|Budget Amount *help
¥8,900,000 (Direct Cost : ¥8,900,000)
Fiscal Year 2000 : ¥2,500,000 (Direct Cost : ¥2,500,000)
Fiscal Year 1999 : ¥2,900,000 (Direct Cost : ¥2,900,000)
Fiscal Year 1998 : ¥3,500,000 (Direct Cost : ¥3,500,000)
In this research, it inquired aiming at realization of telemetering of inside magnetic flux of electric power apparatus. Consequently, the composition technology of the telemetry system using laser and the synthetic technology of Faraday crystals were able to be developed.
As the first step, by measuring both of the transmittance and the Verdet constant, we established method of calculating its optimum thickness. According to this designing method, the measurement system to which telemetering of the high magnetic field inside a superconductivity magnet or the weak magnetic field of the circumference of a power line can be carried out was made as an experiment, and it has verified that measurement accuracy of the same grade was acquired as compared with the measurement result by the gauss meter which is the existing technology. Furthermore, the light CT which is with this measuring method and measures the current of a power line by laser was developed. Change of the circumference envir
onment which this light CT uses especially the temperature characteristic of laser and a crystal element, the laser incidence light characteristic of a crystal element, and the oscillation characteristic of light CT were measured, and the basic data for the practical use utilization was obtained. Furthermore, various failure examinations of short-circuiting 3 phases in the simulation power line of Kyushu Electric Power Co. using this light CT were carried out. Consequently, measurement by the large dynamic range from regular current to failure current was performed, and the good result was obtained. This optical CT measurement technology is applicable to telemetering of internal flux of electric power apparatus by replacing the crystal element.
As the second step, The Faraday crystal for feeble magnetic field measurement was compounded by the pulsed-laser deposition. Consequently, compared with the crystal put in practical use, the Verdet constant has compounded large Bi : YIG.A pulsed-laser deposition method has a complicated parameters called the distance between target-boards, oxygen pressure, and substrate temperature By this research, the generation conditions of Bi1Y2Fe5O12 thin film were able to be narrowed down by investigating these systematically and evaluating by XRD or SEM observation. The Verdet constant of the compound crystal thin film and the absorption coefficient were measured. Consequently, it turns out that crystallinity and composition of material have influenced laser wavelength and the Verdet constant. At last, the prospect of the optimum composition method of the Faraday crystal applied to the optical CT measuring method of power line current was acquired.