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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Optimization of floating PV systems : Case study for a shrimp farm in Thailand

Louise, Wästhage January 2017 (has links)
The use of solar photovoltaic (PV) systems have expanded rapidly the last decade and today’s market includes several different solar utilizations, where floating PV is one of them. Previous studies have shown how floating PV systems increase the PV efficiency and at the same time reduce the water evaporation. The purpose of this study is to evaluate and optimize energy solutions using floating PV systems for a shrimp farm cultivation in Thailand, where the technical, environmental and economic aspects will be included. The optimizations have been done in the open source model OptiCE, where genetic algorithm (AG) have been used to maximize the renewable reliability and minimize the Levelized Costs of Electricity (LCOE). In order to find the optimal renewable solution for the investigated shrimp farm, four scenarios have been compared considering different PV system combinations. The simulated results showed how the scenarios considering floating PV system generated a higher reliability than the scenarios considering ground-mounted PV system. The scenario considered tracking PV system increased the system´s renewable reliability compared to fixed PV system. However the shrimp farm is connected to the national electric grid or not will have a huge impact on the LCOE due to the low electric price and the implemented feed-in-tariff (FIT) program. The size of the installed PV capacity significantly affects the reliability results were the capacity of 200 kWp reaches a reliability of almost 100%. The optimal solution for the investigated shrimp farm to become independent is therefore to install a combined floating PV and battery storage system.
22

Coordinated active power reduction strategy for voltage rise mitigation in LV distribution network

Ainah, Priye 16 August 2018 (has links)
Integration of renewable energy systems by the utility, customers, and the third party into the electric power system, most especially in the MV and LV distribution networks grew over the last decade due to the liberalization of the electricity market, rising energy demand, and increasing environmental concern. The distributed rooftop PV system contributes to relieve the overall load, reduce losses, avoid conventional generation upgrade, and better matching of demand on the LV distribution network. Originally, the LV distribution network is designed for unidirectional current flow, that is from the substation to customers. However, a high penetration of rooftop solar PVs (with power levels typically ranging from 1 – 10 kW) may lead to the current flowing in the reverse direction and this could result in a sudden voltage rise. These negative impacts on the network have discouraged the distribution network operators (DNOs) to allow increased PV penetration in the LV distribution network because some customers load, and equipment are sensitive to voltage perturbation. Presently, the most applied voltage rise mitigation strategy for high rooftop solar PV penetration is the total disconnect from the LV distribution network when the voltage at the point of common coupling (PCC) goes above statutory voltage limits. However, the sudden disconnection of the PV system from the grid can cause network perturbation and affect the security of the network. This action may also cause voltage instability in the network and can reduce the lifetime of grid equipment such as voltage regulators, air conditioner etc. Due to this negative impact, different voltage rise mitigation strategies such as the active transformer with on load tap changers (OLTC), distributed battery energy storage system and reactive power support (D-STATCOM, etc.) have been used to curtail voltage rise in the distribution network. However, the implementation of D-STATCOM device on a radial LV distribution network results in high line current and losses. This may be detrimental to the distribution network. Therefore, in this thesis, a coordinated active power reduction (CAPR) strategy is proposed using a modified PWM PI current control strategy to ramp down the output power and voltage of a grid-tied voltage source inverter (VSI). In the proposed strategy, a reactive reference is generated based on the measured voltage level at the PCC using a threshold voltage algorithm to regulate the amplitude of the modulating signal to increase the off time of the high frequency signal which shut down the PV array momentary in an extremely short time and allow the VSI to absorb some reactive power through the freewheeling diode and reduce voltage. The proposed CAPR strategy was designed and simulated on a scaled down simple radial LV distribution network in MATLAB®/Simulink® software environment. The results show that the CAPR can ramp down the PV output power, reduce reverse power flow and reduce the sudden voltage rise at the point of common coupling (PCC) within ±5% of the standard voltage limit. The study also compares the performance of the proposed CAPR strategy to that of the distributed static compensator (D-STATCOM) and battery energy storage system (BESS) with respect to response time to curtail sudden voltage rise, losses and reverse power flow. The investigation shows that the D-STATCOM has the faster response time to curtail voltage rise. However, the voltage rise reduction is accompanied by high current, losses and reverse active power flow. The introduction of the BESS demonstrates better performance than the D- STATCOM device in terms of reverse power flow and losses. The CAPR strategy performs better than both D-STATCOM and BESS in terms of line losses and reverse power flow reduction.
23

