Surge modeling is a tool used by engineers and utility owners in determining the surge pressures or transients that may result from routine pump and valve operations. Recent surge modeling work has focused on low and/or negative pressures within water distribution systems and how those occurrences could lead to intrusions. Effective surge modeling is needed in order to determine if the intrusion potential exists and what mitigation is needed to prevent intrusions. This work focuses on the generally unexplored area of using surge models to predict the location and duration of transient induced low and/or negative pressures within large complex water distribution systems. The studied system serves 350,000 people in the southeast United States, has 65 MGD of pumping capacity at two treatment plants, over 1500 miles of main and 12 storage tanks. This work focuses on the correlation between field data and the surge model using the author's extensive operational knowledge of the system, access to real-time SCADA data, and different celerity or wave speed values. This work also traces the steps taken by the author to locate areas within the system that experienced transient induced low and / or negative pressure.

The southern Chukchi and Bering Sea region regularly experiences powerful storms that bring high winds that cause positive and negative water level set-up (storm surges) events. Positive set-up events can cause coastal inundation, sometimes extending far inland for low-relief locations, and negative set-up events can be problematic for shallow-draft marine equipment, such as barges. A ten year record (2004-2014) of water level data is available from a NOAA tide gauging station situated at the Teck Alaska Inc. Red Dog Mine Port Facility located to the north of the Bering Strait on the southwest Chukchi Sea coast. In this thesis these data are used to develop a database of water level set-up (storm surge) events using a novel identification methodology; by adapting fundamental wind storm identification concepts used by Atkinson (2005) and applying them to a water level dataset. The surge event database is then analyzed to identify primary types of events, to derive seasonal patterns and frequencies of occurrence, and to determine likely atmospheric driving mechanisms. There were 44 surge events identified – 21 positive, 23 negative – that tended to occur during the months of November, December, and January; none were recorded in the months May through August. The event typing work suggested four distinct surge patterns. Analysis of weather drivers, performed through visual interpretation of the temporal shape/form of the events and via use of an Empirical Orthogonal Function (EOF) analysis, suggested favoured locations for storm systems – the far eastern Chukotka Peninsula for positive set up events (west of Red Dog Dock), and the Alaska Peninsula for negative set ups (south of Red Dog Dock). A storm system situated to the west of the port generates southwest winds that drive positive set-up events, and a storm situated to the south generates easterly winds that drive negative set-up events. The sea level pressure weather patterns for positive set-up surge events are much stronger and shorter lived than for negative set-up events. This work has established an improved understanding of seasonal storm surge for the region and offers a potential basis for the improved forecasting of both positive and negative set-up surge events in the future. / Graduate / 0725

More frequent and harsh storms coupled with sea level rise are affecting Canada’s sensitive coastlines. This research studies Isle Madame in Cape Breton, Nova Scotia which has been designated by Natural Resource Canada as a sea level rise vulnerable coastal community in Canada. The research models the spatial and temporal impacts of sea level rise from storm surge by focusing on identifying vulnerable areas in the community via geographical information systems (GIS) using ArcGIS, as well as modeling dynamic coastal damage via system dynamics using STELLA. The research evaluates the impacts in terms of the environmental, social, cultural, economic pillars that profile the coastal community for a series of modelled Storm Scenarios. This research synthesizes information from a variety of sources including the coastal ecology and natural resources, as well as human society and socioeconomic indicators included in the four mentioned pillars. The objective of the research is to determine vulnerable areas on Isle Madame susceptible to storm damage, and consequently, to improve local community knowledge and preparedness to more frequent harsh storms. This research therefore presents a dynamic model for the evaluation of storm impacts in Isle Madame designed with the goal to help the community ultimately to plan and implement a strategy to adapt to pending environmental change.

CHDS State/Local / This thesis addresses the role of the emergency department in planning for mass casualties during an emergency. The demand on hospital emergency departments has stretched the capacity for normal operations beyond their original design. Hospital surge capacity is not only complex, but affects every hospital emergency department in the country. Factors, such as hospital bed capacity, surge levels, staffing and the use of volunteers in time of emergency, all play a critical role in the ability and accessibility of the hospital to react during times of need. The recommendations provided are based on the analysis of county, state and federal plans along with case studies that provide a varied approach to emergency preparedness and the role of the hospital, focus on some of the facets of preparedness and the immediate need for emergency planning, training/exercising and communication in hospitals across America, and specifically, in hospitals in South Carolina.

