can be several areas where large amount of power is always exchanged in between. Inappropriate load-shedding amount and location can increase the risks of tie-line overloading, further resulting in tripping of tie-lines. In order to tackle these problems, an adaptive underfrequency load-shedding scheme was proposed which utilizes distributed feeder power measurements, measurements from distributed generation, as well as the SCADA system that serves as the main role of monitoring and control. The implementation of the proposed architecture is also explained in the thesis. The results exhibit that the proposed scheme is able to alleviate the stress of tie-line power flow to some extent following power outages, while also be affected by generation loss size and location. Besides, the proposed scheme also provides contribution to frequency stabilization by shedding less distributed generation. / Under de senaste decennierna har andelen förnybar produktion i elkraftsystem globalt ökat markant ökat och förväntas också fortsätta växa avsevärt under de kommande åren. Samtidigt med denna utveckling är det viktigt att beakta de systemvärn som består av belastningsfrånkoppling för frekvensåterställning som implementerats med fördefinierade inställningar på ett decentraliserat vis. Avsikten med ett sådant system värn är att koppla bort en viss mängd last för att undvika att frekvensen sjunker under tillåtna gränsvärden i samband med ett större fel, t.ex. att en större generator kopplas bort. Eftersom den förnybara produktionen ofta är distribuerad i nätet, kan en sådan från koppling av last dock medföra att stora mängder förnybar produktion kopplas bort samtidigt. Detta kan i vissa fall tänkas innebära att lastfrånkopplingen innebär en försämrings av frekvensen. Utöver effekterna på distribuerad produktion som ett systemvärn för lastbortkoppling kan ha, så kan det även innebära försämringar i kraftsystem bestående av flera områden, s.k. multiarea kraftsystem där enstaka förbindelser utgör flaskhalsar för överföringen. En olämpligt vald bortkoppling av last kan leda till överbelastning av de ledningar som går mellan områdena i kraftsystemet. I syfte att hantera bägge dessa problem föreslås i detta arbete en adaptiv lastfrånkopplingsmekanism som använder mätningar i distributionsnätet via SCADA systemet, vilket utgör basen i lösningen. Föreliggande rapport presenterar lösningen i detalj, resultaten visar att lösningen kan minska belastningen på förbindelserna mellan områden i ett kraftsystem för vissa fall. Dessutom bidrar den föreslagna lösningen till ett bättre bidrag till frekvensstabiliteten genom att en lägre mängd distribuerad förnybar kraft kopplas bort.
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A Wide-Area Perspective on Power System Operation and DynamicsGardner, Robert Matthew 23 April 2008 (has links)
Classically, wide-area synchronized power system monitoring has been an expensive task requiring significant investment in utility communications infrastructures for the service of relatively few costly sensors. The purpose of this research is to demonstrate the viability of power system monitoring from very low voltage levels (120 V). Challenging the accepted norms in power system monitoring, the document will present the use of inexpensive GPS time synchronized sensors in mass numbers at the distribution level. In the past, such low level monitoring has been overlooked due to a perceived imbalance between the required investment and the usefulness of the resulting deluge of information. However, distribution level monitoring offers several advantages over bulk transmission system monitoring. First, practically everyone with access to electricity also has a measurement port into the electric power system. Second, internet access and GPS availability have become pedestrian commodities providing a communications and synchronization infrastructure for the transmission of low-voltage measurements. Third, these ubiquitous measurement points exist in an interconnected fashion irrespective of utility boundaries. This work offers insight into which parameters are meaningful to monitor at the distribution level and provides applications that add unprecedented value to the data extracted from this level. System models comprising the entire Eastern Interconnection are exploited in conjunction with a bounty of distribution level measurement data for the development of wide-area disturbance detection, classification, analysis, and location routines.
The main contributions of this work are fivefold: the introduction of a novel power system disturbance detection algorithm; the development of a power system oscillation damping analysis methodology; the development of several parametric and non-parametric power system disturbance location methods, new methods of power system phenomena visualization, and the proposal and mapping of an online power system event reporting scheme. / Ph. D.
