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  • 1.
    Behnood, Aref
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Optimal Operation of Battery Energy Storage Systems in Radial Distribution Networks2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In recent years, power systems are facing with various challenges arising from the increased share of renewable energy systems. Among all sections of power systems, distribution grids are affected the most since the majority of renewable energy sources are connected to distribution grids.

    As the penetration of Variable Energy Sources increases in electric grids, energy storage systems have become more influential. In this context, this thesis presents a new algorithm for the optimal operation of Battery Energy Storage Systems in distribution grids. The proposed algorithm aims to define the optimal operation of Battery Energy Storage Systems considering the network topology, the output power of Variable Energy Sources and the electricity prices from the one-day ahead electric market as well as real time control of the batteries through smart appliances.

    In order to do this, firstly a comprehensive study on the existing Optimal Power Flow methods is carried out. Then, AR-OPF which is a novel Optimal Power Flow method for radial distribution systems is presented and the required mathematical constraints, equations and parameters of Battery Energy Storage Systems for modelling in distribution systems are described. Then, the problem formulation and the proposed algorithm are discussed in detail.

    Further to energy storage as the main function of Battery Energy Storage Systems, the impact of the proposed method on other functions of Battery Energy Storage Systems such as voltage control, grid support and loss reduction will be investigated. In order to do so, the proposed algorithm is applied to the IEEE 34 node test system as a case study. This will be carried out through defining several different scenarios. Finally, a sensitivity analysis is performed on the size of the existing batteries and the electricity price. The thesis will be concluded by the findings and possible future works.

  • 2.
    Daraiseh, Firas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Gotland as a microgrid -  Energy storage systems frequency response in grids with high level of renewable energy penetration2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The Swedish island of Gotland , situated about 100 km from mainland Sweden in the Baltic Sea, represents a power system with a high wind power penetration. The island is connected to the mainland Sweden exclusively via two HVDC cables that provide the only source of active power and frequency control. The two cables can operate in different configurations, i.e. import or export power from or to mainland. However, in order to ensure the N-1 criterion, one of the cables currently always must import power from the mainland. This means that the available power exporting capacity is limited to the rated power of one of the cables. Therefore, in the case of having a fault on the exporting HVDC cable during low load demand and high wind power production, the power system will suffer from high active power transients that will increase the frequency above the acceptable threshold. Consequently, the protection system will trip the over-frequency relays, triggering cascading outages on the island that might eventually lead to blackout if the problem is not addressed correctly. Thus, increasing the renewable energy production on Gotland is currently considered as a risk that will increase the probability of instable over-frequency contingencies. This has led the local grid operator to cap the installed wind power capacity to its current level. Therefore, the ability to preserve the stability of the power system during islanded operations until the HVDC cables fault is cleared or the emergency reserves are online is essential for the growth of installed wind power capacity.

    The main objective of the thesis is to examine the capability of a centralized energy storage along with or without wind curtailment. The ESS is tested for maintaining the frequency stability during the unintentional islanding through dynamic studies using the software PSS/E. The results show that an ESS prevents frequency instabilities and provide frequency response during HVDC cables fault albeit of the absence of any form of rotating inertia. The results show that for today’s 185 MW of installed wind power capacity, an energy storage of 50 MW power capacity will reduce over-frequency instabilities in the case of HVDC cables fault from 13% to 1%. The analysis finds that the power capacity of the energy storage depends on the exported power from the HVDC cables at the instant of fault, which eventually relates to the installed wind power capacity. finally, the study shows that using wind power curtailment will significantly decrease the energy capacity of the energy storage.

