The Million Program, buildings built between 1965 - 1974, is still a large part of the Swedish housing stock. These buildings now face a major need for renovation and energy efficiency measures. At the same time as the need for renovation is increasing, photovoltaic systems have also grown in popularity. The growing renovation need in combination with the increased popularity of photovoltaic systems has led to increased interest for whether photovoltaic systems panels can be mounted on existing buildings. The purpose of this study is to examine the potential problems when investigating the conditions for and the mounting of photovoltaic systems on existing roofs with respect to building statics. The focus is on buildings built during the million program and how the roof structure of these buildings is affected by the extra load from photovoltaic systems panels. A case study was performed where the strength of a roof with a time-typical roof construction from the million program was computed. A comparison of the characteristic loads according to European design rules and Swedish building standards was also carried out to give a perspective on differences in the standards. A number of interviews were conducted with various parties within the construction industry on the problem of photovoltaic system panel installations. The result of the case study shows that the roof does not withstand the new load in form of photovoltaic system panels according to the European design rules. When comparing the norms, it turns out that the main difference between them is that European design rules have a significantly higher characteristic snow load compared to the Swedish building norm. It can be concluded that European design rules generally have higher characteristic loads than the Swedish building norm, which can make the installation of photovoltaic system panels on houses built according to Swedish building norm more difficult due to the fact that the expansion have to be calculated according to the European design rules. Another major problem when investigating if photovoltaic system panels can be installed on typical roofs from the million program era, is lack of as-built documentation. / Miljonprogrammet, byggnader som byggdes mellan 1965 - 1974, är än idag en stor del av det svenska bostadsbeståndet. Dessa byggnader står idag inför ett stort renoverings- och energieffektiviseringsbehov. Samtidigt som behovet av renovering ökar har också solceller ökat i popularitet. Det ökande renoveringsbehovet i kombination med den ökade populariteten av solceller har lett till att efterfrågan på huruvida det går att montera solcellsmoduler på befintliga byggnader har ökat. Syftet med denna studie är att undersöka vad det finns för problematik kring utredning och montering av solcellsmoduler på befintliga tak med hänsyn till byggstatik. Fokuset ligger på byggnader uppförda under miljonprogrammet och hur byggnaders takkonstruktion blir påverkad av den extra lasten som solcellspanel innebär. En fallstudie har utförts där hållfastheten för ett tak med en tidstypisk takkonstruktion för miljonprogrammet beräknas. En jämförelse mellan de karakteristiska lasterna enligt Europeiska konstruktionsregler respektive Svensk byggnorm har även utförts för att ge en bild av skillnader och likheter mellan normerna. Ett antal intervjuer har också utförts med olika parter inom byggbranschen för att få reda på vad de ser för potentiell problematik kring installation av solcellsmoduler. Resultatet från fallstudien visar att takkonstruktionen som utsätts för den nya lasten i form av solcellspaneler inte håller enligt Europeiska konstruktionsregler. I jämförelsen av normerna visar det sig att den största skillnaden mellan dem är att Europeiska konstruktionsregler har en betydligt högre karakteristisk snölast jämfört med Svensk byggnorm. Även vindlasten skiljer sig mellan normerna. Likhet finns i nyttig last och egentyngd mellan normerna, där finns ingen nämnvärd skillnad. Det går att dra slutsatsen att Europeiska konstruktionsregler generellt har högre karakteristiska laster än Svensk byggnorm.

<p>This research presents thermal image analysis for Fault Detection and Diagnosis (FDD) of Photovoltaic (PV) Systems. The traditional manual approach of PV inspection is generally more time-consuming, more dangerous, and less accurate than the modern approach of PV inspection using Aerial Thermography (AT). Thermal image analysis conducted in this research will contribute to utilizing thermography and UAVs for PV inspection by providing a more accurate and cost-efficient diagnosis of PV faults. In this research, PV module inspection was achieved through two steps: (i) PV monitoring and (ii) PV Fault Detection and Diagnosis (FDD). In the PV monitoring stage, PV cells were monitored by aerial thermography. In this stage, the thermal data was acquired for the next step. In the PV FDD stage, hot spot phenomenon and the condition of the PV modules were detected and measured. The proposed research will help with the problems of the modern PV inspection and, eventually, contribute to the performance of PV power generation.</p>

