| 摘要 |
PURPOSE:To measure the condition of deterioration in insulation by calculating it basing on a constant of the deterioration in the insulation in the form of direct connection from a DC insulation resistance R and an electrostatic capacitance C between an electric line and the ground and effective and dead components contained in the leakage current fed back with the application of a low frequency voltage between the electric line and the ground. CONSTITUTION:An insulation resistace R and a ground electrostatic capacity C exist in electric lines 3 and 4. When the electric lines have a deterioration in the direct connection of a resistance R1 and an electrostatic capacity C1, the value of the DC insulation resistance R can be measured by applying a DC voltage between points A and B. The ground electrostatic capacitance value C can be measured by connecting an AC bridge between points A and B to measure the electrostatic capacitance. An oscillator OSC oscillates a frequency f0 to apply an AC voltage of the frequency f0 to the electric lines 3 and 4 through a final terminal resistance r1. With the application of the AC voltage of the frequency f0, current flows by way of the insulation resistance R, the ground electrostatic capacitance C, the insulation deterioration resistance R1, the electrostatic capacitance C1 and the like. From outputs OUT1 and OUT2, effective components 1/kg and dead effect Cg contained in the leakage current, the insulation deterioration resistance R1 and the electrostatic capacitance C<1> are calculated and the consumption of current and power flowing therethrough is done in the live state of the electric lines 3 and 4. This allows the estimation of the heat generation to determine whether or not it is dangerous as insulation deterioration. |
