Global ETD Search

1	Development of a model for estimation of wind farm production losses due to icing Hellström, Erik January 2013 (has links) Wind turbines operating in cold climate are exposed to periods of icing which lowers the plantprofitability by affecting the annual production. The loss of production has two components:The first (and most important) component is reduced power during operation due to disturbedaerodynamic properties of the blades. The second component is increased standstill. During this thesis project, methods to estimate production losses of a wind farm due to icinghave been developed, as well as a software tool to facilitate the use of these methods and thepresentation of the results. A method based on common metrological data and availableproduction data was desired, as modelling ice-related losses is expensive and may be inaccurate. The methods developed are based on using measured data for each turbine, such as activepower, temperature, wind direction and wind speed, and through this data describe theindividual turbine’s performance during different conditions. Production losses were thenestimated by comparing actual and expected power output (for the given wind speed). Thethesis then expanded on this basic concept by using reanalysis and mesoscale modelled data,which offers greater variety in the way estimating the losses may be performed, as well as theoption to derive losses for periods not covered by the production data. It was also important to develop a flexible and portable method that could incorporate newseasons of data or estimate losses for different wind farms with a completely differentconfiguration of turbines. The methods are developed using data from a wind farm in northern Sweden, consisting of 40Vestas V90 turbines and constructed a few years ago. It was found that eastern position in the wind farm and turbine altitude correlates with higherice-related losses, and that easterly winds relate to higher such losses than westerly winds. Thelosses during operation were estimated to 6.4 % of annual possible production and stops due toicing to 2.1 % of the total time. The losses figures are comparable to an earlier study performedin 2011 based on the same wind farm. The possibility of anti- or deicing systems for the wind farm and the profitability of such aninvestment should be further investigated as the wind farm is expected to continue operation fortwenty years or more. Wind power production losses ice losses estimation cold climate wind turbine
2	Wind Turbine Production losses in Cold Climate : case study of ten wind farms in Sweden Malmsten, Jon January 2011 (has links) As wind power expands rapidly worldwide, it is becoming more common to build wind farms in alpine locations where the wind resources often are good and conflicting interests are few. This is evident in Sweden where a substantial portion of the large wind parks planned are to be built in cold climate locations. The fact that icing of turbine blades and sensors can severely impact the production raises the question how large the losses are. In this thesis 10 wind parks comprising 45 turbines, well dispersed throughout Sweden are investigated. Daily production figures are compared to wind data from the MERRA reanalysis data-set in order to see if it is possible to determine the level of losses during the winter period caused by cold climate. A method is suggested where a relationship between daily production and daily average wind speed is established using representative summer days. This relationship is then used to calculate an expected production for the winter period. Losses are concluded as the difference between expected and actual production. The method did not produce a consistent and reliable result for the sites investigated. However, the method captures the overall trend with higher losses in the north of Sweden compared to the sites in the south where little or no icing is likely. At the sites where icing is expected, losses in the range of 10 to 20% of the annual production were calculated. Icing of wind turbines production losses cold climate reanalysis data Vindkraft Electric power engineering Elkraftteknik Mechanical and thermal engineering Mekanisk och termisk energiteknik
3	Možnosti uplatňování štíhlé výroby ve vybraném podniku / Possibilities of implementation the lean production in the choosen company MALATÍNOVÁ, Lenka January 2015 (has links) The aim of this thesis work is to evaluate the functioning of the already established elements of lean production, analyze production effectiveness before and after the introduction of these elements in the choosen company. This thesis characterizes the production before the introduction of lean production and shows deficiencies in the production process. These deficiencies have been eliminated implementation of lean production on the line. Subsequently indicators are evaluated before and after the introduction of the lean production. The experiment participants explains the principle of push and pull, one-piece-flow or customer tact.An integral part of the implementation of lean manufacturing was 5S method. It was proposed posible improvements for enterprise . It was recommended to conduct thorough supplier evaluation and subsequent communication with them. Other recommendations focused on Kaizen management, which is a system for proposals to improve employees.
