| 摘要 |
<p>PURPOSE:To enhance the reliability by providing a gate block by a thyristor rectifier at overcurrent detecting moment time, and then discriminating a defect by whether the output current of a thyristor rectifier is flowed or not. CONSTITUTION:When the output of a current transformer 11 provided at the AC input side becomes a set value or higher, a gate block signal 13-a is applied from a current detector 13 to a phase controller 9, and a thyristor rectifier 4 becomes a gate block state. The detector 13 detects the DC output current of the rectifier 4 from a branch unit 12 after generating the signal 13-a. When the DC current lower than the specified value is continuously flowed, it is judged to be an arm shortcircuiting defect to eliminate a gate block signal, while when not flowed, it is judged to be a field shortcircuit defect, and a main trip signal 13-b is output.</p> |
