Current Issue : July-September Volume : 2022 Issue Number : 3 Articles : 5 Articles
The reference evapotranspiration was calculated using Penman-Monteith method proposed. This method was evaluated on data measured by lysimeter in Szarvas experimental station in Hungary. The results of the two methods were in good agreement. However, this method requires an amount of data which is not available at all sites of meteorological measurement. Therefore it was necessary to investigate which elements influencing evapotranspiration are important and which elements are less important. With the help of investigation was indicated that radiation and vapor pressure deficit play important role in determination of reference evapotranspiration. Taking into account this there was two possibilities to calculate evapotranspiration. One of these is to use Penman-Monteith formula with constant wind speed as advised by Allen. Another one is to neglect wind speed data. Both methods were investigated and the method with constant wind speed was found better in a subhumid climatic condition of Hungary....
A simplified calculation method is proposed for determining the peak dynamic windage yaw angle (φ) of electricity transmission line (TL) tower suspension insulator strings (SISs). According to the rigid-body rule, the geometric stiffness matrix in the calculation of the windage yaw angle (φ) of SISs is dominated by the average wind loads, while the fluctuating wind loads are the dominant factor in the elastic stiffness. With the average wind state of conductors as the initial calculation condition, the loadresponse- correlation (LRC) method can be used to determine the fluctuating windage yaw angle (φd ) and the corresponding equivalent static wind loads (ESWLs). Then, the improved rigid straight rod model, which uses the actual length of conductors rather than the projected length, was used to determine the average windage yaw angle φ. Through the linear superposition of the horizontal increments of φ and φd (the peak value of φd ), the formulae to calculate the φ of SISs were derived. Additionally, the formulae for the dynamic wind load factor, βc, which is a key factor in designing wind loads for φ, were derived according to the principle of ESWLs, rather than being empirically determined by the Chinese code. Thus, the calculation model regarding the loads and response for the φ of SISs was established, and an actual TL was used to verify the established calculation model. Afterward, the influence of the different engineering design parameters on φ and its βc were analyzed. The parameter analyses show that the wind speed, span, and ground roughness influence the magnitudes of φ and βc, however, the height difference between the two suspension points of the conductors, the nominal height, and the sag-to-span ratio may be neglected in the approximate calculation. Our method offers a new solution to TL design when there are large deformations and small strains....
To reduce maintenance costs of wind turbines (WTs), WT health monitoring has attracted wide attention, and different methods have been proposed. However, most existing WT temperature monitoring methods ignore the fact that various wind conditions can directly affect internal temperature of WT, such as main bearing temperature. This paper analyzes the effects of wind conditions on WT temperature monitoring. To reduce these effects, this paper also proposes a novel WT temperature monitoring solution. Compared with existing solutions, the proposed solution has two advantages: (1) wind condition clustering (WCC) is applied and then a normal turbine behavior model is built for each wind condition; (2) extreme learning machine (ELM) is optimized by an improved genetic algorithm (IGA) to avoid local minimum due to the irregularity of wind condition change and the randomness of initial coefficients. Cases of real SCADA data validate the effectiveness and advantages of the proposed solution....
Since the 1970s, agricultural lands have served as useful locations for the installation of renewable energy generators, such as wind turbines, photovoltaic modules, biodigesters, and others. Likewise, agriculture is one of the five industries with the highest annual energy consumption in the US. Energy is a vital component in farms’ daily activities, which is involved in the harvesting of crops and the growth of livestock. Due to the current rapidly growing energy consumption trends, renewable energy sources have become a potential solution for energy generation. This paper focuses on the feasibility analysis of promoting the utilization of solar and wind energy generation to provide power for the operational activities involved in diverse agricultural processes through the performance of a geospatial analysis and an in-depth numerical analysis to study the patterns in the estimation of energy potential across the 254 counties located in the state of Texas. Furthermore, different patterns surrounding the thousand farms are analyzed, such as the distance to the largest cities and the location of heavily populated areas with higher energy potential. The results show that farms in several regions in Texas have significant potential to utilize wind and solar energy for their farm operations, and to supply electricity to the nearby population....
The subsea anchor piles of offshore wind power floating platform structures are mainly subjected to uplift and horizontal loads, and this paper focuses on the case of horizontal loads. A three-dimensional numerical simulation study of the horizontal pullout characteristics of wind power suction anchor piles in clay layers was carried out to reveal the horizontal movement state of the anchor piles during horizontal pile pullout, the range of pile depth at the pullout point where the horizontal movement is achieved (referred to as the horizontal movement range), the relationship between the pullout load and the ultimate load during the horizontal movement, and the optimal location of the pullout point for the horizontal movement. The results show that at certain pull-out points, the anchor pile produces an overall horizontal movement state under suitable horizontal pull-out loads. The depth of the pile pull-out point for horizontal movement is in the middle and lower part of the pile, i.e. 14.2 m to 14.5 m. The horizontal pull-out load of 24,000 kN at a depth of 14.5 m within the pile horizontal movement range of 14.2 m to 14.5 m is the maximum ultimate horizontal pull-out load; the optimum pull-out point depth is 14.5 m at 0.275 L (L is the pile length). For each pull-out point of the anchor pile in horizontal movement, the horizontal pull-out load in horizontal movement and the horizontal ultimate pull-out load existed and it was found that the two values were not exactly the same, the values were compared and it was found that at the optimum pull-out point the value of the ultimate horizontal pull-out load/horizontal pull-out load in horizontal movement tended to 1....
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