Electric power is output to the oil tube, which is connected with the bushing by the oil bushing connecter on the bottom of the oil tube, via a 3-phase transformer after AC-DC-AC inverse circuit. 电能由三相配电变压器经ACDCAC逆变电路输出传送到油管,经油管下部的油套管接触器连接到套管,形成一个完整的回路。