Survey on demand side sensitivity to power quality in Ireland

Power systems require a reliable supply and good power quality. The impact of power supply interruptions is well acknowledged and well quantified. However, a system may perform reliably without any interruptions but may have poor power quality. Although poor power quality has cost implications for all actors in the electrical power systems, only some users are aware of its impact. Power system operators are much attuned to the impact of low power quality on their equipment and have the appropriate monitoring systems in place. However, over recent years certain industries have come increasingly vulnerable to negative cost implications of poor power quality arising from changes in their load characteristics and load sensitivities, and therefore increasingly implement power quality monitoring and mitigation solutions. This paper reviews several historical studies which investigate the cost implications of poor power quality on industry. These surveys are largely focused on outages, whilst the impact of poor power quality such as harmonics, short interruptions, voltage dips and swells, and transients is less well studied and understood. This paper examines the difficulties in quantifying the costs of poor power quality, and uses the chi-squared method to determine the consequences for industry of power quality phenomenon using a case study of over 40 manufacturing and data centres in Ireland.

Lebenszykluskosten von elektrischen Antriebssystemen

Insbesondere bei Antriebssystemen stehen die Energiekosten neben den Anschaffungskosten im Fokus. Jedoch bleiben weitere Folgekosten, die im Laufe des Betriebs eines Antriebssystems in einem Fördermittel entstehen, meist unberücksichtigt. Dieser Artikel beschreibt einen Ansatz, wie sich Lebenszykluskosten von Antriebssystemen in Stetigfördertechnik prognostizieren lassen. Mit Hilfe von allgemein bekannten Normen und Richtlinien kann der Lebenszyklus eines Antriebssystems von der Projektierung über die Herstellung bis zur Entsorgung nach dem Betrieb in Kostenarten eingeteilt und veranschaulicht werden. Unter Verwendung von direkter Verrechnung als auch der Kalkulation mit Prozesskosten wird eine hinreichende Genauigkeit anhand definierter Prozessketten erreicht. Auf Basis dieser Kostenkalkulationen kann ein mehrstufiges Prognosemodell gebildet werden. Somit konnten durch das entwickelnde Modell Anlagenbeispiele untersucht und berechnet werden.

Implementação de um plano de segurança de águas num hospital

Dissertação de Natureza Científica para obtenção do grau de Mestre em Engenharia Civil

TWO-PHASE HEAT TRANSFER MECHANISMS WITHIN PLATE HEAT EXCHANGERS: EXPERIMENTS AND MODELING

Two-phase flow heat exchangers have been shown to have very high efficiencies, but the lack of a dependable model and data precludes them from use in many cases. Herein a new method for the measurement of local convective heat transfer coefficients from the outside of a heat transferring wall has been developed, which results in accurate local measurements of heat flux during two-phase flow. This novel technique uses a chevron-pattern corrugated plate heat exchanger consisting of a specially machined Calcium Fluoride plate and the refrigerant HFE7100, with heat flux values up to 1 W cm-2 and flow rates up to 300 kg m-2s-1. As Calcium Fluoride is largely transparent to infra-red radiation, the measurement of the surface temperature of PHE that is in direct contact with the liquid is accomplished through use of a mid-range (3.0-5.1 µm) infra-red camera. The objective of this study is to develop, validate, and use a unique infrared thermometry method to quantify the heat transfer characteristics of flow boiling within different Plate Heat Exchanger geometries. This new method allows high spatial and temporal resolution measurements. Furthermore quasi-local pressure measurements enable us to characterize the performance of each geometry. Validation of this technique will be demonstrated by comparison to accepted single and two-phase data. The results can be used to come up with new heat transfer correlations and optimization tools for heat exchanger designers. The scientific contribution of this thesis is, to give PHE developers further tools to allow them to identify the heat transfer and pressure drop performance of any corrugated plate pattern directly without the need to account for typical error sources due to inlet and outlet distribution systems. Furthermore, the designers will now gain information on the local heat transfer distribution within one plate heat exchanger cell which will help to choose the correct corrugation geometry for a given task.