Optimal energy-efficiency retrofit and maintenance planning for existing buildings considering green building policy compliance

Fan, Yuling January 2017 (has links)
Reducing global energy consumption is a common challenge faced by the human race due to the energy shortage and growing energy demands. The building sector bears a large responsibility for the total energy consumption throughout the world. In particular, it was concluded that existing buildings, which are usually old and energy-inefficient, are the main reason for the high energy consumption of the building sector, in view of the low replacement rate (about 1%-3% per year) of existing buildings by new energy-efficient buildings. Therefore, improving the energy efficiency of existing buildings is a feasible and effective way to reduce energy consumption and mitigate the environmental impact of the building sector. The high energy intensity and requirements of a green building policy are the main motivation of this study, which focuses on finding cost-effective solutions to green building retrofit and maintenance planning to reduce energy consumption and ensure policy compliance. As about 50% of the total energy usage of a general building is caused by its envelope system, this study first proposes a multi-objective optimization approach for building envelope retrofit planning in Chapter 2. The purpose is to maximize the energy savings and economic benefits of an investment by improving the energy efficiency of existing buildings with the optimal retrofit plans obtained from the proposed approach. In the model formulation, important indicators for decision makers to evaluate an investment, including energy savings, net present value and the payback period, are taken into consideration. In addition, a photovoltaic (PV) power supply system is considered to reduce the energy demand of buildings because of the adequate solar resource in South Africa. The performance degradation of the PV system and corresponding maintenance cost are built into the optimization process for an accurate estimation of the energy savings and payback period of the investment so that decision makers are able to make informed decisions. The proposed model also gives decision makers a convenient way to interact with the optimization process to obtain a desired optimal retrofit plan according to their preferences over different objectives. In addition to the envelope system, the indoor systems of a general building also account for a large proportion of the total energy demand of a building. In the literature, research related to building retrofit planning methods aiming at saving energy examines either the indoor appliances or the envelope components. No study on systematic retrofit plan for the whole building, including both the envelope system and the indoor systems, has been reported so far. In addition, a systematic whole-building retrofit plan taking into account the green building policy, which in South Africa is the energy performance certificate (EPC) rating system, is urgently needed to help decision makers to ensure that the retrofit is financially beneficial and the resulting building complies with the green building policy requirements. This has not been investigated in the literature. Therefore, Chapter 4 of this thesis fills the above-mentioned gaps and presents a model that can determine an optimal retrofit plan for the whole building, considering both the envelope system and indoor systems, aiming at maximizing energy savings in the most cost-effective way and achieving a good rating from the EPC rating system to comply with the green building policy in South Africa. As reaching the best energy level from the EPC rating system for a building usually requires a high amount of investment, resulting in a long payback period, which is not attractive for decision makers in view of the vulnerable economic situation of South Africa, the proposed model treats the retrofit plan as a multi-year project, improving efficiency targets in consecutive years. That is to say, the model breaks down the once-off long-term project into smaller projects over multiple financial years with shorter payback periods. In that way, the financial concerns of the investors are alleviated. In addition, a tax incentive program to encourage energy saving investments in South Africa is considered in the optimization problem to explore the economic benefits of the retrofit projects fully. Considering both the envelope system and indoor systems, many systems and items that can be retrofitted and massive retrofit options available for them result in a large number of discrete decision variables for the optimization problem. The inherent non-linearity and multi-objective nature of the optimization problem and other factors such as the requirements of the EPC system make it difficult to solve the building retrofit problem. The complexity of the problem is further increased when the target buildings have many floors. In addition, there is a large number of parameters that need to be obtained in the building retrofit optimization problem. This requires a detailed energy audit of the buildings to be retrofitted, which is an expensive bottom-up modeling exercise. To address these challenges, two simplified methods to reduce the complexity of finding the optimal whole-building retrofit plans are proposed in Chapter 4. Lastly, an optimal maintenance planning strategy is presented in Chapter 5 to ensure the sustainability of the retrofit. It is natural that the performance of all the retrofitted items will degrade over time and consequently the energy savings achieved by the retrofit will diminish. The maintenance plan is therefore studied to restore the energy performance of the buildings after retrofit in a cost-effective way. Maintenance planning for the indoor systems is not considered in this study because it has been thoroughly investigated in the literature. In addition, a maintenance plan for the PV system involved in the retrofit of this study is investigated in Chapter 2. / Thesis (PhD)--University of Pretoria, 2017. / Electrical, Electronic and Computer Engineering / PhD / Unrestricted
24

