The water industry is a heavy consumer of electricity to pump water. Electricity generated with fossil fuel sources produce greenhouse gas (GHG) emissions that contribute to climate change. Carbon taxation and economic discounting in project planning are promising policies to reduce GHG emissions. The aim of this research is to develop novel single- and multi-objective optimization frameworks that incorporate a new gene-coding scheme and pipe ageing models (pipe roughness growth model, a pipe leakage model, and a pipe break model) to examine the impacts of a carbon tax and low discount rates on energy use, GHG emissions, and design/operation/rehabilitation decisions in water systems. Chapter 3 presents a new algorithm that optimizes the operation of pumps and reservoirs in water transmission systems. The algorithm was applied to the KamalSaleh transmission system near Arak, Iran. The results suggest that a carbon tax combined with a low discount rate produces small reductions in energy use and GHG emissions linked to pumping given the high static head of the KamalSaleh system. Chapter 4 presents a new algorithm that optimizes the design and expansion of water distribution networks. The algorithm was applied to the real-world Fairfield water network in Amherstview, Ontario, Canada. The results suggest that a carbon tax combined with a low discount rate does not significantly decrease energy use and GHG emissions because the Fairfield system had adequate installed hydraulic capacity. Chapters 5 and 6 present a new algorithm that optimizes the optimal rehabilitation type and timing of water mains in water distribution networks. In Chapter 5, the algorithm is applied to the Fairfield network to examine the impact of asset management strategies (quantity and infrastructure adjacency discounts) on system costs. The results suggest that applying discounts decreased capital and operational costs and favored pipe lining over pipe replacement and duplication. In Chapter 6, the water main rehabilitation optimization algorithm is applied to the Fairfield network to examine the impact of a carbon tax and low discount rates on energy use and GHG emissions. The results suggest that adopting a low discount rate and levying a carbon tax had a small impact in reducing energy use and GHG emissions and a significant impact in reducing leakage and pipe breaks in the Fairfield system. Further, a low discount rate and a carbon tax encouraged early investment in water main rehabilitation to reduce continuing leakage, pipe repair, energy, and GHG costs. / Thesis (Ph.D, Civil Engineering) -- Queen's University, 2013-04-21 13:58:08.302

The operational management of Water Distribution Systems (WDS), particularly under failure conditions when the behaviour of a WDS is not well understood, is a challenging problem. The research presented in this thesis describes the development of a methodology for risk-based diagnostics of failures in WDS and its application in a near real-time Decision Support System (DSS) for WDS’ operation. In this thesis, the use of evidential reasoning to estimate the likely location of a burst pipe within a WDS by combining outputs of several models is investigated. A novel Dempster-Shafer model is developed, which fuses evidence provided by a pipe burst prediction model, a customer contact model and a hydraulic model to increase confidence in correctly locating a burst pipe. A new impact model, based on a pressure driven hydraulic solver coupled with a Geographic Information System (GIS) to capture the adverse effects of failures from an operational perspective, is created. A set of Key Performance Indicators used to quantify impact, are aggregated according to the preferences of a Decision Maker (DM) using the Multi-Attribute Value Theory. The potential of distributed computing to deliver a near real-time performance of computationally expensive impact assessment is explored. A novel methodology to prioritise alarms (i.e., detected abnormal flow events) in a WDS is proposed. The relative significance of an alarm is expressed using a measure of an overall risk represented by a set of all potential incidents (e.g., pipe bursts), which might have caused it. The DM’s attitude towards risk is taken into account during the aggregation process. The implementation of the main constituents of the proposed risk-based pipe burst diagnostics methodology, which forms a key component of the aforementioned DSS prototype, are tested on a number of real life and semi-real case studies. The methodology has the potential to enable more informed decisions to be made in the near real-time failure management in WDS.

Master of Science / Department of Electrical and Computer Engineering / Noel N. Schulz / Wind energy is becoming one of the most widely implemented forms of renewable energy worldwide. Traditionally, wind has been considered a non-dispatchable source of energy due to the uncertainty of wind speed and hence the variable availability of wind power. Advances in technology allow the consideration of the impact of distributed wind turbines and farms on distribution systems. It is possible to combine the clean energy attributes of wind with the quickly dispatchable nature of a storage facility in order to provide the maximum amount of locally available power economically to the loads present on the distribution feeder. However, a monitoring and control system needs to be provided that is capable of detecting the changes associated with the distribution feeder load and also the variable generation output from the wind farms. This task can be accomplished using a Phasor Measurement Unit (PMU) which has very high sampling rates and hence can measure very rapid and dynamic changes in power levels associated with distribution feeder load and wind generation. The data which is obtained from these PMUs can be used to calculate the amount of distributed generation and storage that can be dispatched locally at the distribution feeder, thus resulting in a reduction in the peak load levels associated with the distribution feeder as seen by the substation monitoring system. Simulations will work to balance load requirements, wind generation output, and distributed storage providing a stable system utilizing maximum renewable resources. The standard IEEE 37-node distribution test feeder is used in the study. Probabilistic models are implemented for distribution feeder load, and the models are analyzed through simulations. Four different combinations of charging and discharging methods have been investigated. Two analytically different algorithms have been used for wind and battery dispatch, one based on forecasted load information and the other based on historical measurements obtained from PMUs. The strategies being investigated can also be used to implement other important applications such as distribution system state estimation, protection and instability prediction.

