| 摘要 |
<P>PROBLEM TO BE SOLVED: To accurately detect a partial discharge without calibrating a magnetic field probe again once a calibration is performed. <P>SOLUTION: A pair of magnetic field probes 15a, 15b are disposed so as to be symmetric about a ground line 11 connected to a ground terminal of an electrical device 10. A calibration is performed by applying a calibration pulse to the ground line 11 without applying electricity to the device and summing outputs of a pair of the magnetic field probes 15a, 15b. At this time, an obtained calibration value is stored. Then, electricity is applied to the device and a partial discharge pulse is captured by a pair of the magnetic field probes 15a, 15b. Even though positions of the magnetic field probes 15a, 15b are comparatively changed, the sum of the outputs of the magnetic field probes does not change. Therefore, a charge amount can be calculated using the sum of the outputs. <P>COPYRIGHT: (C)2012,JPO&INPIT |