  • 3.
    Ekweoba, Chisom Miriam
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Power cables in battery electric vehicles used in underground mining: Analysis of electromagnetic dynamics in high-power cables and development of application-specific design strategies for reduction of EMI2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The electrification of the automotive industry is growing in popularity, considering the environmental impacts of the conventional diesel-powered automobile. However, from the electromagnetic compatibility (EMC) viewpoint, it is observed that the use of variable-frequency drives (VFD) and relatively high-power cables to propel electrical motors has led to a considerable rise in electromagnetic interference (EMI) within and outside the machine. EMI could come from the fast switching of the inverter, electromagnetic radiation from the high- power cables, common mode and differential mode currents as well as parasitic coupling of some of the components in the machine. The signals transmitted by near-by communication cables can be distorted as a result or, in the worst case, interference with the controller area network (CAN) bus of the machine.This thesis work aims to investigate different ways of mitigating EMI in battery-electric mine trucks used for underground mining. Having a three-phase system with power cables consisting of three conductors per phase per traction motor connecting the variable frequency drives (VFD) to the motors, the electromagnetic emission is significantly high because of the current level transmitted by the cables. This is in addition to the fast switching frequency of the inverter as the load/torque varies. Cable models are made using a finite element method (FEM) simulation tool, Ansys electronics desktop. The models are used to study how the cable shielding and material, arrangements and phase orientation can impact the radiated EMI within the machine. Experimental measurements are made in order to validate the models. Parasitic coupling between cables and components such as shield and protective earth conductors is considered to estimate the emitted magnetic fields. Results from one of the simulations show that a hybrid shield consisting of 50% Mu metal and 50% copper will give shield effectiveness up to 65% with reference to when an only copper shield is used. Mu-metal is the next most recommended shield because of the system low fundamental frequency. Steel shield gives as high as 20% better shielding than copper.Further simulations present the trefoil placement of the cable bundles, with the center bundle positioned upside-down compared to the two outer bundles, as a better option compared to when the cables within bundles are placed in a linear configuration, although the difference in the induces EMI is only approximately 5%.The major conditions for the above stated preferred arrangements include that bundles of cables within each bundle are tightly held together and the phase orientation is such that a cable is placed farthest away from the cable with the corresponding phase in the neighbouring bundle. Study on the effect of the connection of cable shield shows that common mode current is increased with the shield connected to ground through the body of the machine. This will give a considerable rise to both conducted and radiated EMI, but could help to reduce the risk of current flowing in uncontrolled parts of the machine.

  • 4. El Gohary, Fouad
    Microgrid Economics: Incentivizing Self-Consumption of Solar Electricity in a DC Microgrid2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 5.
    Ericsson, Emil
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Gregorson, Eric
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Quantitative Risk Assessment of Wave Energy Technology2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    European Commission (2011) aims to reduce the greenhouse gas emission sby 85-95% by 2050 in comparison to 1990’s levels. Wave energy could be an important step to archiving this goal. This report aims to develop a quantitative risk assessment for the Uppsala University's wave energy converter. Failure rates have been collected from various databases and reports and have been processed accordingly in order to implement them in the risk analysis. CAPEX, OPEX and possible downtime windows have been estimated. A fault tree analysis (FTA) has estimated the total unavailability, unreliability and downtime. Furthermore an economical assessment model using Monte Carlo and the unreliability data from the FTA has been developed, estimating the expected LCOE and OPEX/WEC for parks consisting of 20, 100, and 200 WECs (wave energy converters). The result show that the O-ring seal has the largest impact on both the unavailability, and the economy of the OPEX/WEC. Second biggest contributor is the translator bearing failure. The study also shows that the CAPEX cost has to be reduced to make the LCOE competitive in comparison to other renewable sources. A comparison between the system unavailability and unreliability has also been done in terms of different component parameters.

     

  • 6.
    Fachrizal, Reza Fachrizal
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Development of an Electricity Spot Market Model based on Aggregated Supply and Demand Functions for Future Solar and Wind Power Deployment2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This master thesis aims to develop an electricity spot market model for simulating hourly day-ahead market prices, and use it to study future deployment scenarios for solar and wind power as well as the potential of nuclear phase out in the Swedish and the whole Nordic and Baltic power systems.

