To provide a ground fault detection device capable of measuring a ground fault current highly accurately up to a minute value and capable of measuring insulation resistance highly accurately from immediately after a voltage change in a high voltage circuit.SOLUTION: One end of a detection resistor R2 for detecting a ground fault current is connected to a voltage reference point 10a of voltage output means 10, and current measuring means 30 measures voltage at both ends of the detection resistor R2 using a non-inverting amplifier circuit with the other end of the detection resistor R2 as input on the basis of the voltage reference point 10a. From a first measuring means output 41a which is a ground fault current value during an L voltage period of a rectangular wave voltage pulse output 10d, a second measuring means output 42a which is a ground fault current value during an H voltage period, and a difference arithmetic means output 45a of those difference arithmetic values, arithmetic means 40 obtains a difference in voltage at both ends of an injection capacitor C1 and a difference in voltage drops of the resistance of injection means 20 in both periods, and calculates an insulation resistance value.SELECTED DRAWING: Figure 1
【課題】地絡電流を微小な値まで高精度に測定が可能で、高電圧回路の電圧変化直後から高精度な絶縁抵抗測定が可能となる地絡検出装置を得る。【解決手段】地絡電流を検出する検出抵抗R2の一端が電圧出力手段10の電圧基準点10aに接続され、電流測定手段30が電圧基準点10aを基準に検出抵抗R2の他端を入力とした非反転増幅回路により検出抵抗R2の両端電圧を測定し、演算手段40が、矩形波電圧パルス出力10dのL電圧期間の地絡電流値である第1測定手段出力41aと、H電圧期間の地絡電流値である第2測定手段出力42aと、それらの差分演算値の差分演算手段出力45aから、両期間の注入コンデンサC1の両端電圧の差分、注入手段20の抵抗の電圧降下の差分を求め、絶縁抵抗値を演算する。【選択図】図1
GROUND FAULT DETECTION DEVICE
地絡検出装置
2023-03-23
Patent
Elektronische Ressource
Japanisch
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