The neutral line is also called the protected neutral line. Its main function is to protect personal and equipment safety, and secondly it performs the role of the neutral line.
In the three-phase four-wire system, assuming that the currents of the three-phase live wires are: i_a=√2I_a sinωt, i_b=√2I_b sin(ωt+π/3), i_c=√2I_c sin(ωt+2π/3), then The neutral current is the sum of these three.
Under ideal conditions there is no current on the neutral line. However, during actual circuit operation, various reasons may cause current to occur on the neutral line, such as unbalanced three-phase loads, excessive loads, and the presence of a large number of nonlinear components in the circuit. When the neutral current is too large, it will cause the neutral wire to heat up. In severe cases, it will burn the neutral wire and burn down the electrical equipment. Therefore, effective management and control must be carried out when the neutral current is too large.
So how to eliminate the neutral current? Is there any simple way?
First of all, it is necessary to determine how much current there is in the neutral line and the phase line when running at full load. This value can be easily obtained with a clamp meter.
Secondly, select the appropriate neutral current control device to control the abnormal current on the neutral line.
The above are methods that can fundamentally control the neutral current. If the above method cannot be adopted immediately, you can first use the following methods to alleviate it:
These methods can only play a mitigating role. When the neutral current is too large, it must be fundamentally controlled in time to prevent serious consequences.