| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem, wherein when the electrostatic capacitance between a low-voltage electric line and the ground is present, whether normally an injection voltage to a class-B ground line is to be used as a reference voltage or the voltage of an electric line is to be used as the reference voltage, when testing the insulation state of low-voltage electric line, and then to enable measurement of the insulation state of the electric line using only the current flowing in the class-B ground line, independently of the reference voltage. SOLUTION: Fundamental wave, fifth-order harmonic wave, and seventh-order harmonic wave currents contained in the class-B ground line in a large number of fields are measured by dividing into power circuits and lamp circuits, and the relations between the currents and the insulation resistance values of electric lines are compiled to equations, based on actually measured data and the equations, are stored into a CPU built in a clamp type leakage current meter. Then, the insulation state of the electric line can be measured by only clamping to the class-B ground line. COPYRIGHT: (C)2005,JPO&NCIPI
|
