Design of H-infinity Controller for Wind Turbine in the Cold Weather Conditions

Abstract. The periods with continuous freezing air temperatures reported during the spring of 2020 (13 incidents) affected a wide range of local and introduced sweet cherry cultivars in the region of Plovdiv. They vary from -0.6°C on March 02 to -4.9°C on March 16-17. The duration of influence of the lowest temperatures is 6 and 12 hours between March 16 and 17. The inspection of fruit buds and flowers was conducted twice (on March 26 and April 08) at different phenological stages after continuous waves of cold weather conditions alternated with high temperatures. During the phenological phase ‘bud burst’ (tight cluster or BBCH 55) some of the flowers in the buds did not develop further making the damage hardly detectable. The most damaged are hybrid El.28-21 (95.00%), ‘Van’ (91.89%) and ‘Bing’ (89.41%) and from the next group ‘Lapins’ (85.98%) and ‘Rosita’ (83.33%). A larger intermediate group form ‘Kossara’ (81.67%), ‘Rozalina’ (76.00%), ‘Sunburst’ (75.00%), ‘Bigarreau Burlat’ (69.11%) and ‘Kuklenska belitza’ (66.67%). Candidate-cultivar El.17-90 ‘Asparuh’ has the lowest frost damage values of 55.00% and El.17-37 ‘Tzvetina’ with damage of 50.60%.

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Heating up trickling filters to tackle cold weather conditions

Water Science & Technology ◽

10.2166/wst.2000.0025 ◽

2000 ◽

Vol 41 (1) ◽

pp. 163-166 ◽

Cited By ~ 3

Author(s):

W. Gebert ◽

P.A. Wilderer

Keyword(s):

Waste Heat ◽

Treatment Plant ◽

Weather Conditions ◽

Pilot Scale ◽

Cold Weather ◽

Filling Material ◽

Trickling Filter ◽

Biofilm Thickness ◽

Trickling Filters ◽

Biofilm Support

The investigated effects of heating the filling material in trickling filters were carried out at the Ingolstadt wastewater treatment plant, Germany. Two pilot scale trickling filters were set up. Heat exchanger pipings were embedded in the filter media of one of these trickling filters, and the temperature in the trickling filter was raised. The other trickling filter was operated under normal temperature conditions, and was used as a control. The results clearly demonstrate that the performance of trickling filters cannot be constantly improved by heating the biofilm support media. A sustained increase of the metabolic rates did not occur. The decrease of the solubility of oxgen in water and mass transfer limitations caused by an increase of the biofilm thickness are the main reasons for that. Thus, the heating of trickling filters (e.g. by waste heat utilization) in order to increase the capacity of trickling filters under cold weather conditions cannot be recommended.

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Rain Erosion Maps for Wind Turbines Based on Geographical Locations: A Case Study in Ireland and Britain

Journal of Bio- and Tribo-Corrosion ◽

10.1007/s40735-021-00472-0 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

K. Pugh ◽

M. M. Stack

Keyword(s):

Wind Turbine ◽

Western Europe ◽

Meteorological Data ◽

Turbine Blades ◽

Weather Conditions ◽

Annual Rainfall ◽

Wind Turbine Blades ◽

Weather Patterns ◽

The Uk

AbstractErosion rates of wind turbine blades are not constant, and they depend on many external factors including meteorological differences relating to global weather patterns. In order to track the degradation of the turbine blades, it is important to analyse the distribution and change in weather conditions across the country. This case study addresses rainfall in Western Europe using the UK and Ireland data to create a relationship between the erosion rate of wind turbine blades and rainfall for both countries. In order to match the appropriate erosion data to the meteorological data, 2 months of the annual rainfall were chosen, and the differences were analysed. The month of highest rain, January and month of least rain, May were selected for the study. The two variables were then combined with other data including hailstorm events and locations of wind turbine farms to create a general overview of erosion with relation to wind turbine blades.

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Cold weather is a predisposing factor for testicular torsion in a tropical country. A retrospective study

Sao Paulo Medical Journal ◽

10.1590/1516-3180.2013.7600007 ◽

2014 ◽

Vol 133 (3) ◽

pp. 187-190 ◽

Cited By ~ 3

Author(s):

Daniel de Oliveira Gomes ◽

Rafael Rocha Vidal ◽

Bruno Figueiredo Foeppel ◽

Danilo Fiorindo Faria ◽

Minori Saito

Keyword(s):

