1) Reduce the risk of a joint. If the neutral point is not grounded, when there is a touch to the ground, the grounding current is not large, the equipment can still operate, the fault may exist for a long time. If someone touches the leakage equipment, the current will pass through the human body back to the zero line through the equipment. At this time, the human body is subjected to almost phase voltage, which is very dangerous. When the above failure occurs, all electrical equipment connected to zero in the power network is in danger. At the same time, in the other two phases that do not touch the ground, the voltage to the ground also increases, greatly increasing the risk of electric shock.
2) Stabilize the system potential. Working ground can stabilize the potential of the system, limit the system voltage does not exceed a certain range, reduce the risk of high voltage into low voltage.
Transformer neutral points are: 1, ungrounded, 2, grounded, 3, by arc suppression coil grounding, 4, through the resistance grounding of four ways.