| 摘要 |
PURPOSE:To monitor safely and exactly the abnormality of a transmission line by transmitting the detecting signal via an optical cable to a monitoring station only when the signal of the sound collected with a microphone provided to a steel tower for the transmission line is abnormal. CONSTITUTION:The signal of the sound collected with a microphone 14 installed to a steel tower for a transmission line is compared with a reference signal So corresponding to an ordinary sound in a comparator 18 and if the signal is higher than the signal So, it is decided to be abnormal. A detection pulse P for abnormality having the frequency different with each of the steel towers is outputted from an oscillator 20 and is converted by a converter 22 to a light signal which is then transmitted via an optical cable 24 to a monitoring station 26 provided with a photoelectric transducer 28, a display device 30, etc. The abnormality including the fault that does not yet result in the disconnection of the transmission line is exactly monitored safely without the influence of electrical noise by the above-mentioned constitution which does not require the feeding of said pulse to the transmission line and transmits optically the signal. |