Retrospective Study ◽

Symptom Onset ◽

Testicular Torsion ◽

Weather Conditions ◽

Cold Weather ◽

Predisposing Factor ◽

Tropical Country ◽

Etiologic Role ◽

Urological Emergency

CONTEXT AND OBJECTIVE:Testicular torsion is a medical and urological emergency because it can lead to loss of the organ. The theory of seasonal testicular torsion occurrence is based on studies from institutions located in cold and temperate regions. The objective here was to determine whether cold weather is associated with higher incidence of testicular torsion in a tropical country, such as Brazil.DESIGN AND SETTING:Retrospective study, conducted in a tertiary and teaching hospital.METHODS:Patients with acute testicular torsion confirmed by surgery between April 2006 and March 2011 were studied. Information on weather conditions at the time of symptom onset was collected.RESULTS:A total of 64 testicular torsion cases were identified. The months with the highest incidences of testicular torsion were June (16%), July (19%) and August (11%), which had the lowest mean temperatures, of 17.6 °C, 16.4 °C and 18.2 °C, respectively. Eleven percent of cases occurred during spring (October to December), 16% occurred in summer (January to March), 34% occurred in fall (April to June) and 39% occurred in winter (July to September). There was a significant association between the incidence of testicular torsion and the season (fall and winter), P < 0.001.CONCLUSIONS:Testicular torsion follows a seasonal association even in a tropical country, and is more frequent in the colder months of the year, namely fall and winter, when almost three-quarters of the cases occurred. These observations add further evidence that cold weather has an etiologic role in testicular torsion occurrence.

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Abnormally High Power Output of Wind Turbine in Cold Weather: A Preliminary Study

International Journal of Rotating Machinery ◽

10.1155/s1023621x03000034 ◽

2003 ◽

Vol 9 (1) ◽

pp. 23-33 ◽

Cited By ~ 2

Author(s):

Christophe Leclerc ◽

Christian Masson

Keyword(s):

Wind Turbine ◽

Air Temperature ◽

High Power ◽

Power Output ◽

Cold Weather ◽

Air Density ◽

High Power Output ◽

Wind Velocities ◽

Preliminary Study ◽

Narrow Bands

According to popular belief, air temperature effects on wind turbine power output are produced solely by air density variations, and power is proportional to air density. However, some cases have been reported, all involving stall-controlled wind turbines, in which unexpected high power output was observed at very low temperatures.As a preliminary study, this article intends to quantify the influence of air temperature on the power production of the Tacke TW600 wind turbine installed in Tiverton, Ontario, Canada. Increases in power output due to air temperature variation are stratified by wind velocity, showing that these increases are below the theoretical limits of air density variations during operation in low winds and are comparable to and beyond those theoretical limits at higher wind velocities. At – 9°C and 0°C, narrow bands of power at distinct levels are observed in the stall regime of the turbine; they are typical of many stall phenomena observed on stall-controlled rotors, but these levels have been found to be independent of any parameters recorded.

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Ice fog monitoring near Fairbanks, AK

10.21079/11681/40019 ◽

2021 ◽

Author(s):

Dragos Vas ◽

Steven Peckham ◽

Carl Schmitt ◽

Martin Stuefer ◽

Ross Burgener ◽

...

Keyword(s):

Power Generation ◽

Environmental Conditions ◽

Weather Conditions ◽

Cold Weather ◽

The Arctic ◽

Local Power ◽

Environmental Complexity ◽

Ice Fog ◽

Innovative Methods ◽

Generation Facility

Ice fog events, which occur during the Arctic winter, result in greatly decreased visibility and can lead to an increase of ice on roadways, aircraft, and airfields. The Fairbanks area is known for ice fog conditions, and previous studies have shown these events to be associated with moisture released from local power generation. Despite the identified originating mechanism of ice fog, there remains a need to quantify the environmental conditions controlling its origination, intensity, and spatial extent. This investigation focused on developing innovative methods of identifying and characterizing the environmental conditions that lead to ice fog formation near Fort Wainwright, Alaska. Preliminary data collected from December 2019 to March 2020 suggest that ice fog events occurred with temperatures below −34°C, up to 74% of the time ice fog emanated from the power generation facility, and at least 95% of ice particles during ice fog events were solid droxtals with diameters ranging from 7 to 50 μm. This report documents the need for frequent and detailed observations of the meteorological conditions in combination with photographic and ice particle observations. Datasets from these observations capture the environmental complexity and the impacts from energy generation in extremely cold weather conditions.

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Corrective Solutions for the Shaft with Flange Used for Fixing the Blade on a 5 kW Wind Turbine to Withstand Extreme Weather Conditions

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1029.118 ◽

2014 ◽

Vol 1029 ◽

pp. 118-123

Author(s):

Rodica Bădărău ◽

Teodor Miloş ◽

Ilare Bordeaşu ◽

Adrian Bej

Keyword(s):

Mechanical Strength ◽

Wind Turbine ◽

Weather Conditions ◽

Extreme Weather ◽

Original Solution ◽

Root Area ◽

Materials Used ◽

Improved Design ◽

The Right ◽

Technical Solutions

The paper presents a case study on the original solution of a flange shaft as part of the root area of a 5 kW wind turbine blade. There were analyzed the causes that led to the shaft breakage under wind loadings in extreme weather conditions, and consequently technical solutions have been searched in order to improve the shaft design making it more reliable as mechanical strength at extreme wind loadings. The flange shaft is a welded subassembly that keeps the blades attached to the rotor hub. The first part of the paper consists in an analysis referring the loading status, the materials used for blade manufacturing, the identification of critical areas where the breaking was initiated and also the causes for which the materials assumed and specified in the technical design and manufacturing technology failed under loading at wind gusts of about 30 m/sec. Based on this preliminary analysis, the second part of the paper presents the technical solutions which were considered in reference to the materials and the improved design concept aiming to provide the right mechanical strength necessary to withstand specific wind loadings in extreme weather conditions.

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