(1) The grounding resistance of the transformer grounding wire is too large, if the low-voltage phase wire is damaged and grounded at the same time (for example, the L1 phase wire is grounded), then there will be current flowing in the transformer grounding wire, and the L1 phase voltage is added to the ground. And the grounding resistance, the greater the resistance of the grounding resistance, the greater the voltage divider on the grounding resistance. At this time, if someone accidentally touches the transformer grounding wire or neutral wire and the transformer housing, the human body will be connected in parallel with the grounding resistance, and the voltage applied to the human body will cause electric shock to the human body.
(2) When the grounding resistance of the neutral wire of the three-phase four-wire transformer is too large or the neutral wire is disconnected, the neutral point of the transformer will shift due to the unbalance of the three-phase load at this time, and the grounding point potential If it is not zero, some phase voltages will increase and the electrical equipment will be burned.
(3) When the grounding resistance is too large, the transformer and the arrester cannot discharge to the ground normally, causing the arrester or the transformer to burn out.