This thesis examines how residents perceived and coped with storm surge flooding in Tsawwassen, British Columbia. On February 4, 2006 the community experienced a storm surge flood that affected residents within the neighbourhoods of Beach Grove and Boundary Bay Village. This study identifies how residents perceived and coped with the flood, and what factors influenced how individuals perceived and coped. Qualitative methods were used for this study, and a total of 23 in-person interviews were completed. The findings of this research showed that how participants perceived the threat of storm surge flooding and how they coped with the flooding varied greatly. Government intervention; the influence of family, friends and neighbours; the perceived benefits of living in the area; experience; financial support; and perception of other hazards all influenced how the participants perceived and coped with the storm surge flood.

Sea-level rise and stronger hurricanes associated with global climate change will likely result in farther reaching storm surges that will greatly affect coastal ecosystems. These surges can transport nutrients, salt water, and sediment to nutrient poor, fresh (i.e. low salinity) pine savannas. Purple pitcher plants (Sarracenia purpurea ) are pine savanna inhabitants that could potentially be at a disadvantage because their pitcher morphology and stout structure may leave them prone to collecting saline water and sediment after a surge. In this study, separate field and greenhouse experiments were conducted to test the effects of storm surge water salinity and sediment type on pine savanna soil characteristics, plant community structure, and pitcher plant vitality. In the field, plots (containing &ge genet of S. purpurea ) were experimentally storm surged with fresh or saline water crossed with one of four sediment types (local, foreign, fertilized foreign, or no sediment). Saline water inundation resulted in significantly higher pitcher plant mortality than the fresh water treatment combinations. However, a subsequent prescribed fire and regional drought affected the study area during the next growing season, resulting in the decline of all the pitcher plants to zero or near zero percent cover. Soil data revealed that the combination of salt water and fertilized sediment resulted in short-term increases in soil-water conductivity and nitrogen availability. Interestingly, there were no significant differences in plant community structure between treatments, suggesting that the community as a whole is not as vulnerable as the pitcher plants to the cumulative effects of multiple stressors (i.e. storm surge, fire, and drought) operating in this system. Indicator species analysis revealed that some species were significant indicators of certain treatments; thus suggesting that pitcher plants are not the only species affected by storm surge. In the greenhouse, pitcher plants received various forms of sediment (i.e. no sediment, sterile sediment, or one of two levels of fertilized sediment) within their pitchers to determine if nutrient uptake is either inhibited or enhanced. Plants that received sterile sediment had higher carbon:nitrogen ratios and higher leaf mass per unit area. Eutrophic sediment deposition resulted in a temporary decrease in relative growth rate as well as changes in pitcher morphology. There were no differences in chlorophyll content and photosynthetic rates between treatments. Both the field and greenhouse experiments indicate that global climate change may indirectly contribute to the further decline of southeastern purple pitcher plant populations in the future.

Orientador: Maria Cristina Dias Tavares / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-10T09:40:09Z (GMT). No. of bitstreams: 1 MestasValero_Patricia_M.pdf: 3064250 bytes, checksum: 898053aa51c68fc5e5e170f255fa1d05 (MD5) Previous issue date: 2007 / Resumo: As sobretensões em um sistema de transmissão não podem ser evitadas assim como a sua total supressão é extremamente difícil, entretanto, suas amplitudes podem ser reduzidas. Tradicionalmente, as sobretensões transitórias advindas das manobras de energização e religamento de linhas de transmissão são limitadas utilizando o ¿método convencional¿ como é o caso do uso de resistores de pré-inserção, este apesar de ser um método efetivo, apresenta uma aceitação de sua tecnologia tendente a diminuir devido ao alto custo de implementação e manutenção. Nos últimos tempos as principais empresas de transmissão do mundo têm se mostrado mais favoráveis a utilização de pára-raios e chaveamento controlado de disjuntores para o controle de sobretensões, mas na prática esta aplicação está apenas sendo iniciada. O presente trabalho foi realizado com o objetivo de analisar os diferentes métodos para o controle de sobretensões associadas às manobras de energização e religamento trifásico de linhas de transmissão em vazio determinando assim as melhores condições técnicas para a otimização destes processos. Apresentam-se os resultados obtidos através de simulações com o programa PSCAD/EMTDC de um caso específico com dados reais dos geradores, transformadores, características dos trechos de linhas de transmissão, pára-raios e reatores de compensação em derivação tendo como base um sistema de 500 kV / Abstract: The switching transient in transmission system cannot be prevented as well as its total suppression is extremely difficult, however, its magnitudes have to be limited. For long transmission lines, traditionally the switching transient overvoltages due to energization and reclosure are limited by the ¿conventional method¿ as is the case of preinsertion resistors in the line circuit breakers. Although this is an effective mitigation method it presents a decreasing acceptance due to the high cost of implementation and maintenance. Recently, important transmission firms in the world have shown the trend to the use of surge arresters and controlled switching breakers, in practical this application is only being initiated. The present work was realized with the objective of analyzing the different methods for the overvoltages control associates to energization and three-phase reclosing maneuvers of transmission lines to determine the best technique for the optimization of these processes. The results was obtained through digital simulations with PSCAD/EMTDC software for an specific case with real dates for generators, transformer, transmission lines, surge arresters and shunt compensation reactors of a 500 kV system / Mestrado / Energia Eletrica / Mestre em Engenharia Elétrica