Bacterial biofilms, antibiotic resistance and healthcare-associated infections: a dangerous connection

In 2012, were estimated 6.7 million cases of healthcare-associated infections (HAI) either in long-term care facilities or acute-care hospitals from which result 37,000 deaths configuring a serious public health problem. The etiological agents are diverse and often resistant to antimicrobial drugs. One of the mechanisms responsible for the emergence of drug resistance is biofilm assembly. Biofilms are defined as thin layers of microorganisms adhering to the surface of a structure, which may be organic or inorganic, together with the polymers that they secrete. They are dynamic structures which experience different stages of organization with the ageing and are linked to an increase in bacterial resistance to host defense mechanisms, antibiotics, sterilization procedures other than autoclaving, persistence in water distribution systems and other surfaces. The understanding of bacteria organization within the biofilm and the identification of differences between planktonic and sessile forms of bacteria will be a step forward to fight HAIs.

Eficiência Energética, Gestão de Energia e Integração de Renováveis em Instalações Hospitalares

A presente dissertação é o resultado de um estudo realizado entre Março de 2015 e Março de 2016 centrado no tema Eficiência Energética nos Edifícios, no âmbito da Dissertação do 2º ano do Mestrado em Engenharia Eletrotécnica – Sistemas Elétricos de Energia no Instituto Superior de Engenharia do Porto (ISEP). Atualmente, os edifícios são responsáveis por cerca de 40% do consumo de energia na maioria dos países da europa. Energia consumida, principalmente, no aquecimento, arrefecimento e na alimentação de aparelhos elétricos. Os hospitais, como grandes edifícios, são grandes consumidores de energia e, na maioria dos países europeus, situam-se entre os edifícios públicos menos eficientes. Neste contexto, representam um tipo de edifícios cuja atividade apresenta um potencial de poupança energético importante. O tipo de atividade aí desenvolvida, aliada às especificidades do sector da saúde, faz deste tipo de edifícios um alvo de análise e otimização energética bastante apetecível. O presente trabalho passa pelo estudo do potencial para a eficiência energética de um hospital situado na zona do Porto. Foi, inicialmente, efetuado um levantamento das necessidades energéticas, de modo a identificar os sectores prioritários de atuação. Este estudo conta com a análise dos consumos obtidos através do processo de monitorização, substituição da iluminação existente por uma mais eficiente, a instalação de painéis solares para reduzir o consumo destinado às águas quentes sanitárias, a substituição de caldeira a diesel por caldeira a biomassa, substituição de um chiller por um mais eficiente, entre outros. Os consumos registados no hospital em estudo serão comparados com um plano nacional (Eficiência Energética e Hídrica no Sistema Nacional de Saúde), para, desta forma, se perceber quais os consumos do hospital em estudo, quando comparados com outros hospitais.

Contribuição à estabilidade transitória de sistemas elétricos industriais de unidades estacionárias de produção de petróleo

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Elétrica, 2015.

Quantifying the Resilience of an Urban Traffic-Electric Power Coupled System

Transportation system resilience has been the subject of several recent studies. To assess the resilience of a transportation network, however, it is essential to model its interactions with and reliance on other lifelines. In this work, a bi-level, mixed-integer, stochastic program is presented for quantifying the resilience of a coupled traffic-power network under a host of potential natural or anthropogenic hazard-impact scenarios. A two-layer network representation is employed that includes details of both systems. Interdependencies between the urban traffic and electric power distribution systems are captured through linking variables and logical constraints. The modeling approach was applied on a case study developed on a portion of the signalized traffic-power distribution system in southern Minneapolis. The results of the case study show the importance of explicitly considering interdependencies between critical infrastructures in transportation resilience estimation. The results also provide insights on lifeline performance from an alternative power perspective.

Políticas de geração distribuída e sustentabilidade do sistema elétrico

Tese (doutorado)—Universidade de Brasília, Centro de Desenvolvimento Sustentável, 2015.

THE EFFECT OF ANNEALING ON AMORPHOUS SILICON BASED SOLAR PHOTOVOLTAIC THERMAL SYSTEM (PV/T) AND APPROPRIATE GLOBAL DISPATCH STRATEGIES

Previous work has shown that high-temperature short-term spike thermal annealing of hydrogenated amorphous silicon (a-Si:H) photovoltaic thermal (PVT) systems results in higher electrical energy output. The relationship between temperature and performance of a-Si:H PVT is not simple as high temperatures during thermal annealing improves the immediate electrical performance following an anneal, but during the anneal it creates a marked drop in electrical performance. In addition, the power generation of a-Si:H PVT depends on both the environmental conditions and the Staebler-Wronski Effect kinetics. In order to improve the performance of a-Si:H PVT systems further, this paper reports on the effect of various dispatch strategies on system electrical performance. Utilizing experimental results from thermal annealing, an annealing model simulation for a-Si:Hbased PVT was developed and applied to different cities in the U.S. to investigate potential geographic effects on the dispatch optimization of the overall electrical PVT systems performance and annual electrical yield. The results showed that spike thermal annealing once per day maximized the improved electrical energy generation. In the outdoor operating condition this ideal behavior deteriorates and optimization rules are required to be implemented.