Enhanced frequency regulation functionality of grid-connected PV system

Showers, Obu Samson January 2019 (has links)
Thesis (MEng (Electrical Engineering))--Cape Peninsula University of Technology, 2019 / Electric utilities are confronted with challenges like rising fuel costs, aging equipment, increasing energy demand, frequency regulation and the difficulty to integrate renewable energy resources into the grid. The presence of photovoltaic (PV) penetration on the utility grid is also increasing significantly in recent years. With the recent rise in PV penetration and the advancement of the global PV industry, there is an urgent and a necessary need to introduce features in PV systems that will make them respond smartly. However, much of these can be addressed without negatively affecting the total performance and power quality of the grid. Hence, engaging smart Grid technologies, and leveraging the benefits of the distributed nature of PV, new prospects to unearth value can be created. Through the implementation of progressive energy storage techniques, efficient two-way communications, a grid-tied PV system can create significant value, mostly through improved PV contribution in grid support functions like frequency regulation. An enhanced frequency regulation functioning scheme for a grid-connected photovoltaic (PV) system is modelled in MATLAB/Simulink software environment. The system is designed to operate in grid ancillary services precisely, frequency regulation function. The model consists of a Photovoltaic (PV) plant with a battery connected to the grid through a three-phase inverter. A bi-directional DC-DC converter between the grid and the battery system is included. The model has a battery storage system that provide steady and regular active/reactive powers available while the grid transmit specific amounts of power needed for a specific duration. According to the design, either the grid or the PV system depending on the dominant energy situation charges the battery. The battery is designed to discharge only when the grid demands energy from the PV and if the PV system fails to meet the demanded active power or reactive power. The PV system and the battery storage is integrated with the grid with the aid of dc-ac inverter in such a manner that bi-directional flow of active and reactive power is achieved. A 1 MW PV system is connected to the utility grid through a three-phase voltage source inverter system. The grid nominal frequency is set at 50 Hz under normal operation. However, the frequency decreased when the PV was not producing required power hence, the battery responded almost instantaneously and returned the frequency to the nominal frequency. The effectiveness of battery storage system for utility grid frequency regulation was substantiated from the simulation results attained.
25

Photovoltaic Power Plant Aging

Perez de Larraya Espinosa, Mikel January 2020 (has links)
One of the most pressing problems nowadays is climate change and global warming. As it name indicates, it is a problem that concerns the whole earth. There is no doubt that the main cause for this to happen is human, and very related to non-renewable carbon-based energy resources. However, technology has evolved, and some alternatives have appeared in the energy conversion sector. Nevertheless, they are relatively young yet. Since the growth in renewable energies technologies wind power and PV are the ones that have taken the lead. Wind power is a relatively mature technology and even if it still has challenges to overcome the horizon is clear. However, in the PV case the technology is more recent. Even if it is true that PV modules have been used in space applications for more than 60 years, large scale production has not begun until last 10 years. This leaves the uncertainty of how will PV plants and modules age. The author will try to analyse the aging of a specific 63 kWp PV plant located in the roof of a building in Gävle, monitoring production and ambient condition data, to estimate the degradation and the new nominal power of the plant. It has been found out that the degradation of the system is not considerable. PV modules and solar inverters were studied, and even if there are more elements in the system, those are the principal ones. PV modules suffered a degradation of less than 5%, while solar inverters’ efficiency dropped from 95,4% to around 93%.
26

ENERGIANALYS AV FASTIGHETEN ANDERSLUND 12 : Energieffektiviseringsmöjlighet med solceller