    The share of intermittent renewable energy (IRE) in Swedish power system is increasing and this is expected to continue in the next decades. The share of wind power has rapidly increased from less than 1% in 2005 to more than 10% of the total generation in 2015. Even though solar power generation is currently still very low in Sweden, the Swedish Energy Agency has estimated that solar power can cover up to 10% of the electricity demand in 2040. With an increasing share of intermittent renewable energy and the potential of a nuclear phase out, the prices on the electricity spot market are likely to change in the future.

    In this thesis, statistical approaches are used to find the correlations of the existing market prices to several physical parameters such as temperature, hydro reservoir level, nuclear power generation, IRE, etc., and these are used to construct the proposed market model and to simulate the future scenarios.

    The results show that there is a strong dependency of the system price on the hydro reservoir level, as well as firm correlations between the system price with nuclear generation, temperature, electricity consumption and IRE. Using the model, it is possible to show that the substitution of nuclear power generation with realistic shares of wind and solar power will not lead to a fundamental change in the market. However, it will be a different case if the solar power share is higher. High solar penetration in the market makes the system prices much more dynamic both on an hourly and a seasonal basis.

  • 7.
    Felicetti, Roberto
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Field Current Control for the Damping of Rotor Oscillations and for the Alternative Start of Synchronous Machines: Further Innovative Applications of Field Current Active Control besides UMP-Compensation2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The possibility to save energy in synchronous machines operation by dismissing d-axis damping bars and surrogating them with active excitation current control in sectored field winding is proved. In particular a way to recover the energy of rotor oscillations during power regulation is shown by means of a studycase generator whereas a self-starting machine is analytically and numerically designed in view of its next construction and test. Principal design requirements and limits for both applications are presented and discussed.

  • 8.
    Ferdoush, Md Asif
    Scania CV AB.
    System Stability of the Overhead Power Supply System used in the Electric Road System2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis presents the stability analysis of an Electric Road System (ERS), which is often abbreviated as eHighway, used for the electrification of the hybrid vehicle. The overall system modelling of the ERS, starting from the sub-station to the critical part of the Scania hybrid truck is performed in the MATLAB Simulink environment. The ERS consists of an overhead catenary line (OCL), where vehicles are electrified by using a pantograph mounted over the vehicle. The stability analysis of the power supply of the overhead line is done by taking into account several aspects of the system. The simulation results are validated with the real test track measurements and the deviations are shown. The frequency response of the system is considered to measure the stability margin. The resonance conditions are clarified and essential variable choke is proposed to damp them out. Also the harmonic components injected from the vehicle side, that are in the closer range of the resonance, are figured out and filtered. When multiple vehicles are electrified from the same catenary line, then there are interferences in between the vehicles. These disturbances both to the vehicles and the overhead power supply system are presented in the time domain. Finally, the results are shown to demonstrate the effectiveness of the variable choke to increase the stability margin in the overhead supply system. In the frequency domain results, it has shown that the resonance is shifted out of the system operating frequency. In the time domain results, it has shown that the high amplitude of the current and voltage signals are sufficiently damped out by variable choke implementation.

  • 9.
    Hassan, Mohamed Elhafiz
    mohamed-ahmed@siemens.com.
    Power Plant Operation Optimization: Unit Commitment of Combined Cycle Power Plants Using Machine Learning and MILP2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In modern days electric power systems, the penetration of renewable resources and the introduction of free market principles have led to new challenges facing the power producers and regulators. Renewable production is intermittent which leads to fluctuations in the grid and requires more control for regulators, and the free market principle raises the challenge for power plant producers to operate their plants in the most profitable way given the fluctuating prices. Those problems are addressed in the literature as the Economic Dispatch, and they have been discussed from both regulator and producer view points. Combined Cycle Power plants have the privileges of being dispatchable very fast and with low cost which put them as a primary solution to power disturbance in grid, this fast dispatch-ability also allows them to exploit price changes very efficiently to maximize their profit, and this sheds the light on the importance of prices forecasting as an input for the profit optimization of power plants. In this project, an integrated solution is introduced to optimize the dispatch of combined cycle power plants that are bidding for electricity markets, the solution is composed of two models, the forecasting model and the optimization model. The forecasting model is flexible enough to forecast electricity and fuel prices for different markets and with different forecasting horizons. Machine learning algorithms were used to build and validate the model, and data from different countries were used to test the model. The optimization model incorporates the forecasting model outputs as inputs parameters, and uses other parameters and constraints from the operating conditions of the power plant as well as the market in which the plant is selling. The power plant in this mode is assumed to satisfy different demands, each of these demands have corresponding electricity price and cost of energy not served. The model decides which units to be dispatched at each time stamp to give out the maximum profit given all these constraints, it also decides whether to satisfy all the demands or not producing part of each of them.

