| 摘要 |
<p>PURPOSE:To detect the abnormal current of a steel tower, by detecting the abnormal current of the steel tower as a damped oscillation current having frequency different at every steel tower, and transmitting the same to a central monitor station as a multiple light signal to discriminate the frequency in the signal. CONSTITUTION:An abnormal current I 1 flowing to the tower leg 2 of a steel tower is detected by the high frequency coil 3 of an abnormal current detecting part 1 attached in close vicinity to the tower leg 2 so as to cross the magnetic flux phi1 formed by the current I 1. The detecting part 1 is constituted of a coil 3, a condenser 4, resistors 5a- 5c, light emitting elements 6, 7 connected in anti- parallel relation to each other and an overvoltage preventing circuit 8 and output light signals of the elements 6, 7 are sent to an optical fiber 11. By this method, the lighting stroke current detected by the coil 3 is converted to damped oscillation current with constant frequency in the detecting part 1 and transmitted to a central monitor station by the element 6, 7 and the fiber 11. The electrostatic capacity of the condenser 4 is set to a value different at every steel tower and the frequency in the signal is discriminated in the central monitor station and the steel tower, where an abnormal current is detected, can be discriminated.</p> |