Este trabalho tem como objetivo propor e avaliar um novo método para controle antissurto de compressores dinâmicos. É sabido que compressores dinâmicos são sujeitos ao fenômeno de surto, o qual pode danificar gravemente os componentes do compressor e provocar distúrbios de produção. O surto pode surgir a partir da ocorrência de distúrbios (por exemplo, fechamento da válvula de descarga do compressor) os quais, sem ação antissurto, fariam com que o ponto de operação se deslocasse para uma região de baixas vazões delimitada por uma linha conhecida como linha de surto. Portanto, compressores dinâmicos sempre são equipados com mecanismos antissurto: tipicamente uma válvula de reciclo de ação rápida controlada por um controlador PI antissurto. Dado que o surto se desenvolve extremamente rápido, usualmente não se permite que o compressor opere muito próximo da linha de surto. Esse objetivo de controle (manter o compressor afastado da linha de surto) é conflitante com objetivos de eficiência energética, pois os pontos de maior eficiência estão localizados próximos a essa linha. Logo, é desejável operar o compressor utilizando a mínima margem de surto que ainda garanta que a ação antissurto seja efetiva. Este trabalho propõe um método para ativação da ação antissurto no compressor com o objetivo de atingir uma ação mais rápida que o controle PI tradicional. O método proposto se baseia no cálculo offline das aberturas necessárias para a válvula de reciclo para cada possível combinação das posições dos atuadores do sistema, considerando um conjunto discreto pré-definido de valores dentro da faixa de valores de cada atuador. Esse processo gera uma tabela auxiliar para uso online. Os valores da tabela auxiliar são utilizados para gerar valores de referência para um controlador por realimentação, o qual é responsável por garantir que a trajetória do sistema irá do estado inicial no momento da ativação do controle antissurto para o estado estacionário desejado. Diversos cenários de distúrbio são simulados para diferentes controladores por realimentação e comparados com o controle antissurto PI tradicional. Os resultados mostram que a estratégia proposta é um candidato para melhorias na prática atual de controle antissurto, mas um controle por realimentação adequado deve ser selecionado e avaliado também considerando o aspecto de robustez, o qual é brevemente considerado no escopo deste trabalho. / This work aims at proposing and evaluating a novel method for anti-surge control of dynamic compressors. Dynamic compressors are known to suffer from surge, which can severely damage compressor components and disturb production. Surge may arise by the occurrence of disturbances (e.g. compressor discharge valve closure) that would bring its operating point to a region at low flows delimited by the so called surge line. Therefore, dynamic compressors are always equipped with anti-surge mechanisms: typically a fast actuating recycle valve controlled by a PI anti-surge controller. Since surge develops extremely fast, the compressor is usually not allowed to operate too close from the surge line. This control objective (keep the compressor away from the surge line) is conflicting with energy efficiency requirements, since higher efficiency operating points are located close to the surge line. Therefore, it is desirable to operate the compressor using the smallest possible surge margin that still guarantees anti-surge action is effective. This work proposes a method for triggering the compressor anti-surge action, aiming at a faster action than traditional PI control. The proposed anti-surge control method relies on an offline computation of necessary recycle valve openings for each possible combination of the system actuators positions, considering a predefined discrete set of values from the actuators positioning ranges. This generates a look-up table for online use. The values from the look-up table are used to identify the necessary compressor flow set-point for a feedback controller, which is responsible for ensuring that the system trajectory goes from the state upon anti-surge activation to the desired steady state. Several disturbance scenarios are simulated for different feedback controllers and compared to the traditional PI anti-surge controller. Results show that the proposed strategy is a candidate for improvements in current anti-surge control practice but an adequate feedback control strategy must be chosen and evaluated also under the consideration of robustness, which is slightly considered in the scope of this work.

