However, some unique geographical characters, such as fire grounding, bamboo grounding and treetop grounding, can cause single phase high-impedance grounding fault frequently.

• 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。