Andersson, Alexander, Lindström, FAHRIYE Cennet January 2021 (has links)
Today's society is dependent on energy and the increasing use of energy affects the environment in a negative way. In Sweden, homes and premises account for 39% of total energy use. Achieving national environmental quality goals requires a reduction in energy use and the energy saving potential in the real estate sector is large. Energy use in buildings can be reduced by carrying out certain energy efficiency measures. Kårhuset by Mälardalen University was built in 1997 and it is a gathering place for students. The building is located on the campus area in Västerås and includes an office, restaurant kitchen, dining room, pub and meeting rooms for line associations. In this work, an energy survey has been carried out by the property Anderslund 12 (Kårhuset) to find out the current energy use and investigate the energy saving potential in the building.  The work's literature study analyzes previous research and similar case studies. Thereafter, the building's energy use has been simulated by IDA ICE by creating a basic model in the software using data from various authorities and site visits. The results of the basic model were then compared with simulations of various energy efficiency measures to evaluate the energy saving potential. The measures examined are window replacement, additional insulation of exterior walls and replacement of heat exchangers in the air handling units. As a complementary alternative, energy efficiency with solar cells on the roof was investigated. The conclusion is that the property's energy use exceeds the average of Swedish premises' energy use. In connection with a possible renovation, the building has good opportunities for more efficient energy use. By carrying out all the measures that have been proposed, the heating demand can be reduced by 39% and the energy supplied can be reduced from 156.9 kWh / m2, Atemp, year to 103 kWh / m2, Atemp, year. Complementary installation of solar cells is a profitable alternative for reducing the building's extremely high electricity consumption.
27

Life Cycle Assessment (LCA) for a DC-microgrid energy system in Fjärås / Livscykelanalys för ett DC-mikronät energisystem i Fjärås