Deep learning has proven to be a valued contributor to recent technological advancements within energy systems. This thesis project explores methods of photovoltaic (PV) system power output forecasting through the utilization of long short-term memory (LSTM) neural networks. An encoder-decoder architecture (ED-LSTM) and a stacked vector output architecture (SVO-LSTM) were compared in terms of their ability to accurately produce power output forecasts with a 24-hour forecast horizon. The datasets which were used for model training were composed of historical meteorological observations and PV system power output readings. The results indicate that the encoder-decoder model and the stacked vector output model were somewhat equally skilled at producing power output forecasts. Best results were obtained by the encoder-decoder LSTM model which achieved a 26.63% improvement over a persistence model when trained on data sequences which preceded the forecast horizon, and a 44.96% improvement over a persistence model when the model was provided meteorological data from an oracle forecaster.

This Master’s thesis deals with the problems of small domestic appliances in solar systems. The theoretical part provides a description of solar thermal systems and solar photovoltaic systems, including the possibility of their combination. It adds options connecting the small household appliances in system of solar technology and economics of the washing process. The practical part evaluates the economy of operation small household appliances connected to the solar system.

M. Tech. (Engineering, Electrical, Department Electronic Engineering, Faculty of Engineering and Technology), Vaal University of Technology / In order to facilitate sustainable development, it is necessary to further improve and increase the energy efficiency and use of renewable energy and its related technologies. The main limiting factors to the extensive use of photovoltaic (PV) modules include the high initial investment cost and the relatively low conversion efficiency. However, other factors, such as an increase in ambient temperature, exert a considerable negative influence on PV modules, with cell efficiencies decreasing as the cell’s operating temperature increases. Higher PV module surface temperatures mean lower output voltages and subsequent lower output power. Therefore, this dissertation focuses on optimizing the available output power from a PV module by investigating and controlling the effect that the PV module’s surface temperature exerts on the amount of electrical energy produced. A pilot study was conducted by using a PV module set to three different tilt angles with an orientation angle and temperature sensors placed at different points. This was done to determine temperature distribution on the PV module surfaces as well as identify which tilt angle produces the highest PV module surface temperature. The main study was designed to investigate the electrical performance of a PV module with different cooling systems (water and forced air) as against a referenced measurement (no cooling). The cooling systems will be switched on and off at specific time intervals with the help of an electronic timer circuit incorporating a PIC microcontroller. The pilot study was conducted for a 50 week period where the results indicated a direct correlation between temperature rise and voltage decrease. The PV module’s temperature is highest at a tilt angle of 16° during the day and lowest at night time. It further reveals that the PV module’s front and back surface temperature can be distinctly different, with the highest recorded values occurring at the back of the PV module. The main study was conducted for a period of 15 weeks with results indicating that the water cooling system resulted in an average higher output power of 49.6% when compared to the reference system (no cooling system). Recommendations are made that sufficient space should be included between the module frames and mounting structure to reduce high operating temperatures owing to poor air circulation.

