| 摘要 |
PURPOSE: An apparatus for detecting whether the differential current use in a direct current signal line is ground and a method for the same are provided to previously prevent the accident during the maintenance of the control and measurement system, thereby drastically improve the quality and reliability of the product. CONSTITUTION: An apparatus includes an analog current(AC)/digital current(DC) sensing device, an analog to digital converter, a central processing unit(CPU) and a detector. The AC/DC sensing device is installed on lines A and B to measure the current of a fine direct current measuring device. The analog to digital converter converts the voltage received from the AC/DC sensing device into a digital valued at the digital converting block. The CPU is provided with a current converter, a differential current absolute value calculation block, line voltage selection block, a ground resistance calculation block, an alarm value setting block, a comparator and an alarm generation block. And, the detector includes a monitor to display the ground resistance calculated by using the measured current, the differential current and the ground resistance in the form of trend and number.
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