Hashemi Farzad, Tabassom January 2019 (has links)
Application of Photovoltaic PV panels for electricity production has rapidly increased in recent years in Sweden after launching a capital subsidy for PV panel installations in 2009. Kungsbacka municipality’s housing company equipped two groups of buildings in Fjärås with PV systems to generate electricity. The newly built residential buildings are connected to a DC-microgrid, whereas the existing buildings have been equipped with a single PV system. This project conducts a cradle to gate life cycle assessment (LCA) for this DC-microgrid energy system. The main purpose of this project is to determine which parts and processes of the DC-microgrid contribute to highest environmental impact throughout their lifespan from cradle to gate stages. Moreover, this study explores the energy payback time (EPBT) and the cumulative energy demand (CED) for the DC-microgrid. Additionally, this study performs two comparative LCA. First the DC-microgrid is being compared with PV system to determine which system has higher environment impacts, and secondly, the DC-microgrid is being compared with the average electricity mix in Sweden in terms of contribution to environmental impacts. The LCA follows the ISO 14040 framework and the baseline method is applied in order to assess 11 environmental impact categories. Two different functional units are adopted in this study. One is based on installed kilowatt peak (kWp) capacity by which environmental impacts of the PV system are compared with the DC-microgrid system. The other functional unit for this study is 1 kWh of delivered electricity to residential buildings produced by the DC-microgrid system. This functional unit is used exclusively for a stand-alone analysis of the DC-microgrid system in order to make it comparable with other microgrid systems or other systems with different energy sources, such as hydro, wind or nuclear. The results of the stand-alone LCA analysis of the DC-microgrid show that the battery has high contribution in human toxicity and terrestrial ecotoxicity whereas the energy hub system (Ehub) is the main contributor to eutrophication, abiotic depletion, fresh water aquatic ecotoxicity and marineaquatic ecotoxicity. The monocrystalline PV panel has the highest impact on global warming and abiotic depletion (fossil fuel). In addition, the EPBT for the DC-microgrid system is approximately 3.7 years. This means that one can get energy free of cost for an estimated time of 26.5 years if the lifetime of the system is assumed to be 30 years. The CED results show that monocrystalline PV production is an intense energy process which requires more non-renewable energy than all remaining parts of the DC-microgrid. The comparison of the DC-microgrid with the PV system reveals that the DC-microgrid has a higher environmental impact almost in all impact categories. This is mainly due to batteries and inverters which have a clear effect on the result. The CED analysis results illustrate that the multicrystalline PV panel production from the PV system is the most energy demanding process in both categories of renewable and non-renewable energy source. Moreover, the analysis illustrates that the DC-microgrid has still higher environmental impacts in all impact categories compared to the average electricity mix in Sweden. This is due to the electricity production in Sweden relies on hydropower and nuclear power with around 83 % of the total electricity production in the year 2017 which causes a lower environmental burden. Although the DC microgrid system shows a higher environmental impact compared to PV system, it is still a proper option to generate electricity since DC-microgrid system allows to achieve some indirect advantages such as energy saving due to an increase in own usage rate and self-sufficiency rate compared to the PV system. It should be noted that the end-of-life procedures becomes very important especially when crediting back for the recycling of materials. The collection and recycling of the PV panels at their end-of-life should be considered for future work as soon as reliable data are available. / Användningen av solpaneler har de senaste åren kommit att öka markant i Sverige. Ökningen beror på det statliga bidraget för installation av solceller som lanserades 2009. Kungsbacka kommun installerade solcellssystem i två olika typer av byggnader, ny och äldre befintlig byggnad. Den nya byggnaden anslöts till direkt mikronät (DC-mikcrogrid) och den äldre byggnaden utrustades med solcellssystem. Detta projekt utför en ’från vaggan till porten’ livscykelanalys (LCA) för energisystemet direkt mikronät. Syftet är i huvudsak att fastställa vilka delar och processer av det direkta mikronätet som bidrar till störst miljöpåverkan genom dess livslängd, det vill säga från vaggan till porten. Vidare undersöker studien återbetalningstiden (Energy PayBack Time, EPBT) och den ackumulerade energianvändningen (Cumulative Energy Demand, CED) för det direkta mikronätet. Studien utför två komparativa LCA varpå det direkta mikronätet först jämförs med solcellssystemet i syfte att fastställa vilket av systemen har större miljöpåverkan. Studien ämnar också jämföra det direkta mikronätet med den genomsnittliga energimixen i Sverige, också avseende miljöpåverkan. LCA metoden följer ISO 14040-ramverket. Studien är baserad på två funktionella enheter vilka består av installerad kilowatt peak (kWp) kapacitet vilken används för att jämföra solcellssystemet och det direkta mikromåttet. Den andra funktionella enheten är 1 kWh levererad elektricitet till bostäder som producerats genom det direkta mikronätet. Denna funktionella enhet används för en ’stand-alone’ analys av det direkta mikronätet i syfte att göra det jämförbart med andra mikrosystem eller system med olika energikällor så som vatten-, vind- och kärnkraft. Resultaten från ‘stand-alone’ livscykelanalysen av det direkta mikronätet visar på att batteriet har en större effekt på mänsklig toxicitet terrestrisk ekotoxicitet, varpå systemet för energihubb bidrar främst till övergödning, abiotisk utarmning, vattenlevande ekotoxicitet och havslevande ekotoxicitet. Monokristallin solpanel har större påverkan på global uppvärmning och övergödning (fossilabränslen). I övrigt är EPBT för det direkta mikronätet cirka 3,7 år vilket innebär att energin beräknas kostnadsfri i cirka 26,5 år, givet att det kan antas att systemets livslängd är 30 år. CED-resultat visar på att microkristallin solpanel är en intensiv energiprocess som kräver mer icke-förnybar energi jämfört med resterande delar av det direkta mikronätet. Jämförelsen mellan det direkta mikronätet och solcellssystemet visar på att det direkta mikronätet har större miljöpåverkan i de flesta kategorier. Detta beror i huvudsak på batterier och växelriktare som har tydlig effekt på resultatet. Av resultatet från CED-analysen framgår att produktion av multikristallin solpanel av solcellssystemet är det mest energikrävande processen i båda kategorierna för förnybar och icke-förnybar energikälla. Vidare framgår av analysen att det direkta mikronätet har en större miljöpåverkan i alla kategorier, jämfört med påverkan från genomsnittet av energimixen i Sverige. Detta beror på att elproduktionen i Sverige mestadels består av vatten- och kärnkraft som tillsammans 2017 utgjorde 83 procent av den totala energiproduktionen. Denna produktion orsakaren mindre miljöbelastning. Trots att det direkta mikronätet påvisar en högre miljöpåverkan än solcellssystemet, är det fortfarande ett alternativ till att generera elektricitet eftersom det direkta mikronätet bidrar till indirekta fördelar såsom energibesparing. Energibesparingen i det direkta mikronnätet sker således genom ökad användning av den egenproducerade energin samt självförsörjning. Det ska vidare tilläggas att ’end-of-life’ procedurerna blir viktiga i synnerhet när de återvunna materialet återanvänds. Vidare bör solpaneler återanvändas vid ’end-of-life’ vilket bör finnas i åtanke för vidarestudier och i samband med att data tillgängliggörs.
28

