| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a grounding accident point survey device capable of shortening a survey time until specifying an underground accident point, as short as possible, and capable of surveying surely the accident point precisely from a ground surface by compact device configuration. <P>SOLUTION: The grounding accident point survey device includes a survey signal injection means 1 for injecting respectively two high-frequency waves of survey signals S1, S2 different in phases by 180° between underground buried cables (underground distribution cables) comprising two lines 201, 202 and the ground, a portable type magnetic field sensor 2 for detecting a magnetic field generated by the two high-frequency waves of survey signals S1, S2 propagated through the two lines 201, 202, and a control/display means 3 for inputting a feedback signal of the survey signal injection means 1 to control the survey signals S1, S2, and for displaying values thereof, the survey signals are thereby negated each other to provide no reaction in a receiver, as to an extended direction of the underground distribution cables in a sound circuit side from the injection point of the survey signals in the underground distribution cables, and a large detection level of prescribed amount is secured as to an extended direction of the underground distribution cables where the accident point exists. <P>COPYRIGHT: (C)2008,JPO&INPIT |
