| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a lightning current measurement method, which can measure a lightning current at an arbitrary point without the need for manufacturing, carrying, and installing a device. <P>SOLUTION: A sample is prepared by collecting a soil around the buried grounding conductor, a soil around a building base body, which is a discharge route for discharge excessive current caused by lightning strike, or a part of the building base body. Subsequently, the natural remanent magnetization recorded in the sample is measured. A process for measuring the remanent magnetization after the alternating current demagnetization, as well as alternating current demagnetization to the sample, are performed while alternate demagnetization level are gradually changed. Thereafter, alternating current demagnetization to the sample is performed to such a level that the remanent magnetization in the sample is completed removed. A conductive line is arranged in a predetermined distance from the sample, and gradual application of the current to the conductive line provides the magnetic field generated at each current value to the sample so as to derive the relation between the current and the magnetization intensity remaining in the sample. Further, the magnetization intensity measured and calculated during the alternating current demagnetization is compared with the derived relation between the current and the magnetization intensity remaining in the sample, and thereby a value and a polarity of applied current near the sample are estimated. <P>COPYRIGHT: (C)2004,JPO&NCIPI</p> |