La situation compromettante de l'environnement due à la pollution, et les coûts élevés des combustibles fossiles ont engagé des nouvelles politiques et réglementations et ont fortement incité l’augmentation de l’utilisation de nouvelles sources d'énergie renouvelables. De nombreux pays dans le monde ont augmenté de façon importante le développement de ces sources d'énergie. Deux des systèmes d'énergies renouvelables les plus couramment utilisés sont les systèmes éoliens (SE) et les systèmes photovoltaïques (SP). SE convertissent l'énergie du vent en énergie électrique au moyen d'un processus électromécanique et SP convertissent directement l'énergie solaire en énergie électrique au moyen d'un processus semi-conducteur. Ces systèmes présentent de nombreux défis qui doivent être résolus afin de gagner du terrain sur les systèmes d'énergies traditionnelles. L'un de ces défis est d'augmenter l'efficacité du système avec la commande des éléments de puissance. Afin d'atteindre cet objectif, il est nécessaire de mieux comprendre le comportement dynamique de ces systèmes et de développer des nouveaux modèles mathématiques et des nouvelles techniques de commande. Ces techniques nécessitent souvent des informations du système qui ne sont pas disponibles --- ou sont trop chères si on devait les mesurer. Pour résoudre ce problème, il est nécessaire de créer des algorithmes qui puissent estimer cette information, cependant, ce n'est pas une tâche facile, car les signaux des sources d'énergie dans SE et SP (c.-à-d. la vitesse du vent, rayonnement solaire, température) entrent dans les modèles mathématiques par une relation non linéaire. Ces algorithmes doivent pouvoir estimer ces signaux --- ou les signaux qui dépendent d’eux--- avec une bonne précision. Aussi, il est nécessaire de concevoir des lois de commande qui opèrent les systèmes à leur point maximum de puissance. Dans ce travail, nous proposons des nouveaux algorithmes d'estimation et des lois de commande qui sont liés à l'augmentation de l'efficacité énergétique dans SE et SP. Des travaux antérieurs liés à l'estimation des signaux mentionnés, les considéraient comme constants. Dans cette thèse, les algorithmes d'estimation proposés considèrent l'état variable des ces signaux. Dans toutes ces nouvelles propositions, la stabilité asymptotique est prouvée en utilisant les théories de Lyapunov. Les lois de commande sont calculées en utilisant les modèles non linéaires des systèmes. En outre, certaines des ces solutions sont étendues au cas général, qui peut être utilisé sur une large classe des systèmes non linéaires. Le premier, est un estimateur de paramètres pour les systèmes non linéaires. Il permet d'estimer les paramètres non linéaires variant dans le temps. La deuxième proposition est la conception d’un schéma pour une classe de systèmes non linéaires adaptatifs qui permet de compenser les incertitudes et les perturbations qui satisfont à la "condition de correspondance". / The compromising situation of the environment due to pollution, and the high costs of the fossil fuels have originated new policies and regulations that have stimulating the interest on alternative energy sources. Many countries around the world have increased in an important way the penetration of these energy sources. Two of the most widely used renewable energy systems are the wind turbines systems (WTS) and the photovoltaic systems (PVS). WTS convert wind energy in electric energy by means of an electromechanical process and PVS convert solar energy directly in electric energy by means of a semiconductive process. These systems show many challenges that need to be solved in order to gain ground to the traditional energy systems. One of these challenges is increase the overall system efficiency by controlling the power conditioning elements. In order to achieve this, is necessary to better understand the dynamic behavior of these systems and develop new mathematical models and new control techniques. These techniques often require system information that is not possible ---or is too expensive--- measure. In order to solve this problem, is necessary to create algorithms that are able to estimate this information, however, this is not an easy task, because the signals of the energy sources in WTS and PVS (i.e., wind speed, irradiance, temperature) enter in the mathematical models in a nonlinear relation. These algorithms have to be able to estimate these signals ---or the signals that depend on them--- with good precision. Also, it is necessary to design control laws that operate the systems at their maximum power point. In this work, we propose novel estimation algorithms and control laws that are related with the increase of the energetic efficiency in WTS and PVS. Previous works related with estimation of the mentioned signals considered them as constants. In this thesis, the proposed estimation algorithms consider the time-varying condition of these signals. In all of these novel propositions, uniform asymptotic stability is proved using Lyapunov theories. The control laws are derived using the overall nonlinear models of the systems. In addition, some of these solutions are extended to the general case, which can be used on a large-class of nonlinear systems. The first one, is a novel parameter estimator for nonlinear systems. It allows to estimate time-varying nonlinear parameters. The second general proposition is a framework for a class of adaptive nonlinear systems that allows to compensate for uncertainties and perturbations that satisfy the matching condition.

