Airflow Cooling Simulation and Analysis for Extra- high Voltage Cable in Underground Tunnel
| Autor: | Chin-Feng Chen, 陳慶豐 |
|---|---|
| Rok vydání: | 2005 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 93 Electricity supply has become a significant issue as the population and industries grow massively in metropolitan areas and industrial parks over the past decades. It also plays a greater role as for high-tech industries especially in the semiconductor and Electro-Optical fields. Traditionally, we have elevated and underground power lines to provide electricity. As the increases of the public and environmental awareness, more elevated power lines goes underground. However, underground power lines encountering unavoidably problems in cable capacities and stability with larger demand. Furthermore, during the underground tunnels constructions, it’s often the result in damaging other underground pipes, causing traffic jams and road repavement, which makes destructive conditions for road safety, cityscape and maintenance of power lines. Therefore, an underground utility tunnels shall provide a more efficient and long-lasting quality for metropolitan areas and industrial parks. As we know, the internal temperature of the underground utility tunnels shall not exceed 370C. This is an important factor to maintain the quality, efficiency and safety of the extra-high voltage power line. This research will analyzing a variety of methods for cooling extra-high voltage power lines in the underground utility tunnel. The purpose is seeking for a better air ventilation cooling method with low initial cost and high efficiency. Three major types of ventilation methods were studied and compared as following: Aspiration, Forced draft and Aspiration draft. Each method consist two ventilation shafts. If Aspiration is adopted, one shaft will be operated by mechanical (suction) ventilation and the other operated with natural ventilation. Forced draft is adopted, one shaft will be operated by mechanical (supply) ventilation, the other one operated by natural ventilation and Aspiration draft with two shafts, both operated by mechanical (supply/suction) ventilations. In this paper, FLOVENT（FLOVENT business software）was adopted to process the 3D computer simulation analysis and calculate temperature and speed field tests with the power line inside the underground tunnel. Three circuits were designed and based on the heat losses of 161kV. Results of experiments showed that under external temperature of 300C and 180C, Aspiration, Forced draft and Aspiration draft all successfully maintain the internal temperature below 370C within 1000 meters. Be more specific, when external temperature was below 300C, temperature in the tunnel was approximately at 35.4℃while external temperature was below 18℃, temperature in the tunnel could be kept at 23.3℃. General speaking, there aren’t much of differences between the three ventilation methods. In conclusion, Aspiration, Forced draft and Aspiration draft can be adapted by users on demand. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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