Investigation of Dual-Stage High Efficiency and Density Micro Inverter for Solar Application

Chen, Lin 01 January 2014 (has links)
Module integrated converters (MIC), also called micro inverter, in single phase have witnessed recent market success due to unique features (1) improved energy harvest, (2) improved system efficiency, (3) lower installation costs, (4) plug-N-play operation, (5) and enhanced flexibility and modularity. The MIC sector has grown from a niche market to mainstream, especially in the United States. Due to the fact that two-stage architecture is commonly used for single phase MIC application. A DC-DC stage with maximum power point tracking to boost the output voltage of the Photovoltaic (PV) panel is employed in the first stage, DC-AC stage is used for use to connect the grid or the residential application. As well known, the cost of MIC is key issue compared to convention PV system, such as the architecture: string inverter or central inverter. A high efficiency and density DC-DC converter is proposed and dedicated for MIC application. Assuming further expansion of the MIC market, this dissertation presents the micro-inverter concept incorporated in large size PV installations such as MW-class solar farms where a three phase AC connection is employed. A high efficiency three phase MIC with two-stage ZVS operation for grid tied photovoltaic system is proposed which will reduce cost per watt, improve reliability, and increase scalability of MW-class solar farms through the development of new solar farm system architectures. This dissertation presents modeling and triple-loop control for a high efficiency three-phase four-wire inverter for use in grid-connected two-stage micro inverter applications. An average signal model based on a synchronous rotation frame for a three-phase four-wire inverter has been developed. The inner current loop consists of a variable frequency bidirectional current mode (VFBCM) controller which regulates output filter inductor current thereby achieving ZVS, improved system response, and reduced grid current THD. Active damping of the LCL output filter using filter inductor current feedback is discussed along with small signal modeling of the proposed control method. Since the DC-link capacitor plays a critical role in two-stage micro inverter applications, a DC-link controller is implemented outside of the two current control loops to keep the bus voltage constant. In the end, simulation and experimental results from a 400 watt prototype are presented to verify the validity of the theoretical analysis.
29

A Real-time Management of Distribution Voltage Fluctuations due to High Solar Photovoltaic (PV) Penetrations

Ghosh, Shibani 24 January 2017 (has links)
Due to the rapid growth of grid-tied solar photovoltaic (PV) systems in the generation mix, the distribution grid will face complex operational challenges. High PV penetration can create overvoltages and voltage fluctuations in the network, which are major concerns for the grid operator. Traditional voltage control devices like switched capacitor banks or line voltage regulators can alleviate slow-moving fluctuations, but these devices need to operate more frequently than usual when PV generation fluctuates due to fast cloud movements. Such frequent operations will impact the life expectancy of these voltage control devices. Advanced PV inverter functionalities enable solar PV systems to provide reliable grid support through controlled real injection and/or reactive power compensation. This dissertation proposes a voltage regulation technique to mitigate probable impacts of high PV penetrations on the distribution voltage profile using smart inverter functionalities. A droop-based reactive power compensation method with active power curtailment is proposed, which uses the local voltage regulation at the inverter end. This technique is further augmented with very short-term PV generation forecasts. A hybrid forecasting algorithm is proposed here which is based on measurement-dependent dynamic modeling of PV systems using the Kalman Filter theory. Physical modeling of the PV system is utilized by this forecasting algorithm. Because of the rise in distributed PV systems, modeling of geographic dispersion is also addressed under PV system modeling. The proposed voltage regulation method is coordinated with existing voltage regulator operations to reduce required number of tap-change operations. Control settings of the voltage regulators are adjusted to achieve minimal number of tap-change operations within a predefined time window. Finally, integration of energy storage is studied to highlight the value of the proposed voltage regulation technique vis-à-vis increased solar energy use. / Ph. D.
30

Interface de supervisão para uma plataforma experimental de pesquisa e ensino em energia solar fotovoltaica