Este trabalho apresenta abordagens para a avaliação do fenômeno da Degradação Induzida pelo Potencial (PID do inglês Potential Induced Degradation) em módulos e instalações fotovoltaicas de c-Si. Nos ensaios em laboratório, a IEC TS 62804-1:2015 foi aplicada e ações adicionais são sugeridas como forma de adaptação da especificação técnica para o acompanhamento da degradação durante o ensaio e para melhor indicar a propensão do equipamento a se recuperar das consequências da aparição de PID. Nos ensaios em campo, avaliou-se a solução convencional do mercado de reverter a degradação através de circuitos anti-PID, além de apresentar a aplicação de técnicas de detecção do fenômeno em sistemas operacionais. A abordagem teórica e os resultados práticos mostram que o procedimento de aferição de tensões individuais de operação é um método útil para detectar PID. Os estudos de caso apresentados indicam que esta metodologia é eficaz inclusive na detecção precoce do fenômeno para diferentes topologias de células fotovoltaicas de c-Si. / This work presents approaches to assess the Potential Induced Degradation (PID) on c-Si photovoltaic modules and installations. The IEC TS 62804-1:2015 was applied to the laboratory tests and some additional actions are suggested. The adaptation of the technical specification aims to monitor the degradation rates during the tests and also to consider the capacity of the photovoltaic modules to recover from the degradation. In the field detection methodologies are presented and anti-PID circuits were also tested. The theoretical approach reveals that individual voltage measurements are useful to detect PID even in its early stage, as can be seen on the case studies presented.

Skolfastigheter is a municipality owned real estate company that manages most of the buildings used for lower education in Uppsala. The company is working in line with the environmental goals of the municipality by installing photovoltaic systems in schools and other educational buildings. Skolfastigheter are planning to install a photovoltaic system in a school in Stenhagen. The purpose of this study is to optimally design the proposed system. The system will be maximized, which in this study entails that the modules will be placed on every part of the roof where the insolation is sufficient. The system will also be grid connected. The design process includes finding an optimal placement of the modules, matching them with a suitable inverter bank and evaluating the potential of a battery storage. Economic aspects such as taxes, subsidies and electricity prices are taken into account when the system is simulated and analyzed. A sensitivity analysis is carried out to evaluate how the capacity of a battery bank affects the self-consumption, self-sufficiency and cost of the system. It is concluded that the optimal system has a total peak power of almost 600 kW and a net present value of 826 TSEK, meaning that it would be a profitable investment. A battery bank is excluded from the optimal design, since increasing the capacity of the bank steadily decreased the net present value and only marginally increased the self-consumption and self-sufficiency of the system.

No Brasil, a necessidade crescente por sistemas de geração solar fotovoltaica conectados à rede de distribuição levou ao desenvolvimento de normas brasileiras para a conformidade de inversores. Assim, de forma a atender a população em geral, foi publicada a Portaria 357, de 01 de agosto de 2014, do Instituto Nacional de Metrologia, Qualidade e Tecnologia (INMETRO), que inclui inversores para conexão à rede de potência nominal até 10 kW no Programa Brasileiro de Etiquetagem (PBE). Por possuir os equipamentos necessários para a realização dos ensaios de conformidade com a portaria 357, o Laboratório de Sistemas Fotovoltaicos (LSF) do Instituto de Energia e Ambiente da Universidade de São Paulo passa então a ser o primeiro laboratório acreditado pelo INMETRO para a realização desses ensaios. Este trabalho tem como objetivo resumir as experiências de aplicação das normas brasileiras no ensaio de inversores para o PBE no LSF, sendo levantados os resultados obtidos no ensaio de 15 inversores ao longo de três anos de operação da bancada de ensaio para sistemas conectados à rede. A partir deste levantamento conclui-se que, embora as normas brasileiras exijam rigor em seus requisitos, existem inversores capazes de atender aos requisitos normativos brasileiros, assim como existem inversores que necessitam de implementações nos respectivos firmware de controle para conseguirem atender todos os requisitos. Uma vez que as normas brasileiras são recentes, este trabalho também destaca pontos das normas que se beneficiariam de adequações no corpo do texto, a fim de melhorar as rotinas de ensaios em inversores e critérios de conformidade. / In Brazil, the increasing demand for grid-tie photovoltaic systems lead to the development of the Brazilian standards for inverter quality and evaluation. In order to meet the general population demand, the National Institute for Metrology, Quality and Technology (INMETRO) published the normative nº 357 01/08/2014 to include inverters up to 10 kW in the Brazilian Labeling Program (PBE). For having all the equipment needed for inverter conformity evaluation in accordance with the normative nº 357, the Laboratory of Photovoltaic Systems (LSF) of the Institute of Energy and Environment of the University of Sao Paulo becomes the first INMETRO accredited laboratory for conducting the inverter evaluation in Brazil. This works main goal is to summarize the experience acquired for the appliance of the Brazilian standards for inverter testing in the LSF. The results obtained for the test of 15 different inverters during the first three years operating the inverter test bench are showed. Using the data shown this work concludes that, although the Brazilian standards are rigorous on its criteria, there are inverters capable of complying with the standards requirements and there are inverters that need further software and hardware development in order to comply with all the requirements. Since the Brazilian standards are in its first version, this work also aims to point out aspects of the standard that would benefit from text revising in order to improve the test conditions and conformity criteria.

