A.5% B.10% C.15%
A.安裝,發(fā)電,變電,配電,用電 B.安裝,發(fā)電,變電,送電,配電 C.發(fā)電,變電,送電,配電,用電
A.±0.2Hz B.±0.5Hz C.±0.3Hz