Research on The Switching Characteristics Of Dual Power Transfer Switches

With the increasing demand for power supply continuity in industrial power systems, dual power transfer switches are widely used in 6kV industrial distribution systems. However, they commonly face problems such as the rapid decay of bus residual voltage and excessively large inrush currents during the switching process, resulting in a switching failure rate as high as 18%. This paper constructs a transient simulation model of 6kV dual-power switching based on ETAP software, with induction motors as the core load. Two typical operating conditions (motor capacities ranging from 20-35 MW, phase angle differences from 0° to 180°) are set to quantitatively analyze the correlation mechanism between the transient drop rate of the bus residual voltage and the inrush current. A 'dynamic phase angle-time coordinated control strategy' is proposed. By real-time monitoring of the characteristics of the bus residual voltage, for induction motors with a capacity of 1825 MW, a fast-switching strategy is preferably adopted; for induction motors with a capacity of 25 - 30MW, a synchronization- capture control strategy is used.