| 摘要 |
PURPOSE:To detect the change or disconnection of the earth resistor of an auxiliary earth electrode, by measuring the current flowing through a tower- footing and the voltage of the tower-footing by a surge impedance meter to store the same in the first and second memories and calculating impedance from the data from both memories by the divider of said meter. CONSTITUTION:A pulse generator 9 applies pulse voltage to the tower-footing 1 of the iron tower of a transmission line at a position above the node of an auxiliary earth electrode 7. A toroidal coil 2 is wound around the tower-footing 1 between the pulse voltage applying point of the tower-footing and the node of the electrode 7. Further, a surge impedance meter 20 measures the current flowing through the tower-footing 1 by the output of the coil 2 to store the output thereof in the first memory and measures the voltage of the tower-footing to store the output thereof in the second memory. Impedance is calculated from the data from the first and second memories by the divider of the meter 20 and the value thereof is displayed on the recorder of the meter 20.
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