Designed fault locators are installed at sectional switches i.e.boundaries of sections, which in fact are resonant circuits connected to the feeder line in parallel to shunt the resonant frequency band component of the transient current. 在馈线各分段开关处即各供电区段边界处安装故障判断装置,其实质为并联在馈线上的谐振电路,使得在谐振频段附近的电流成分被衰减。