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Restabelecimento de energia em sistemas de distribuição considerando aspectos práticos / Distribution systems service restoration with the consideration of practical aspectsMarques, Leandro Tolomeu 13 June 2018 (has links)
No contexto da operação de sistemas de distribuição, um dos problemas com os quais os operadores lidam frequentemente é o de restabelecimento de energia. Este problema surge na ocorrência de uma falta permanente e pode ser tratado por meio de manobras em chaves presentes na rede primária. Uma vez que tais redes operam com topologia radial, a ocorrência de uma falta pode resultar no desligamento de consumidores saudáveis. Desta maneira, o problema consiste em definir, num curto intervalo de tempo, um número mínimo de chaves que devem ser operadas a fim de isolar a falta e restaurar o máximo de consumidores saudáveis desligados. Os esforços para a obtenção de ferramentas computacionais para fornecimento de soluções para o problema de restabelecimento têm sido intensificados nos últimos anos. Isto ocorre, em especial, devido aos enormes prejuízos causados pela falta de energia às companhias de eletricidade e a toda a sociedade. Neste sentido, o objetivo deste trabalho é a obtenção de um método para auxiliar o trabalho dos operadores através do fornecimento de planos adequados de restabelecimento em curtos intervalos de tempo. Os diferenciais deste método proposto são a sua capacidade de: lidar, em especial, com redes reais de grande porte com reduzido esforço computacional; considerar a existência de vários níveis de prioridade de atendimento entre os consumidores (note, por exemplo, que um hospital ou um centro de segurança pública devem ter maior prioridade de atendimento que um grande supermercado ou unidades residenciais) e priorizar o atendimento deles de acordo a sua prioridade; fornecer uma sequência por meio da qual as chaves possam ser operadas a fim de isolar os setores em falta e reconectar o maior número de consumidores saudáveis desligados executando-se o mínimo de manobras em chaves e priorizando os consumidores com maior prioridade; ser capaz de selecionar cargas menos prioritárias para permaneceram desligadas nas situações em que não é possível obter uma solução que restaure todas as cargas saudáveis fora de serviço; e, adicionalmente, priorizar a operação de chaves controladas remotamente, que, diferentemente das chaves controladas manualmente, podem ser operadas com menores custos e de maneira mais rápida. O método proposto consiste, de maneira sintética, na união de uma busca exaustiva aplicada localmente a um novo algoritmo evolutivo multi-objetivo em tabelas de subpopulação que faz uso de uma estrutura de dados eficiente denominada Representação Nó-Profundidade. Para avaliar a performance relativa do método proposto, simulações foram realizadas num sistema de distribuição de pequeno porte e os resultados foram comparados com os obtidos por um método de Programação Matemática. Na sequência, novos experimentos foram realizadas em diversos casos de falta na rede de distribuição da cidade de Londrina-PR e cidades adjacentes. As soluções fornecidas mostraram-se adequadas ao tratamento dos casos de falta, assim como as sequências de chaveamento associadas a elas, as quais foram capazes de priorizar o restabelecimento dos consumidores prioritários seguindo seus níveis de prioridade. Adicionalmente, estudos avaliaram a variação do tempo de processamento computacional do método proposto com a dimensão das redes de distribuições e também com o número de gerações realizadas pelo algoritmo evolutivo multi-objetivo proposto e os resultados mostraram-se satisfatórios às necessidades do problema Portanto, pode-se comprovar que o método proposto atingiu os objetivos especificados, em especial, o tratamento de aspectos práticos do problema. Além do próprio método proposto, algumas contribuições desta pesquisa são a proposição um novo algoritmo evolutivo multiobjetivo em tabelas de subpopulação e de um novo operador para manipulação de florestas de grafo armazenadas pela Representação Nó-Profundidade e voltado ao problema de restabelecimento. / In the context of distribution systems operation, service restoration is one of the problems with which operators constantly deal. It arises when a permanent fault occurs and is treated trough operations in switches at primary grid. Since distribution systems are usually radial, fault occurrence turns-off healthy customers. Thereby, the service restoration problem consists in defining, in a short processing time, the minimum amount of switches that must be operated for the isolation of the fault and reconnection of the maximum amount of healthy out-of-service customers. The efforts of developing computational tools for getting solution to this problems has increased in the last years. It is, in special, due to enormous losses caused to the utilities and to the whole society. In this sense, the main objective of this research is getting