| 摘要 |
<P>PROBLEM TO BE SOLVED: To achieve accurate detection and calculation of an electric charge of partial discharge merely by calibrating a magnetic field probe once. <P>SOLUTION: Without supplying power to a main body of an electrical device, a calibrator is connected thereto and a calibration pulse and current noise from a rectifier or the like are passed. Then, a magnetic field probe 15 detects a magnetic field signal due to the calibration pulse and the current noise. After passing through LPF 18L and HPF 18H, the signal is fed to a signal processing unit 19, where the signal is processed and an electric charge of the noise is found and stored in a storage unit 20. Next, supplying power to the main body of the electrical device, the magnetic field probe 15 detects a magnetic field signal due to a partial discharge pulse and current noise. After passing through LPF 18L and HPF 18H, the magnetic field signal is sent to the signal processing unit 19 and an electric charge of partial discharge is found. Even when the magnetic field probe 15 is at a position different from where calibration is performed, by finding a noise intensity, an electric charge of partial discharge can be calculated without performing calibration of the magnetic field probe 15 again. <P>COPYRIGHT: (C)2012,JPO&INPIT |