Orientador: José Pissolato Filho / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-24T06:21:09Z (GMT). No. of bitstreams: 1 Abreu_SandersonRochade_M.pdf: 5297087 bytes, checksum: ef0820d93a3ed019ef6405a29a95a6c0 (MD5) Previous issue date: 2013 / Resumo: Os sistemas elétricos estão submetidos esporadicamente a várias formas de fenômenos transitórios, envolvendo variações súbitas de tensão e de corrente provocadas por descargas atmosféricas, faltas no sistema ou operação de disjuntores e chaves seccionadoras. Desta forma, os equipamentos elétricos além de estarem permanentemente solicitados pela tensão de operação dos sistemas, serão eventualmente submetidos por solicitações de tensões temporárias e transitórias, provenientes da ocorrência de distúrbios nos sistemas. A utilização de para-raios em sistemas de distribuição é uma prática que as empresas distribuidoras de energia elétrica vêm utilizando ao longo dos anos, para limitar as amplitudes das sobretensões transitórias de origem atmosférica nos sistemas de distribuição, reduzindo os efeitos dessas sobretensões sobre os equipamentos a níveis aceitáveis, de modo a aumentar a confiabilidade do sistema. Para isso, é imprescindível que os para-raios estejam operacionais ao longo de toda a sua vida útil e que resistam às diversas solicitações de tensões temporárias e transitórias sob diferentes condições ambientais. Este trabalho, pretende avaliar o comportamento dos diferentes projetos construtivos de para-raios de distribuição disponíveis no mercado nacional e internacional, mediante a avaliação sob condições de temperatura, umidade e precipitação pluviométrica, por meio de envelhecimento acelerado. Pretende fornecer subsídios que possam nortear escolhas importantes a serem tomadas pelas concessionárias de distribuição de energia elétrica do Grupo Energisa, como por exemplo, a seleção do equipamento adequado às condições climáticas de cada região atendida. A análise da hidrofobicidade dos polímeros utilizados na construção do para-raios tem um papel importante neste trabalho, pois poderá indicar a possível degradação do invólucro de acordo com as condições ambientais que este está exposto por região do Brasil, onde o Grupo Energisa tem atuação / Abstract: The eletrical systems are sporadically submitted to several forms of transient phenomena involving sudden changes in voltage and current caused by atmospheric surges, system faults or operating circuit breakers and switchgear. Thus, electrical equipment in addition to being permanently operating voltage required by the systems, are eventually submitted to requests for temporary and transient voltages, from the ocurrence of systems disturbances. The use of surge arresters in distribution systems is a practice that the electricity distribution companies have used over the years to limit the amplitudes of transient overvoltages of atmospheric origin in distribution systems and reducing the effects of these overvoltages on equipment at acceptable levels in order to increase system reliability. Therefore, it is necessry that surge arresters are operational throughout its life and resistant to several requests of temporary and transient voltages under different environmental conditions. This work intends to evaluate the behavior of different constructive projects of surge arresters distribution available on the national and international markets, through their evaluation under conditions of temperature, humidity and rainfall, through accelerated aging. Also intends to provide subsidies to orient important choices to be made by electricity distribution companies from Energisa Group, for example, the selection of appropriate climatic conditions equipment of each region served. For this, the analysis of the hydrophobicity of the polymers used in the construction of surge arresters, plays an important role in this work , as it may indicate the possible deterioration of the housing according to the environmental conditions that are exposed by the region of Brazil, where the Group Energisa has operations / Mestrado / Energia Eletrica / Mestre em Engenharia Elétrica

[pt] Os compensadores estáticos são equipamentos modernos que estão sendo cada vez mais utilizados nos sistemas de potência. Existem basicamente três tipos de compensadores estáticos: reatores saturáveis, reator controlado e tiristores (RCT) e capacitor chaveado a tiristores (CCT). Os dois últimos são compostos basicamente por reatores, capacitores, válvulas de tiristores e um sistema de controle. As válvulas de tiristores e o sistema de controle são os itens tecnologicamente mais importantes e representam cerca de 30% do custo. Por isso este trabalho aborda um dos aspectos mais importante do projeto da válvula; as sobretensões de comutação. Estas sobretensões ocorrem repetitivamente nas condições normais de operação e são inerentes às características do equipamento e às características dos tiristores. Este trabalho analisa a influência destas características e apresenta um modelo digital de tiristor que permite representar detalhadamente estas sobre tensões. Finalmente, os resultados obtidos com este modelo e com o programa SPICE são comparados com a análise teórica e com resultados medidos em laboratório. / [en] The Static Var Compensators are modern equipments which are been more and more used in power systems. There is three types of static var compensators; saturable reactors, thyristor controlled reactors and thyristor switched capacitors. The thyristor valves and control system are, from the technological point view, the most important items of the last two types and represent about 30% of its cost. Therefore, this work treats with one of the most important aspects of the design of thyristor’s valves; the commutation overvoltages. These overvoltages occur repeatedly under normal conditions and are caused by intrinsic characteristics of the equipment and by the intrinsic characteristics of the thyristors. This works analyses the influence of these characteristics and presents a thyristor digital model which permits the detailed representation of these overvoltages. Finally, the results obtained with this model and with the digital program SPICE are compared with the theoretical analysis and with measured results.