Doctor of Philosophy / Department of Electrical and Computer Engineering / Sanjoy Das and Anil Pahwa / Because a majority of day-to-day activities rely on electricity, it plays an important role in daily life. In this digital world, most of the people’s life depends on electricity. Without electricity, the flip of a switch would no longer produce instant light, television or refrigerators would be nonexistent, and hundreds of conveniences often taken for granted would be impossible. Electricity has become a basic necessity, and so any interruption in service due to disturbances in power lines causes a great inconvenience to customers. Customers and utility commissions expect a high level of reliability. Power distribution systems are geographically dispersed and exposure to environment makes them highly vulnerable part of power systems with respect to failures and interruption of service to customers. Following the restructuring and increased competition in the electric utility industry, distribution system reliability has acquired larger significance. Better understanding of causes and consequences of distribution interruptions is helpful in maintaining distribution systems, designing reliable systems, installing protection devices, and environmental issues. Various events, such as equipment failure, animal activity, tree fall, wind, and lightning, can negatively affect power distribution systems. Weather is one of the primary causes affecting distribution system reliability. Unfortunately, as weather-related outages are highly random, predicting their occurrence is an arduous task. To study the impact of weather on overhead distribution system several models, such as linear and exponential regression models, neural network model, and ensemble methods are presented in this dissertation. The models were extended to study the impact of animal activity on outages in overhead distribution system. Outage, lightning, and weather data for four different cities in Kansas of various sizes from 2005 to 2011 were provided by Westar Energy, Topeka, and state climate office at Kansas State University weather services. Models developed are applied to estimate daily outages. Performance tests shows that regression and neural network models are able to estimate outages well but failed to estimate well in lower and upper range of observed values. The introduction of committee machines inspired by the ‘divide & conquer” principle overcomes this problem. Simulation results shows that mixture of experts model is more effective followed by AdaBoost model in estimating daily outages. Similar results on performance of these models were found for animal-caused outages.

Master of Science / Department of Electrical and Computer Engineering / Sanjoy Das / Anil Pahwa / Outage management describes system utilized by electric distribution utilities to help restore power in event of an outage. The complexity of outage management system employed by different utilities to determine the location of fault could differ. First step of outage management is to know where the problem is. Utilities typically depend on customers to call and inform them of the problem by entering their addresses. After sufficient calls are received, the utility is able to pinpoint the location of the outage. This part of outage management is called trouble call analysis. In event of fault in a feeder of a radial distribution system, the upstream device or the device that serves to protect that particular zone activates and opens the circuit. This particular device is considered as the operated protective device. The knowledge of the activated protective device can help locate the fault. Repair crews could be sent to that particular location to carry out power restoration efforts. The main objective of this work is to study model of distribution system that could utilize the network topology and customer calls to predict the location of the operated protective device. Such prediction would be based on the knowledge of the least amount of variables i.e. network topology and customer calls. Radial distribution systems are modeled using the immune system algorithm and test cases with trouble calls are simulated in MATLAB to test the effectiveness of the proposed technique. Also, the proposed technique is tested on an actual feeder circuit with real call scenarios to verify against the known fault locations.