a method able to help the distribution system operator\'s work through providing service restoration plans quickly. The differentials of this research are its ability to: deal, in special, with large scale grids whit a reduced computational effort; consider costumers of several priority levels (note, for instance, a hospital has a higher supply priority in relation to a big supermarket) and prioritize the higher priority customers; provide a switching sequence able to isolate and reconnect the maximum amount of healthy out-of-service customer by the minimum amount of switching actions; select lower priority customers to keep out-of-service in order to reconnect higher priority customers when a it is not possible to restore all customers; and, additionally, prioritize switching operation in remotely controlled switches, whose operation is faster and cheapest than the operation of manually controlled switches. The proposed method mixes a local exhaustive search and a new multi-objective evolutionary algorithm in subpopulation tables that uses a data structure named Node-Depth Encoding. For evaluating the relative performance of proposed method, simulations were performed in small distribution systems and the performance was compared with the performance a Mathematical Programing method from literature. New experiments were performed a Mathematical Programing method from literature. New experiments were performed in several fault situations in the real and large-scale distribution system of Londrina-PR and adjacent cities. The solutions provided were appropriated to the treatment of such contingency situations. The same occurs with the switching sequences provided, which were able to prioritize the restoration of higher priority customers. Additional studies evaluated the variation of the running time with the size of grids and with the values adopted for the maximum number of generations of the evolutionary algorithm (which is an input parameter). The results expressed the running time of the proposed method is suitable to the problem needs. Therefore, it could be proved the proposed method achieved the specified objectives, in special, the treatment of practical aspects of the problem. Besides the proposed method, some contributions of this research are proposition of a new multi-objective evolutionary algorithm in subpopulation tables and a new reproduction operator to manipulate graph forests computationally represented by Node-Depth Encoding.
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Restabelecimento de energia em sistemas de distribuição considerando aspectos práticos / Distribution systems service restoration with the consideration of practical aspectsLeandro Tolomeu Marques 13 June 2018 (has links)
No contexto da operação de sistemas de distribuição, um dos problemas com os quais os operadores lidam frequentemente é o de restabelecimento de energia. Este problema surge na ocorrência de uma falta permanente e pode ser tratado por meio de manobras em chaves presentes na rede primária. Uma vez que tais redes operam com topologia radial, a ocorrência de uma falta pode resultar no desligamento de consumidores saudáveis. Desta maneira, o problema consiste em definir, num curto intervalo de tempo, um número mínimo de chaves que devem ser operadas a fim de isolar a falta e restaurar o máximo de consumidores saudáveis desligados. Os esforços para a obtenção de ferramentas computacionais para fornecimento de soluções para o problema de restabelecimento têm sido intensificados nos últimos anos. Isto ocorre, em especial, devido aos enormes prejuízos causados pela falta de energia às companhias de eletricidade e a toda a sociedade. Neste sentido, o objetivo deste trabalho é a obtenção de um método para auxiliar o trabalho dos operadores através do fornecimento de planos adequados de restabelecimento em curtos intervalos de tempo. Os diferenciais deste método proposto são a sua capacidade de: lidar, em especial, com redes reais de grande porte com reduzido esforço computacional; considerar a existência de vários níveis de prioridade de atendimento entre os consumidores (note, por exemplo, que um hospital ou um centro de segurança pública devem ter maior prioridade de atendimento que um grande supermercado ou unidades residenciais) e priorizar o atendimento deles de acordo a sua prioridade; fornecer uma sequência por meio da qual as chaves possam ser operadas a fim de isolar os setores em falta e reconectar o maior número de consumidores saudáveis desligados executando-se o mínimo de manobras em chaves e priorizando os consumidores com maior prioridade; ser capaz de selecionar cargas menos prioritárias para permaneceram desligadas nas situações em que não é possível obter uma solução que restaure todas as cargas saudáveis fora de serviço; e, adicionalmente, priorizar a operação de chaves controladas remotamente, que, diferentemente das chaves controladas manualmente, podem ser operadas com menores custos e de maneira mais rápida. O método