  • 10.
    Henrik, Lindblom
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Design and construction of a voltage source converter for a laboratory setup2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The grid stability and reliability is facing new challenges as the emerging number of intermittent renewable sources connected to the grid is increasing. With the introduction of the insulated-gate bipolar transistor, the three-phase VSC has grown more popular and is used in many applications.

    In this thesis a two-Level Voltage Source Converter was designed and constructed with rated IGBT modules at 1200V and 150A. It focuses on the design, construction and control of said converter. The control is done through the LabVIEW FPGA module. Tests showed that the converter is working according to wanted specifications and can be used in a laboratory setup.

  • 11.
    Hudji, Muadh
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Analys av elnät för begränsning av reaktiv effekt2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Ystad Energy is responsible for the power grid in Ystad municipality. With increasing demand for electricity, society has become more vulnerable. Therefore, authorities and electricity suppliers always work to ensure safe and secure electricity supply. Variations in energy demand and climate change put the electrical system in a difficult situation regarding electricity supply safety.

    Ystad Energy has noted that the power grid has high values of reactive power over a part of year, which may affect the losses and system operating conditions in both local and regional networks. Therefore, this work focuses on performing reactive power analysis in the power cables located between the high voltage substations and the low voltage substations, i.e. in the 10.7 kV level of the distribution network.

    All overhead lines in Ystad municipality are already buried in the ground to reduce line faults in the system due to weather and other influences. The data collection from Ystad Energy shows that the reactive power input increases most during the summer. Underground cables are considered an important cause that contributes to reactive power input in an electrical system.

    Data collection also shows significant variations in energy consumption between the winter and summer months, where energy consumption is much lower in the summer due to the climate and human habits. Therefore, this leads to a voltage increase in the mains that can further lead to a capacitive reactive power generation.

    In the project, an analysis of the power grid has been performed, considering the current grid topology. Simulations of different scenarios with production plants, such as wind power, which can affect the power flow in the network, are also carried out.

    It was proved that the reactive power in the grid is produced by the underground cables. The report also presents some possible solutions that may be appropriate to reduce the reactive power in the network.

  • 12.
    Ibrayeva, Anar
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. ABB AB.
    Aspects of modelling and control of MMC based HVDC system2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Close location of high voltage direct current (HVDC) power transmission lines to high voltage alternating current (HVAC) transmission lines can induce the fundamental frequency AC voltage in HVDC line. For instance, it could happen if both AC and DC lines' conductors are placed on the same power towers.

    This induced voltage can cause a DC component of the current on the AC side of the converter if no additional measures or further action to reduce it is taken by the control of the converter. Presence of the DC offset can result in transformer saturation which may cause overheating, efficiency reduction, a shortened lifespan of the devices, voltage harmonics of the secondary winding output [1].

    This thesis work shortly explains the physics of the induced voltage in an HVDC transmission line placed close to HVAC line, describes the simulation model of the symmetrical half-bridge (See Figure 2.3) modular multilevel (HB MMC) HVDC system that is used for further analysis, determines the impact of control system of the converter to the DC component of the output current, explains an analytical method of calculation of the DC component of the output current of the HB MMC HVDC converter, compares the results of simulation with theoretically calculated value,explains their difference, and explains possible ways to overcome this problem.

