There is a significant amount of unbalanced single-phase loads on the distribution network side, leading to areas in substation districts. In most regions, the degree of three-phase imbalance varies.
(2) The randomness and uncertainty in the process of customer electricity use, coupled with the increasing use of high-power loads, has increased the load on single-phase power grids and led to unbalanced three-phase currents.
The imbalance in three-phase frequency conversion power supplies can severely affect the power distribution network and the end-user. This is mainly reflected in the following aspects:
(1) Increasing power loss in line circuits, where current flows through the neutral wire in a four-wire distribution network with three-phase power, not only on the phase lines but also through the neutral wire during unbalanced three-phase loads, leads to power loss and adds to grid losses. Performance losses; Aviation ground power, 36V aviation power, 400HZ variable frequency power supply, 115/200V power supply, 27V DC power, 400HZ power supply, aviation power supply
(2) Increase the power loss of distribution transformers. As an important configuration on the low-voltage distribution network side, when powered by single-ended, single-phase power supply, distribution transformers can lead to increased distribution losses.
(3) The zero-sequence current generated by the distribution transformer increases with the increase of three-phase imbalance. Due to eddy current losses, the local temperature of the distribution transformer rises, leading to a shortened lifespan of the equipment.
(4) It affects the normal operation of electrical appliances and leads to a decline in power quality due to unbalanced three phases, thereby impacting the appliances' performance. Reducing unbalanced three phases can not only stabilize the quality of electricity in the power grid but also decrease power losses, saving energy.
