不受电力系统振荡影响的继电保护有（    ）。

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SQL Error: select id,body,options from ***_enewstiku_ where sourceid='69487' and id < 4500898 and id<>'4500898' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku_ where sourceid='69487' and id > 4500898 and id<>'4500898' order by id asc limit 5