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Published in Samuel C. Sugarman, HVAC Fundamentals, 2020
guy wire: (Definition) A tensioned cable designed to add stability to structures, as on an exhaust stack. One end of the cable is attached to the structure, and the other is anchored to the ground at a distance from the structure’s base. Aka guy-rope or guy.
Mechanical Design: Overhead
Published in Anthony J. Pansini, Electrical Distribution Engineering, 2020
Guy wire is made of stranded steel cable (usually 7 or 19 strands) so that the failure of one or two strands will not cause the immediate failure of the cable. The strands are usually galvanized or copper-clad to resist the effects of weather. The strands may be of mild steel or high-strength steel, but must be of sufficient strength to support the loads imposed on the guy. Such steel wires usually come in four grades of strength, and standards further specify that guy wires not be stressed beyond 75 percent of their ultimate strengths. Wires are manufactured in diameter differences or steps of n in, but sizes less than 1/32 in or greater than 1/4 in are seldom, if ever, used, two or more guys being employed if stresses greater than the maximum strength of the guy wire are required. In practice, however, only three sizes are usually stocked and specified: light, medium, and heavy; they are often referred to by their maximum permissible strengths, e.g., 6000-lb, 10,000-lb, and 20,000-lb (6M, 10M, and 20M).
Overhead Lines
Published in T. A. Short, Electric Power Distribution Handbook, 2018
Guy wires, messenger wires, and other wires that require mechanical strength but not current-carrying capability are often made of steel. Steel has high strength (see Table 2.5). Steel corrodes quickly, so most applications use galvanized steel to slow down the corrosion. Because steel is a magnetic material, steel conductors also suffer hysteresis losses. Steel conductors have much higher resistances than copper or aluminum. For some applications requiring strength and conductivity, steel wires coated with copper or aluminum are available. A copperweld conductor has copper-coated steel strands, and an alumoweld conductor has aluminum-coated steel strands. Both have better corrosion protection than galvanized steel.
Global status of wind power generation: theory, practice, and challenges
Published in International Journal of Green Energy, 2019
Muhammad Arshad, Brendan O’Kelly
Many small wind turbines are built with narrow pole/lattice towers supported by guy wires. The major advantage with such support structure is the cost-effectiveness due to lightweight fabrication. Whereas the disadvantages include a difficult access around the towers which make them less suitable in farm areas. Finally, this type of tower is more prone to destruction, thus conceding overall safety. Guyed lattice towers are constructed on the ground and raised with a crane or assembled vertically, one section at a time, with a process known as stacking. These towers are mostly used for turbines with rotor diameters less than 8 m. A concrete foundation is required for the base of the tower and also for the guy wire anchor points. Guyed towers have been used very infrequently and mainly for medium or larger size wind turbines having rated capacity of 1–2 MW.
Aerodynamic performance enhancement and computational methods for H-Darrieus vertical axis wind turbines: Review
Published in International Journal of Green Energy, 2022
Temesgen Abriham Miliket, Mesfin Belayneh Ageze, Muluken Temesgen Tigabu
Placing the H-Darrieus turbine in the convergent duct can increase the upstream wind speed near the blades (de Santoli et al. 2014). According to the CFD investigation carried out between 2 m/s and 12 m/s inlet wind speed, the result shows 32.2% and 30% wind speed enhancement respectively in the middle of the duct. Similarly, the power generated at 8 m/s and 15 m/s was maximized by 125% and 30%, respectively. The reason for low speed and power amplification at high wind speed was due to higher pressure loss at a corresponding flow. Placing a straight plate deflector upstream side of the H-Darrieus turbine enhances efficiency (Kim and Gharib 2014, 2013). This significantly increases the streamwise local wind velocity which leads to upgrade the angular speed of the rotor while the change of angle of attack was minimized from the no-deflector case. Providing flow augmentation devices such as duct, stator, diffuser, and guide vanes can increase the incoming wind speeds which significantly improve the performance of the turbine (Wong et al. 2017). Most of these devices are installed at the upwind side of the turbine and used as shields to reduce the negative torque created on the VAWT, guide the flow to a better angle of attack, increase the wind velocity towards the turbine blade. The blades are configured as cantilever support with or without guy wire at the top of the main tower, while the aerodynamic braking system is mounted near to the ground on the support bar (Tjiu et al. 2015b). Cyclonical surface wind lens configuration of S1046 airfoil blade with a diffuser significantly improves the performance of VAWT than traditional orientations (Hashem and Mohamed 2018).