| 摘要 |
PURPOSE:To diagnose an insulating state in a charged state by calculating each insulation resistance value of the primary side and the secondary side of a transformer, respectively, based on a detection result of a leakage current detecting device interposed between a neutral point of the primary side of the transformer and the ground of the time when a DC voltage has been applied, and comparing a difference of both of them with a prescribed reference value. CONSTITUTION:Between a primary side winding neutral point of primary and secondary side ground use meter transformers 6, 11 and the ground, leakage current detecting devices 7, 11 of the primary side and the secondary side are interposed. The device 7 connects in parallel a series circuit of a switch 15, a capacitor C1, a coil L1 and a resistance r1, respectively, and applies a voltage generated in the resistance r1 to an arithmetic unit 14. The device 12 also connects a switch 16, a capacitor C2, a coil L2 and a resistance r2 in the same way, and applies a voltage generated in the resistance r2 to the unit 14. The unit 14 calculates primary and secondary side insulation resistances based on output voltages of the devices 7, 12, and also calculates a difference of both of them. Based on this difference, an insulating state can be discriminated.
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