Accident-point locating method of power cable

PURPOSE:To provide an accident-point locating method wherein an accident point can be oriented by means of a simple system which uses at least one optical fiber as a transmission line transmitting the detection signal of an accident and the mounting position of a sensor is restricted comparatively little. CONSTITUTION:When a dielectric breakdown accident is caused at power cables 1 or their connection parts 3, 4, a large acoustic signal is generated. Sensors 6 detect the acoustic signal and give it to optical modulation means 7, 8. The optical modulation means 7, 8 modulate an optical signal propagated on an optical fiber 10 by means of output signals from the sensors 6. The optical signal on the optical fiber 10 is given to a judgment means 11; the accident point of the power cables is oriented. Since it is sufficient to lay at least one optical fiber along the power cables 10, a system can be constituted simply. When the arrival time difference of the sound signal up to the sensors 6 is utilized, it is possible to find the distance up to the accident point from the sensors 6.