4	Guidelines for successful implementation of total productive maintenance in a chemical plant / Jethro Padya Mahlangu Mahlangu, Jethro Padya January 2014 (has links) With the world economy becoming unpredictable, it has become a necessity for businesses to relook at the way they do business. The world has become competitive and companies that aim to become profitable have seen the need to find ways to improve efficiencies and increase productivity to stay relevant. There has been an adoption of strategies that are aimed at improving the efficiencies in companies such as Total Productive Maintenance (TPM). The strategy is aimed at improving equipment efficiencies and increase productivity through the transfer of certain skills from maintenance personnel to operators. The aim is that the operators perform some of the activities that the maintenance people used to do and they do the more complex tasks. By transferring these skills to operators there is constant cleaning, inspections and lubricating of equipment. This frees up time for maintenance people to do planning and other jobs that require time and higher skills levels. The implementation of these activities allows companies to tap into unused capacity that was always hidden by breakdowns and unplanned stops. The process however requires commitment from management and all stakeholders involved in the organisation. There are prescribed implementation processes that can be followed or companies can follow their own processes but the fundamentals of involving people from the onset must be followed. The involvement of stakeholders creates commitment at all levels and in order to sustain this initiative people must be committed to it. The inclusion of the activities transferred from maintenance people to operators, will reinforce the knowledge and habits required from operators and perhaps sustain the initiative. / MBA, North-West University, Potchefstroom Campus, 2015 Total Productive maintenance Overall equipment efficiency TPM Deployment Autonomous maintenance Plant maintenance Preventative maintenance Planned maintenance Quality maintenance Focused improvement Early equipment management Training and education Safety Health and Environment TPM in administration Zero defects Zero waste Zero downtime 5S Breakdown maintenance Preventative maintenance Corrective maintenance Maintenance prevention Downtime losses Speed losses Defect losses Quality defect losses Normal production loss Abnormal production losses Maintenance schedules Prescribed TPM deployment Equipment failure Function failure Function reduction Reprocessing losses Factors of successful TPM deployment
5	Guidelines for successful implementation of total productive maintenance in a chemical plant / Jethro Padya Mahlangu Mahlangu, Jethro Padya January 2014 (has links) With the world economy becoming unpredictable, it has become a necessity for businesses to relook at the way they do business. The world has become competitive and companies that aim to become profitable have seen the need to find ways to improve efficiencies and increase productivity to stay relevant. There has been an adoption of strategies that are aimed at improving the efficiencies in companies such as Total Productive Maintenance (TPM). The strategy is aimed at improving equipment efficiencies and increase productivity through the transfer of certain skills from maintenance personnel to operators. The aim is that the operators perform some of the activities that the maintenance people used to do and they do the more complex tasks. By transferring these skills to operators there is constant cleaning, inspections and lubricating of equipment. This frees up time for maintenance people to do planning and other jobs that require time and higher skills levels. The implementation of these activities allows companies to tap into unused capacity that was always hidden by breakdowns and unplanned stops. The process however requires commitment from management and all stakeholders involved in the organisation. There are prescribed implementation processes that can be followed or companies can follow their own processes but the fundamentals of involving people from the onset must be followed. The involvement of stakeholders creates commitment at all levels and in order to sustain this initiative people must be committed to it. The inclusion of the activities transferred from maintenance people to operators, will reinforce the knowledge and habits required from operators and perhaps sustain the initiative. / MBA, North-West University, Potchefstroom Campus, 2015 Total Productive maintenance Overall equipment efficiency TPM Deployment Autonomous maintenance Plant maintenance Preventative maintenance Planned maintenance Quality maintenance Focused improvement Early equipment management Training and education Safety Health and Environment TPM in administration Zero defects Zero waste Zero downtime 5S Breakdown maintenance Preventative maintenance Corrective maintenance Maintenance prevention Downtime losses Speed losses Defect losses Quality defect losses Normal production loss Abnormal production losses Maintenance schedules Prescribed TPM deployment Equipment failure Function failure Function reduction Reprocessing losses Factors of successful TPM deployment

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