    There are different approaches of analysis of dynamics of MMC HVDC converter. Some of them consider the replacement of submodules of the converter with an ideal voltage source, another calculates the ripple of the sum of arm capacitors, a third approach calculates ripple of each capacitor of the converter [2, 3, 4, 5].

    In this thesis the dynamics of the sum of arm capacitors is presented. The methodology is based on the research paper [6] and book [7] of Lennart Harnefors.

    PSCAD/EMTDC simulation software and the CIGRE B4.57 generic model of HVDC system were used for the verification of the described in this thesis methodology. The CIGRE model as well as model description can be found in open access on their website.

    All parameters' values for calculation of the output current DC component were taken from modelling output and compared with the simulation results from the model. According to the simulation results the maximum difference between measured and calculated DC offset reaches 13.7 %.

    Suggestions for the development of HB MMC HVDC converter control are made based on the calculation results.

  • 13.
    Lopez Gomez Partida, Fausto
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Design of a Permanent Magnet Synchronous Generator with Alnico Magnets2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Following the trends to diminish the fossil fuel energy production new technologies known for their renewable sources have become a signficant option for helping combat climate change and handle the current oil prices. These new technologies base their power production on already established physical principles that convert mechanical power to electrical power.

    Generators are the fundamental piece of machinery for electricity production. Among the various types of generators that exist, permanent magnet synchronous generators (PMSGs) are commonly used for renewable electricity production. At present, the most used magnets for PMSGs are alloys of neodymium, iron, and boron which form a tetragonal crystalline structure known as Neodymium magnets (NdFeB). These types of magnets contain rare-earth materials, which makes them highly non-sustainable materials. Research to find new magnet compositions to substitute rare earth magnets or to reduce the weight and increase the efficiency of PMSGs is currently being studied. One option is to use Alnico magnets. This thesis project explores this option.

    With the help of a finite element analysis (FEA) software (COMSOL Multiphysics), three types of Alnico grades 5, 8 and 9 were implemented in the rotor of a spoke type generator to study the load limits of the rotor magnets, and together with this observe the demagnetization and impact that it has on the power production of the generator, in two different scenarios: 1) When the generator is connected to a nominal load under normal conditions and 2) when the generator is connected to a nominal load after a short circuit (SC).

    The simulations provided an insight into the load limitations that the generator has by each type of Alnico studied. Alnico 9 showed to be the best candidate magnet from the three magnets implemented with less demagnetization and higher electrical power output, followed by Alnico 8, which presented a good electrical power output at the nominal load scenario. Regardless of the higher demagnetization of Alnico 5, it proved to be a better candidate than Alnico 8 at the SC scenario.

  • 14.
    Overmaat, Eduard
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Balancing Contributions in the Nordic Electricity System: Who bears the brunt of electricity production and consumption patterns?2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The share of intermittent weather-based renewable electricity sources has risen and will keep on rising in the Nordic electricity system, which will increase the need of balancing power in the Nordics. The previously developed concept of balancing contributions is used to look at the historic contribution of different power sources to the balancing on the grid. Three different time scales are taken into account: Daily variations, (bi-)weekly variations, and seasonal/yearly variations. This will aid in the understanding of the synergy of different sources on the grid, which, together with a deeper knowledge of the electricity market, might make it possible in the future to quantify the potential for balancing of sources within the Nordic grid.

    As a method to analyse the balancing contributions, a previously set-up online visualisation tool was used as an example, and this existing tool was revamped with a new software back-end using a database and automatic data collection. This allows one to be able to use a larger dataset, and for more functionality in the future, such as real-time updates and easier implementation of additional visualisations. Production and consumption data was gathered from Entso-e and SvK: the former has issues with data quality and the latter publishes data with a three-week delay which can only be obtained manually.