Submitted by Franciele Moreira (francielemoreyra@gmail.com) on 2018-03-27T12:32:47Z No. of bitstreams: 2 Dissertação - Thaissa de Melo Cesar - 2018.pdf: 17977918 bytes, checksum: aef850db04513a76a546a025583e8e42 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-03-27T14:27:07Z (GMT) No. of bitstreams: 2 Dissertação - Thaissa de Melo Cesar - 2018.pdf: 17977918 bytes, checksum: aef850db04513a76a546a025583e8e42 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-03-27T14:27:07Z (GMT). No. of bitstreams: 2 Dissertação - Thaissa de Melo Cesar - 2018.pdf: 17977918 bytes, checksum: aef850db04513a76a546a025583e8e42 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-03-09 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This work presents a study on the application of the wavelet transform in the monitoring and analysis of the power quality and in the detection of islanding conditions in distributed generation systems, addressing a grid connected photovoltaic system as a case study. Initially, an introduction about distributed generation systems, standards and requirements for operation was made. Next, the concepts and parameters related to electric power quality and islanding conditions are presented. Then a review of the wavelet transform is presented, showing the concept of multiresolution analysis and the main applications in the topic addressed. The wavelet transform is an important contribution to time-frequency localization methods for the analysis of transient signals. A multiresolution analysis was proposed through the discrete wavelet transform for voltage analysis at the common coupling point between the generation system and the electric grid. The standard deviation and the variation of the details coefficients of the wavelet transform were used for the detection and classification of disturbances. In the application of the method, pure sine-wave voltages with different types of disturbances were considered: voltage sag, voltage sweel, interruption, oscillatory transients and noise. And three cases of dynamic island detection were simulated with a grid connected photovoltaic system. The results obtained are presented and discussed for validation of the wavelet transform application in the analysis of grid connected photovoltaic systems. / Este trabalho apresenta um estudo sobre a aplicação da transformada wavelet no monitoramento e análise da qualidade da energia elétrica e na detecção de ilhamento em sistemas de geração distribuída, abordando como estudo de caso um sistema fotovoltaico conectado à rede elétrica. Inicialmente é feita uma introdução sobre os sistemas de geração distribuída, as normas e requisitos para operação. Em seguida são apresentados os conceitos e parâmetros relativos à qualidade de energia elétrica e condições de ilhamento. Depois é mostrada uma revisão da transformada wavelet, apresentando o conceito de análise multirresolução e as principais aplicações no tema abordado. A transformada wavelet é uma importante contribuição para métodos de localização tempo-frequência na análise de sinais transitórios. Foi proposta uma análise multirresolução através da transformada wavelet discreta para análise da tensão no ponto de acoplamento comum entre o sistema de geração e a rede. O desvio padrão e a variação dos coeficientes de detalhes da transformada foram utilizados para a detecção e a classificação dos distúrbios. Na aplicação do método, foram consideradas tensões senoidais puras e com diferentes tipos de distúrbios: afundamento, elevação, interrupção, transitórios oscilatórios e ruídos. E foram simulados três casos de detecção de ilhamento dinâmica em um sistema fotovoltaico conectado à rede. Os resultados obtidos validam a proposta de aplicação da transformada wavelet na análise de sistemas fotovoltaicos conectados à rede.