proposto consiste, de maneira sintética, na união de uma busca exaustiva aplicada localmente a um novo algoritmo evolutivo multi-objetivo em tabelas de subpopulação que faz uso de uma estrutura de dados eficiente denominada Representação Nó-Profundidade. Para avaliar a performance relativa do método proposto, simulações foram realizadas num sistema de distribuição de pequeno porte e os resultados foram comparados com os obtidos por um método de Programação Matemática. Na sequência, novos experimentos foram realizadas em diversos casos de falta na rede de distribuição da cidade de Londrina-PR e cidades adjacentes. As soluções fornecidas mostraram-se adequadas ao tratamento dos casos de falta, assim como as sequências de chaveamento associadas a elas, as quais foram capazes de priorizar o restabelecimento dos consumidores prioritários seguindo seus níveis de prioridade. Adicionalmente, estudos avaliaram a variação do tempo de processamento computacional do método proposto com a dimensão das redes de distribuições e também com o número de gerações realizadas pelo algoritmo evolutivo multi-objetivo proposto e os resultados mostraram-se satisfatórios às necessidades do problema Portanto, pode-se comprovar que o método proposto atingiu os objetivos especificados, em especial, o tratamento de aspectos práticos do problema. Além do próprio método proposto, algumas contribuições desta pesquisa são a proposição um novo algoritmo evolutivo multiobjetivo em tabelas de subpopulação e de um novo operador para manipulação de florestas de grafo armazenadas pela Representação Nó-Profundidade e voltado ao problema de restabelecimento. / In the context of distribution systems operation, service restoration is one of the problems with which operators constantly deal. It arises when a permanent fault occurs and is treated trough operations in switches at primary grid. Since distribution systems are usually radial, fault occurrence turns-off healthy customers. Thereby, the service restoration problem consists in defining, in a short processing time, the minimum amount of switches that must be operated for the isolation of the fault and reconnection of the maximum amount of healthy out-of-service customers. The efforts of developing computational tools for getting solution to this problems has increased in the last years. It is, in special, due to enormous losses caused to the utilities and to the whole society. In this sense, the main objective of this research is getting a method able to help the distribution system operator\'s work through providing service restoration plans quickly. The differentials of this research are its ability to: deal, in special, with large scale grids whit a reduced computational effort; consider costumers of several priority levels (note, for instance, a hospital has a higher supply priority in relation to a big supermarket) and prioritize the higher priority customers; provide a switching sequence able to isolate and reconnect the maximum amount of healthy out-of-service customer by the minimum amount of switching actions; select lower priority customers to keep out-of-service in order to reconnect higher priority customers when a it is not possible to restore all customers; and, additionally, prioritize switching operation in remotely controlled switches, whose operation is faster and cheapest than the operation of manually controlled switches. The proposed method mixes a local exhaustive search and a new multi-objective evolutionary algorithm in subpopulation tables that uses a data structure named Node-Depth Encoding. For evaluating the relative performance of proposed method, simulations were performed in small distribution systems and the performance was compared with the performance a Mathematical Programing method from literature. New experiments were performed a Mathematical Programing method from literature. New experiments were performed in several fault situations in the real and large-scale distribution system of Londrina-PR and adjacent cities. The solutions provided were appropriated to the treatment of such contingency situations. The same occurs with the switching sequences provided, which were able to prioritize the restoration of higher priority customers. Additional studies evaluated the variation of the running time with the size of grids and with the values adopted for the maximum number of generations of the evolutionary algorithm (which is an input parameter). The results expressed the running time of the proposed method is suitable to the problem needs. Therefore, it could be proved the proposed method achieved the specified objectives, in special, the treatment of practical aspects of the problem. Besides the proposed method, some contributions of this research are proposition of a new multi-objective evolutionary algorithm in subpopulation tables and a new reproduction operator to manipulate graph forests computationally represented by Node-Depth Encoding.
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