While special emergency avoidance,obeying the regularity-from generalization to specialization,differs them in its special situations and special manners in dealing with avoiding sudden dangerous cases.

Aiming at the specific out-phase grounding fault at the end of doublecircuit line on the same pole and taking TLS1B protection of GE corporation for example,the limitation of ordinary line protection is deeply analyzed,a unique application scheme of increasing signal channel and extending tripping enabling signal interface is proposed,with which the problem is solved in a better way.