Hafemeister, Augusto 22 May 2018 (has links)
Submitted by JOSIANE SANTOS DE OLIVEIRA (josianeso) on 2018-11-13T12:55:39Z No. of bitstreams: 1 Augusto Hafemeister_.pdf: 17337125 bytes, checksum: bb32daa4e0367e3ae60ab686e81c9ef9 (MD5) / Made available in DSpace on 2018-11-13T12:55:39Z (GMT). No. of bitstreams: 1 Augusto Hafemeister_.pdf: 17337125 bytes, checksum: bb32daa4e0367e3ae60ab686e81c9ef9 (MD5) Previous issue date: 2018-05-22 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / CFC/CRCs - Conselho Federal de Contabilidade / PROSUP - Programa de Suporte à Pós-Gradução de Instituições de Ensino Particulares / O presente trabalho apresenta o desenvolvimento de uma interface de supervisão para integrar duas topologias diferentes de sistemas fotovoltaicos instalados na Unisinos, viabilizando estudos locais e a distância, ou seja, permitindo que alunos e pesquisadores de outras comunidades acadêmicas possam visualizar dados em tempo real e fazer intercâmbio de informações e discussões à cerca deste assunto. Para atingir as metas estabelecidas, o sistema foi desenvolvido sobre o software LabVIEW®, sendo as medições das grandezas elétricas e térmicas enviadas automaticamente para o Microsoft OneDrive®, o qual está em sincronismo com o site da Plataforma Experimental de Pesquisa e Ensino em ESFV. Além da integração dos sistemas mencionados, implementou-se um hardware para ajustar o ângulo de inclinação de um módulo fotovoltaico, agregou-se um traçador de curvas I-V e P-V, o qual permite fazer análises em condições reais de operação e também foram instalados dois sensores para medir a irradiância no plano do gerador fotovoltaico, ambos com monitoramento de temperatura e devidamente calibrados. Contudo, o principal diferencial dessa pesquisa está nos resultados encontrados na utilização da interface, em que foi possível comparar a performance dos módulos variando o ângulo de inclinação, correlacionando-o com a irradiância e a temperatura em diferentes dias típicos. Para um caso específico, foi analisado o comportamento da curva I-V durante um período de sombreamento, onde a eficiência de conversão atingiu menos de 6% e a potência máxima entregue foi 40% menor, mesmo estando coberta apenas uma das 60 células que compõem o módulo. Esse fato reforça a importância da análise experimental da curva característica para avaliação da qualidade e do desempenho do sistema, bem como identificar defeitos nas células e/ou no diodo de bypass. Por fim, simulou-se um modelo matemático, com base nas características do módulo fotovoltaico utilizado, a fim de avaliar os impactos da variação de temperatura e irradiância e também validar os resultados encontrados na prática. / This work presents the development of a supervision interface to integrate two different topologies of photovoltaic systems installed in Unisinos, making possible local and distance studies, allowing students and researchers from other academic communities to view real time data and to exchange information and discussions on this subject. To achieve the established goals, the system was developed over LabVIEW® software, with measurements of electrical and thermal values automatically sent to Microsoft OneDrive®, which is in synchronism with the Photovoltaic Teaching and Research Experimental Platform website. In addition to the integration of the mentioned systems, a hardware was implemented to adjust the angle of inclination of a PV module, an I-V and P-V curve plotter was added, which allows to perform analyzes under real operating conditions and also installed two sensors to measure the irradiance in the plane of the PV generator, both with temperature monitoring and properly calibrated. However, the main difference of this research is in the results found in the use of the interface, in which it was possible to compare the performance of the modules by varying the angle of inclination, correlating it with the irradiance and the temperature on different typical days. For a specific case, the behavior of the I-V curve was analyzed during a shading period, where the conversion efficiency reached less than 6% and the maximum delivered power was 40% lower, even cover only one of the 60 cells that make up the module. This fact reinforces the importance of the experimental analysis of the characteristic curve to evaluate the quality and performance of the system, as well as to identify defects in the cells and/or bypass diode. Finally, a mathematical model was simulated, based on the characteristics of the PV module used, in order to evaluate the impacts of temperature and irradiance variation and to validate the results found in practice.

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