| 摘要 |
PROBLEM TO BE SOLVED: To determine the existence of partial discharge by measuring both a magnetic field component generated by a high frequency current flowing through a ground wire and a magnetic field component propagated in a space from a partial discharge generation source. SOLUTION: First and second measurement sensors 11, 21 are arranged in the vicinity of the ground wire. A magnetic field A is generated in the ground wire by a pulse current 6, and a magnetic field B is generated inside a transformer, and propagated in a space. The first measurement sensor 11 measures the magnetic field A and the magnetic field B in the same direction, and the second measurement sensor 21 measures the magnetic field A and the magnetic field B in the opposite directions. Thus, the magnetic field captured by the first measurement sensor 11 becomes the magnetic field B+magnetic field A, and the magnetic field captured by the second measurement sensor 21 becomes the magnetic field B-magnetic field A. Next, the difference and the sum of both the magnetic fields are obtained, and the components of the magnetic field A and the components of the magnetic field B are extracted. The extracted magnetic field signals A, B are compared. If both the signals are equal to a threshold or more, it is counted as the partial discharge signals. If the count number is equal to a threshold or more, the existence of the partial discharge is determined. COPYRIGHT: (C)2010,JPO&INPIT
|
