三相线 meaning in Chinese

triple-phase line

However , some unique geographical characters , such as fire grounding , bamboo grounding and treetop grounding , can cause single phase high - impedance grounding fault frequently . since the voltage drops down very little and the voltage among three phases keeps symmetric , this fault increases the difficulty of the check on this fault
然而，由火焰接地、毛竹接地或树梢接地等原因引起的单相高阻接地故障，由于电压降小、三相线间电压依然几乎对称，从而增加了高阻接地检测的难度。