保护间隙动作后会形成截波，对变压器类设备构成威胁的是（  ）。

试卷相关题目

SQL Error: select id,body,options from ***_enewstiku_ where sourceid='69492' and id < 4501717 and id<>'4501717' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku_ where sourceid='69492' and id > 4501717 and id<>'4501717' order by id asc limit 5