REMOTE MEASUREMENT METHOD FOR SUBSCRIBER CIRCUIT AND REMOTE SWITCHING CIRCUIT FOR SUBSCRIBER CIRCUIT

PURPOSE:To prevent the circuit switching circuit from being operated by mistake due to the induction of a short and high voltage such as lightening by providing a charge circuit charged by a unipolar high voltage to the switching circuit. CONSTITUTION:Since a resistor R2 used to discharge a charge of a capacitor C2 is connected in parallel with the capacitor C2, the charge in the capacitor C2 gradually decreases with lapse of time after a prestep is finished. The resistance of the resistor R2 and the capacitance of the capacitor C2 are controlled properly, after the transmission of a unipolar high voltage is once stopped in the prestep, when a unipolar high voltage is impressed in an open step within 0.5sec, the opening is implemented and even when a high voltage is impressed in the open step after lapse of time, it is invalidated. That is, since the thing as above seldom takes place in the natural phenomenon such as lightning, malfunction of the switching circuit due to lightning or the like is avoided.