| Summary: | 碩士 === 國立臺灣科技大學 === 電機工程系 === 92 === This research is used to investigate the distribution of power-frequency magnetic fields in the primary distribution substations (D/S) and the reduction methods. It is required to handle the characteristics of power frequency magnetic field from substation equipments. The feasible methods must be evaluated for reducing the magnetic intensity in the area around substations and let substations be friendly to people. The magnetic measurement device, EMDEX II, will be used to measure the indoor and outdoor magnetic flux density distribution of substations, and the power loading of the substations must be recorded in order to estimate the maximum magnetic flux density in heavy loading conditions. The major and sub-major magnetic sources must be identified as the basic data for improvement methods. The FLUX 3D simulation tool will be used in the computer simulation. The cable arrangement, transformer, bus bar modes must be included. This research will consider two improvement ideas. (1) The magnetic field would be reduced in the source sides. It includes the cable arrangement and distance of cables from the fences. Three-phase magnetic flux values from currents should be cancelled by themselves as well as possible. (2) Some shielding materials could be used to shield the magnetic flux. The better places may be in the inner-wall of cable rooms, where there are many 22.8kV/11.4kV cables placed along the wall. This project hopes to find the characteristics of substation equipments on the distribution of magnetic field. The improvement and shielding methods should be a trade-off between economics and technology. It is appreciated that the magnetic flux density around a substation should be as low as possible to avoid any undesired problems.
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