Phase swapping type three - phase unbalance correction device compose by the main controller and phase converter. The main controller is responsible for collecting the real-time load data of the transformer area; analyze the load voltage and current of each phase converter; Form and send command to the phase converter. Equal voltage 0ms seamless phase change technology, phase changing will not interrupt the power supply. There is no inrush current in phase changing process, stable and reliable. Precise positioning phase converter ensures the balance of each branch of the distribution network hop by hop. No adverse effects on all kinds of electrical equipment.