Unbalanced three-phase load in the low voltage distribution network not only increases the loss of transformer and line

but also affects safe operation of equipment. Therefore the control of unbalanced three-phase load has important practical significance. In this paper

the unbalanced mechanism and classification of the low voltage distribution network is studied firstly

and the constraint condition of unbalanced load control strategy is studied with combination of typical situation. Secondly

the principle and engineering application of several types of unbalanced control device of three-phase load is com-pared. Finally

the project verification is performed by way of selecting the scheme based on the intelligent phase transfer switch. It is shown by the 9-month’s operation data that the technology can solve the unbalanced problem of low voltage load of distribution network area

has such advantages as remark-able result

low cost and high reliability and is suitable for promotion and application.