Resumo: Este projeto de pesquisa tem por objetivo apresentar propostas para aprimoramento das principais normas e resoluções envolvidas, dentre as quais o PRODIST, quanto à metodologia para apuração do indicador de distorçõ de tensão harmôica total, bem como trazer contribuições para o processo de análise de compatibilidade de cargas potencialmente perturbadoras na qualidade da energia elétrica em sistemas de distribuição, através de uma visão proativa, ou seja, atuando principalmente no momento que antecede a instalação destas cargas. Estas propostas foram elaboradas a partir da análise e discussão dos resultados obtidos através dos ensaios realizados em um estudo de caso compreendendo a análise de ligação de um novo forno de indução em uma Fundição atendida por uma concessionárias de distribuição do Estado de São Paulo. Um histórico geral situando a qualidade da energia elétrica no setor elétrico é apresentado, as principais normas, resoluções e estudos técnicos são discutidos, e as diretrizes metodológicas e procedimentos utilizados nos ensaios experimentais são detalhados. A análise e discussão dos resultados é elaborada procurando responder às principais perguntas surgidas durante a investigação técnico-científica e a realização dos procedimentos, bem como indicando outros questionamentos a serem estudados, através da apresentação das propostas e indicações para trabalhos futuros / Abstract: This research project aims to present proposals for improvement of key standards and resolutions involved, among which the PRODIST, on the methodology for calculating the indicator of voltage total harmonic distortion, and should contribute to the analysis process of the potentially disturbance impacts of loads on power quality in distribution system, through a proactive vision, ie, working mainly in the moment before the installation of these loads. Those proposals were developed from the analysis and discussion of results obtained through tests on a case study including analysis of the connection of a new induction furnace in a froundry fed by a distribution utility in the State of São Paulo. A general historical situating the quality of electric energy in the sector is presented, the main standards, technical studies and resolutions are discussed, and methodological guidelines and procedures used in experimental trials are detailed. The analysis and discussion of results is prepared to answer the main questions that arise during the technical-scientific research and implementation of procedures as well as indicating other questions to be studied through the submition of proposals and directions for future work / Orientador: André Nunes de Souza / Coorientador: André Christóvão Pio Martins / Banca: Benedito Donizeti Bonatto / Banca: Pedro da Costa Junior / Mestre

Atualmente a avaliação das perdas de água, nos sistemas de distribuição, é feita com base em equações empíricas, que utilizam informações, agrupadas e totalizadas, de uma área. Isto torna necessária sua subdivisão em frações cada vez menores, na busca da fração mais crítica. Neste trabalho, é apresentada uma avaliação da eficácia do uso de modelos de simulação hidráulica na obtenção das informações necessárias para a elaboração de um diagnóstico de perdas de água, com uma metodologia prática para o uso de modelos com este objetivo. Apresenta uma classificação dos trechos de rede em três categorias A, B e C, que facilita a priorização dos trechos mais críticos facilitando a análise por meio de gráficos de pareto e mapas temáticos. Demonstra que a adoção da simulação hidráulica no estudo das causas de perdas de água, nos sistemas de abastecimento, é uma ferramenta eficaz e permitirá às empresas de saneamento, uma melhoria na gestão operacional, que garante a sustentabilidade da empresa, a economia dos recursos humanos, econômicos, e principalmente, os hídricos. / Currently water losses evaluation in distribution systems, is based on empirical equations using information, grouped and totaled, covering whole area. Thus, becomes necessary to subdivide the area into smaller and smaller fractions, searching for the most critical part. This study presents, the effectiveness evaluation of the hydraulic simulation models, use to obtain the information necessary in elaboration diagnosis of water losses, with a practical methodology for using models for this purpose. Shows a pipe classification in three categories A, B and C, its began possible analyses with pareto graphics and thematic maps. Demonstrates that hydraulic simulation adoption is an effective tool in the study of water loss in supply systems. It will allow companies an operational management improvement, ensuring the sustainability of the business and economics of human, financial, and especially, water resources.

O presente trabalho investiga metodologias para se obter automaticamente planos de restabelecimento de energia em sistemas de distribuição de energia elétrica, contemplando-se múltiplos objetivos, sendo alguns conflitantes. A redução nos índices de interrupção de energia elétrica deve ser um alvo permanente das empresas de distribuição buscando a melhoria da qualidade de fornecimento. Por outro lado, as interrupções são inevitáveis, quer para a execução de obras de manutenção preventiva, quer para obras de manutenção corretiva em virtude da ocorrência de um defeito no sistema. Depois de uma falta ter sido identificada e isolada, um plano de restabelecimento deve ser encontrado em um curto período de tempo. Devido ao problema de explosão combinatorial, técnicas de programação matemática se tornam proibitivas para esse tipo de aplicação, principalmente em sistemas de tamanho real. Por outro lado, a proposta desenvolvida de algoritmos evolucionários utilizando cadeias de grafos, têm se mostrado capaz de obter planos de restabelecimento de energia em um sistema de tamanho real no menor tempo possível. Este trabalho investiga a utilização desta metodologia para redes de grande porte sem simplificações, isto é, incluindo todas as linhas, barras e chaves do sistema. Testes são realizados em três redes de tamanhos diferentes, considerando diversos objetivos a fim de avaliar a técnica proposta. / This work investigates methodologies to automatically obtain energy restoration plans in distribution systems, involving multiple objectives that are conflicting. The reduction energy interruption indices is a permanent objective of the distribution companies in order to improve power supply. Interruptions may be carried out for maintenance or may occur due to system faults. After a fault have been identified and isolated, a restoration plan is required in a short interval of time. Due to the combinatorial explosion problem it is not possible to apply mathematical programming techniques to produce restoration plans for large networks. On the other hand, an evolutionary algorithm utilizing graph, chain has shown to be able to obtain restoration plans for real-size networks in a short interval of time. Tests are performed for three different size networks, considering several objectives to evaluate the proposed technique.