Strategic Optimization Techniques For FRTU Deployment and Chip Physical Design

Combinatorial optimization is a complex engineering subject. Although formulation often depends on the nature of problems that differs from their setup, design, constraints, and implications, establishing a unifying framework is essential. This dissertation investigates the unique features of three important optimization problems that can span from small-scale design automation to large-scale power system planning: (1) Feeder remote terminal unit (FRTU) planning strategy by considering the cybersecurity of secondary distribution network in electrical distribution grid, (2) physical-level synthesis for microfluidic lab-on-a-chip, and (3) discrete gate sizing in very-large-scale integration (VLSI) circuit. First, an optimization technique by cross entropy is proposed to handle FRTU deployment in primary network considering cybersecurity of secondary distribution network. While it is constrained by monetary budget on the number of deployed FRTUs, the proposed algorithm identi?es pivotal locations of a distribution feeder to install the FRTUs in different time horizons. Then, multi-scale optimization techniques are proposed for digital micro?uidic lab-on-a-chip physical level synthesis. The proposed techniques handle the variation-aware lab-on-a-chip placement and routing co-design while satisfying all constraints, and considering contamination and defect. Last, the first fully polynomial time approximation scheme (FPTAS) is proposed for the delay driven discrete gate sizing problem, which explores the theoretical view since the existing works are heuristics with no performance guarantee. The intellectual contribution of the proposed methods establishes a novel paradigm bridging the gaps between professional communities.

Constrained fuzzy power flow models with correlation between nodal injections

This paper extends the symmetric/constrained fuzzy powerflow models by including the potential correlations between nodal injections. Therefore, the extension of the model allows the specification of fuzzy generation and load values and of potential correlations between nodal injections. The enhanced version of the symmetric/constrained fuzzy powerflow model is applied to the 30-bus IEEE test system. The results prove the importance of the inclusion of data correlations in the analysis of transmission system adequacy.

Regulation of microgeneration and microgrids

The concept of microgrid (μGrid) has been emerging as a way to integrate microgeneration (μG) in low-voltage (LV) networks and simultaneously improve its potential benefits. Technical requirements to connect μgrids to LV networks have been studied in order to make this concept technologically feasible and safe to operate. However, the regulatory framework for economic integration of μG and μGrids on distribution systems, despite being crucial, is still an open issue. The main purpose of this paper is to contribute for the development of an appropriate economic regulation framework that removes the barriers to μG and μGrid development. To do so, the relevant costs and benefits resulting from the establishment of μG and μGrid are identified and a methodology for sharing those costs and benefits among the involved economic agents is presented. The only pre-requisite of such a methodology is the existence of a net benefit to all economic agents.

Partial discharge in power distribution electrical systems: pulse propagation models and detection optimization

Investigation on impulsive signals, originated from Partial Discharge (PD) phenomena, represents an effective tool for preventing electric failures in High Voltage (HV) and Medium Voltage (MV) systems. The determination of both sensors and instruments bandwidths is the key to achieve meaningful measurements, that is to say, obtaining the maximum Signal-To-Noise Ratio (SNR). The optimum bandwidth depends on the characteristics of the system under test, which can be often represented as a transmission line characterized by signal attenuation and dispersion phenomena. It is therefore necessary to develop both models and techniques which can characterize accurately the PD propagation mechanisms in each system and work out the frequency characteristics of the PD pulses at detection point, in order to design proper sensors able to carry out PD measurement on-line with maximum SNR. Analytical models will be devised in order to predict PD propagation in MV apparatuses. Furthermore, simulation tools will be used where complex geometries make analytical models to be unfeasible. In particular, PD propagation in MV cables, transformers and switchgears will be investigated, taking into account both irradiated and conducted signals associated to PD events, in order to design proper sensors.

Report of Technical Group on Electrical Transmission and Systems.

At head of title FCST energy R&D goals study.