Why do we need three phase unbalanced power supply?

Usually three-phase or single-phase loads both used in in a three-phase house that will lead to three-phase unbalanced consumption，which will cause that some phase is picking energy from grid while other phase is feeding in grid.
In addition， some countries grid utility requires different export limit, this will need inverter has different export control way to match. (the different of total export limit and per phase export limit)
For per phase export limit scene, we suggest to enable the three phase unbalance function.