对称Ｙ联接负载接于对称三相电源，不管有没有中线，两中性点电压都等于（   ）。

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SQL Error: select id,body,options from ***_enewstiku_ where sourceid='69471' and id < 4499878 and id<>'4499878' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku_ where sourceid='69471' and id > 4499878 and id<>'4499878' order by id asc limit 5