This thesis presents a research work on the development of new methodology for near-real-time detection and localisation of pipe bursts in a Water Distribution System (WDS) at the District Meters Area (DMA) level. The methodology makes use of online hydraulic model coupled with a demand forecasting methodology and several statistical techniques to process the hydraulic meters data (i.e., flows and pressures) coming from the field at regular time intervals (i.e. every 15 minutes). Once the detection part of the methodology identifies a potential burst occurrence in a system it raises an alarm. This is followed by the application of the burst localisation methodology to approximately locate the event within the District Metered Area (DMA). The online hydraulic model is based on data assimilation methodology coupled with a short-term Water Demand Forecasting Model (WDFM) based on Multi-Linear Regression. Three data assimilation methods were tested in the thesis, namely the iterative Kalman Filter method, the Ensemble Kalman Filter method and the Particle Filter method. The iterative Kalman Filter (i-KF) method was eventually chosen for the online hydraulic model based on the best overall trade-off between water system state prediction accuracy and computational efficiency. The online hydraulic model created this way was coupled with the Statistical Process Control (SPC) technique and a newly developed burst detection metric based on the moving average residuals between the predicted and observed hydraulic states (flows/pressures). Two new SPC-based charts with associated generic set of control rules for analysing burst detection metric values over consecutive time steps were introduced to raise burst alarms in a reliable and timely fashion. The SPC rules and relevant thresholds were determined offline by performing appropriate statistical analysis of residuals. The above was followed by the development of the new methodology for online burst localisation. The methodology integrates the information on burst detection metric values obtained during the detection stage with the new sensitivity matrix developed offline and hydraulic model runs used to simulate potential bursts to identify the most likely burst location in the pipe network. A new data algorithm for estimating the ‘normal’ DMA demand and burst flow during the burst period is developed and used for localisation. A new data algorithm for statistical analysis of flow and pressure data was also developed and used to determine the approximate burst area by producing a list of top ten suspected burst location nodes. The above novel methodologies for burst detection and localisation were applied to two real-life District Metred Areas in the United Kingdom (UK) with artificially generated flow and pressure observations and assumed bursts. The results obtained this way show that the developed methodology detects pipe bursts in a reliable and timely fashion, provides good estimate of a burst flow and accurately approximately locates the burst within a DMA. In addition, the results obtained show the potential of the methodology described here for online burst detection and localisation in assisting Water Companies (WCs) to conserve water, save energy and money. It can also enhance the UK WCs’ profile customer satisfaction, improve operational efficiency and improve the OFWAT’s Service Incentive Mechanism (SIM) scores.

Interruption to water services and low water pressure conditions are commonly observed problems in water distribution systems (WDSs). Of particular concern are the unplanned events, such as pipe bursts. The current regulation in the UK requires water utilities to provide reliable water service to consumers resulting in as little as possible interruptions and of as short possible duration. All this pushes water utilities toward developing and using smarter responses to these events, based on advanced tools and solutions. All with the aim to change network management style from reactive to a proactive, and reduce water losses, optimize energy use and provide better services for consumers. This thesis presents a novel methodology for efficient and effective operational, short time response to an unplanned failure event (such as pipe burst) in a WDS. The proposed automated, near real-time operational response methodology consists of isolating the failure event followed by the recovery of the affected system area by restoring the flows and pressures to normal conditions. The isolation is typically achieved by manipulating the relevant on/off valves that are located closely to the event location. The recovery involves selecting an optimal combination of suitable operational network interventions. These are selected from a number of possible options with the aim to reduce the negative impact of the failure over a pre-specified time horizon. The intervention options considered here include isolation valve manipulations, changing the pressure reducing valve’s (PRV) outlet pressure and installation and use of temporary overland bypasses from a nearby hydrant(s) in an adjacent, unaffected part of the network. The optimal mix of interventions is identified by using a multi-objective optimization approach driven by the minimization of the negative impact on the consumers and the minimization of the corresponding number of operational interventions (which acts as a surrogate for operational costs). The negative impact of a failure event was quantified here as a volume of water undelivered to consumers and was estimated by using a newly developed pressure-driven model (PDM) based hydraulic solver. The PDM based hydraulic solver was validated on a number of benchmark and real-life networks under different flow conditions. The results obtained clearly demonstrate its advantages when compared to a number of existing methods. The key advantages include the simplicity of its implementation and the ability to predict network pressures and flows in a consistently accurate, numerically stable and computationally efficient manner under both pressure-deficient and normal-flow conditions and in both steady-state and extended period simulations. The new real-time operational response methodology was applied to a real world water distribution network of D-Town. The results obtained demonstrate the effectiveness of the proposed methodology in identifying the Pareto optimal network type intervention strategies that could be ultimately presented to the control room operator for making a suitable decision in near real-time.