Neutral line with voltage reasons - News - Global IC Trade Starts Here.
Low-voltage lines and equipment always have leakage current to the ground. It returns to the neutral point of the transformer through the grounding pole of the substation, and a voltage drop is generated at the grounding pole, so that the transformer neutral point and the neutral line carry a few volts. is normal. If this voltage reaches tens or even hundreds of volts, it must be caused by an electrical fault, which often causes an accident during electrical maintenance.
There are many reasons for the neutral line with fault voltage. For example, in the overhead distribution line shown in Figure 5, if the phase line is struck against the iron crossarm due to damage of the porcelain bottle, etc., the fault current Id is at the grounding pole of the distribution transformer. A voltage drop is generated across the grounding resistor RB such that the neutral line has a fault voltage Vf=Id.RB. 
The grounding fault on the high voltage side of the substation can also bring the voltage on the low voltage side neutral line. As shown in Fig. 6, the high voltage winding of the transformer penetrates the outer casing, or the high voltage cabinet busbar enters the ground fault due to the rat and the snake. The ground fault current Id is grounded. The voltage drop across the resistor RB also causes the fault voltage to be applied to the low-voltage neutral line because the protective ground in the substation of China and the grounding of the low-voltage side system share a grounding pole. 
In addition to the power frequency fault voltage, the neutral line can also sense lightning transient surge voltage, which can also cause damage to electrical maintenance personnel.
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