PURPOSE: To improve the locating accuracy, i.e. distance resolution by measuring the time difference from the signal from an accident current detector by using a radio wave which is sent from an artificial satellite and indicates time as reference pulses, and thus locating an accident point.

CONSTITUTION: Two accident current detectors 2 are installed on an overhead line 1 and a locating device 8 is installed on a steel tower. Further, a transmitting circuit 10 is provided so as to sends a signal to a center device 12 by a transmission line 11 such as an optical fiber cable. Then the reception time of a surge current is specified based upon the time signal 5 sent from the artificial satellite 4 in 1/100,000,000 units and compared with the surge current reception time from the other accident current detector 2 to detect the surge arrival time difference from the adjacent accident current detector 2, and the time difference data is sent from the transmitting circuit 10 to the remote center device 12 by the transmission line 11 to locate the accident point A. Consequently, the resolution of the time signal from the artificial satellite is 3m and the accident point is located with high accuracy.