Under normal operation of the system, the unbalanced capacity and electrical location of single-phase loads (such as electrified railways, electric arc furnaces, and electric welding machines) in a three-phase system will cause the three-phase imbalance in the system.

　　The harm of three-phase imbalance: it will cause the neutral line current to increase, thereby increasing the power loss of the line; it will cause local heating and aging of the neutral line, and even a fire; it will cause the impedance drop of the neutral line, which will cause the neutral point to drift and the zero-ground voltage to be high Safe operation of microcomputer-based electrical equipment; resulting in reduced processing of distribution transformers and increased losses, which can easily cause the distribution transformer to heat up or even burn out.

　　Significance of controlling three-phase imbalance: reducing the neutral current and avoiding neutral line heating; avoiding problems that endanger the safety of electrical equipment caused by voltage drift at the neutral point; avoiding reduced output and heat generated by the distribution transformer due to three-phase imbalance Wait for a series of questions.