Figure 18.17. Vertical motion of structure restricted Can be used in very deep waters upto 2000m depth 28. Tension-leg platforms . A Tension Leg Platform (TLP) consists of a structure held in place by vertical tendons connected to the sea floor by pile-secured templates. Guyed towers are characterized by a clear transfer path of stress and reasonable structure. Due to this the platform experiences more horizontal motion due to the jerks from the rough weather. A guyed tower consumes less steel but occupies a large area. Carter Wind Systems [4, 5] used this technique to install several hundred 25 kW wind turbines in the 1980s using 18 and 25 meter (54 and 82 feet) towers (Figure 4.7). Sliding tension leg tower with pile base ... Abstract: A compliant offshore drilling and producing structure is disclosed. Because guyed towers need guy wires, they are usable only in plains areas or hilly areas. Remotely operated sea floor production systems have been designed for very deep waters (beyond 600 meters). The rig consists of narrow, flexible (compliant) towers and a piled foundation supporting a conventional deck for drilling and production operations. Lattice towers are not designed to withstand side-lifting loads as well as monopoles. Figure 8.4. In 1150-kV single-circuit transmission lines constructed by the former Soviet Union, the cost of towers and foundations accounted for 31% of the total construction cost, and steel consumed by towers for each kilometer of lines was 68. 1 Common Compliant Platforms 1. Compliant structure concepts may be classified in one of four categories: Articulated towers . However, unlikely jacket plkatforms, a compliant tower is designed to flex with the forces of waves, wind and currents . 1.5 Response Control Strategies 24. For this reason, guyed towers are not recommended. The structure is held in a fixed position by tensioned tendons, which provide for use of the TLP in a broad water depth range up to about 2000 m. Tension-leg platform is similar to these topics: Compliant Tower, Floating production storage and offloading, Fixed platform and more. Compared with floating systems, such as tension-leg platforms and SPARs, the production risers are conventional and are subjected to less structural demands and flexing. 1.5.2 Semi-Active Control Algorithm 25. 9 tons. Guyed towers can be adapted for erection using a tilt-up system. Taking into account the characteristics of ± 800-kV UHVDC lines in China, on one hand, because the towers are higher than ± 500-kV towers, excessively long guys are required (a single guy is usually as long as about 100 m), which is unfavorable for the tightening of guys; on the other hand, due to the larger height of these towers, guys are susceptible to becoming loose due to wind and ice loads, making operation and maintenance more difficult; moreover, as ±800-kV lines are generally subjected to much larger loads than ±500-kV lines, the guys are heavily stressed so that special types of guys and connections are required. Tension . Guyed towers . Remotely operated sea floor production systems have been designed for very deep waters (beyond 600 meters). Those towers are all lighter, with a weight in the range of 17–25 tons, but have a larger footprint. Natural periods are usually greater than 25 sec so they are generally well outside wave periods. Zhenya Liu, in Ultra-High Voltage Ac/dc Grids, 2015. … Such plants will be dependent for their operation on a broad agreement to, and application of, the Law of the Sea Convention. Figure 7.18. Crude oil and natural gas are moved up the articulated tower and transferred to the tethered tanker for processing and storage. The Base Tower makes up the first 250 metres of the more than 400 metre high tower. Guyed-tower platform and tension-leg platform. Fig. A smaller guyed lattice tower can also be assembled by adding a tower section one at a time using a clamp-on lifting pulley. FIXED- Fixed Leg Platform (see below for full description) FPSO- Floating production, storage, and offloading. James G. Speight, in Subsea and Deepwater Oil and Gas Science and Technology, 2015. The tension–leg concept calls for a floating platform permanently anchored to the seafloor by steel cables under tension. It is one of the world's tallest structures. A shuttle tanker is brought alongside to receive the processed crude oil and transport it to shore by means of a shuttle tanker or an export oil pipeline. Compared with floating systems, such as Tension-leg platforms and SPARs, the production risers are conventional and are subjected to less structural demands and flexing. Figure 7.20. Tension-leg platform. A 1000-kV double-circuit steel tubular angle tower in Japan. Compliant towers are designed to sustain significant lateral deflections and forces, and are typically used in water depths ranging from 1,500 to 3,000 ft. 3. 7.19 shows a 1110-kV suspension cable guyed tower designed by the Department of Energy of the United States. Single-circuit suspension self-supporting towers are mostly two types: cup-type or cat-head. Process design, power generation/distribution, control systems, piping, and installed equipment more or less follow the same concepts as explained in this book. The tension leg platform (TLP) can be economically competitive with the compliant tower for water depths between 300 and 1200 m. In this structure [ Fig. Exxon is further researching use of this type of platform in water depths to 5,000 feet. 1.5.1 Active Control Algorithm 25. tension leg platforms), but compliant towers still demonstrate static stability albeit with greater degrees of lateral deformation (up to 2.5%) compared to land-based structures (usually 0.5% or less). A self-supporting tower has a smaller footprint and is adapted to a variety of landforms. 15 - Wood Group Mustang Deepwater Systems Global Distribution . But they use narrower towers of concrete and steel. Tension leg platforms installed as of 2002 . Compliant towers are designed to sustain significant lateral deflections and forces, and are typically used in water depths ranging from 1,500 to 3,000 feet (450 to 900 m). The crane vessel that is partly visible is the Thialf. 7.17 shows a 1150-kV Y-shaped guyed tower designed in the former Soviet Union (Fig. #1 and #2 are conventional fixed Abundant experience with this tower type has been accumulated. Other types of platforms like guyed towers, tension legs, semisubmersibles, floating structures, etc. Tower types commonly used in UHVDC transmission lines: (A) Guyed tower; (B) self-supporting suspension tower (I-string); (C) self-supporting suspension tower (V-string); (D) suspension angle tower; (E) “” type tension tower. . The SALM system uses a yoke structure, buoyancy tank, and tensioned riser. It is one of the world's tallest structures. energy. 7.24 shows a 1100-kV self-supporting cat-head tower with three-phase conductors in triangular configuration, which is designed by BPA of the United States. Tower history The compliant tower concept has essentially progressed through an evolution of three configurations. Compliant Tower A compliant tower is a flexible structure with flex elements (principally flexible legs or axial tubes) to control mass and stiffness characteristics so as to mitigate the effects of periodic wind, wave and current forces. Figure 7.19. In deep water, most companies use compliant platform, which contain fewer steel parts and are lighter than rigid steel- jacket. 1030: Static fire success for Starship 9. 18.17) in terms of supporting means. Figure 7.22. This is the heaviest compliant tower installed to date and the first outside of the Gulf of Mexico. A self-supporting cup tower. Compliant towers are designed to sustain significant lateral deflections and forces, and are typically used in water depths ranging from 1,500 to 3,000 feet (450 to 900 m). Figure 8.6. However, it has advantages of narrower right-of-way and uniform power-frequency field strength along the right-of-way. 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