单项选择题
A.顺调压 B.逆调压 C.常调压 D.恒调压
A.不超过0.2% B.0.2%～0.5% C.0.5%～0.8% D.0.8%～1%
A.2倍线电压 B.倍线电压 C.1倍线电压 D.1倍相电压