智能变电站中，交换机VLAN配置的必要性（ ）。

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SQL Error: select id,body,options from ***_enewstiku where sourceid='29469' and id < 2398889 and id<>'2398889' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku where sourceid='29469' and id > 2398889 and id<>'2398889' order by id asc limit 5