| 摘要 |
PURPOSE:To reduce speedily and securely the cost of construction and detect the generation point of a wire breaking accident by providing an optical fiber line which pieces photosensors provided at respective accident detection points successively and sends light to the respective photosensors in series. CONSTITUTION:Light pulse signal transmitters 7 and 8 are controlled by a pulse signal oscillator 6 to send out light pulse signals PA and PB continuously, and photocouplers 9 and 10 send them into the optical fiber line PL. If one wire breaking accident occurs between accident detection point (c) and (d), zero- phase voltage detectors Fd-Fn generate outputs although respective zero-phase voltage detectors Fa-Fc between a power station T to the accident generation point (c) are zero. Therefore, light which passes throgh the zero-phase voltage detectors Fd-Fn from the accident generation point (c) changes in plane of palarization to vary the level of a light pulse signal. Then, level variation detectors 13 and 14 connected to optical receivers 11 and 12 detect the points of time when the level varies and an accident point detector 18 calculates the time difference to detect the accident generation point.
|
