TRANSMISSION LINE ACCIDENT MONITOR

PROBLEM TO BE SOLVED: To dispense with maintenance and inspection of power sources by constantly charging capacitors of large cpacity as an earth monitor power source and a magnetic field sensor power source, and using a super-capacitor constantly charged from them as a backup power source. SOLUTION: An earth monitor 3, an earth monitor power source 4 and a magnetic field sensor power source 5 are enclosed in a box 1. A magnetic field sensor 6 and a transmission line current monitor connoting of an amplifier are enclosed in a box 2. A main control circuit 7 and a backup power source 8 are enclosed in a box 3. The earth monitor power source 4 and magnetic field sensor power supply 5 consist of capacitors of large capacity of 100 μF, for instance, connected to secondary coils of current transformers CT, CT through rectifying circuits and constantly charged. The backup power source 8 is formed of a super-capacitor of extremely large capacity of 100F, for instance, and constantly charged with a micro current from the earth monitor power source 4. Since capacitors are used for the operating power sources of a device, periodic maintenance and inspection of the power sources is dispensed with, with few failure.