    The results from the previous research have been replicated, and a bigger dataset has been used to do the calculations, encompassing the years 2015-2018. The overall results show great similarity to that of the previous work. For the first time it was possible to plot the intrayear balancing contributions as a time series, which showed especially that the contributions of hydro power and electricity trade have changed over the period 2015-2018. There is a difference in hydro power balancing contributions based on geographical location, where Finnish hydro power is mainly a daily and—to a lesser extent—weekly regulator, Swedish hydro and especially Norwegian hydro have larger contributions on a yearly basis as well. There are even differences within countries, as the balancing contribution of hydro in bidding area SE2 has changed much more over time than hydro in SE1, for example. Other examples of interesting situations on the grid have also been highlighted using the online visualisation tool.

  • 15.
    Salar, Dana
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Miniature Wave Energy Converter (WEC)2018Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Abstract

     

     

    In this project, I present a design of a scale model of a linear generator (LG) similar to a full size Wave Energy Converter (WEC) being developed at Uppsala University since 2002 and commercialized by Seabased AB. The purpose of a WEC is to convert the energy from ocean waves into electrical energy.

    In order to implement the behaviour of the prototype design, a preliminary study has been done to further build it for use in education, laboratory tests and research. The challenge with this project is to scale down the WEC but maintain the shape, appearance and characteristics of the generator for educational purposes.

    A miniature version of a WEC, previously developed by Uppsala University in collaboration with Seabased Industry AB, has been designed with scaling rate 1:14 of the linear dimensions. In this case, the value of the output power is not important- it has simply been calculated. The electrical rated parameters of the three phase generator are power  26 W,  peak line-line voltage  13 V and  rated armature current  2 A. The mechanical parameters utilized in the design are the total length and the diameter of the miniature WEC, 50 cm and 25 cm, respectively.

    The simulated prototype model (described in Section 5.4) has been validated with an experimental setup comprising translator and stator (described in Section 5.1), where the translator is moved by a programmed industrial robot. The experimental results have shown good agreement with the simulations.

  • 16. Shahroozi, Zahra
    Force Prediction and Estimation for Point Absorber Wave Energy Converter2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 17.
    Sudhakaran, Sujith
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Impact of Renewable Energy Installations and Utilisation of Smart Energy Management Systems on low-voltage networks- a study case at Östergarnslandet, Gotland2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis carries out an analysis of PV panel installations in the region of Östergarnslandet, situated in the Swedish island of Gotland. A low-voltage grid of 0.4 kV in the region is examined with the help of software Open DSS. This is done with the data provided by the distribution grid owner, Gotlands Elnät AB (GEAB). The potential impacts created by the PV installations in terms of exceeding currents, voltages and harmonics are assessed and thereby the hosting capacity of Solar PV in the houses and on the whole grid is studied.

     

    Moreover, a theoretical review of the Smart Energy Management System (SEMS) is investigated about the performance and the devices involved in the system. Also, a battery which is a part of SEMS is modelled, taking into account the production and consumption of a single household connected in the grid. The battery sizes for various PV installations at the home is suggested via NPV analysis with the intention to increase the self-consumption and to reduce the cost of the electricity bill.

    In addition, a survey is conducted in the region with support from the Department of Earth Sciences, Uppsala University Campus Gotland. The survey is made to determine the attitude of the people in Östergarnslandet towards an energy transition.

    The results show that the maximum amount that can be installed or the hosting capacity of solar in the studied grid is 120 kW. From the simulations, it shows that the impacts created by these PV installations do not violate the specified Grid norms.

    From the theoretical analysis, SEMS is found to be a better solution for energy management at homes. The performance study done shows that 33 % of the solar energy produced in the home is directly used at the time of production. The remaining energy is used for battery charging for the future supply of power and feeding to the grid. The battery modelled for 10- kW PV installation in the home is found to be 9-kWh and the same for a 15-kW installation. Meanwhile, for a 20- kW installation, a 15-kWh battery is found to be ideal from the study.

    The survey conducted in the region has turned out to be positive as people are supportive of the energy transition. The responders have marked photovoltaics as the prime option for investment in energy production which assures that it has a good future in the area.

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