The synchronous switching scheme of dual power supply typically uses the voltage-current instantaneous DFT (Discrete Fourier Transform) algorithm to calculate the angle

frequency and amplitude. This algorithm needs a data window that exceeds half a power frequency cycle

which

in turn

increases the judgment and execution time of the control software. Consequently

the switching process between dual power sources switching process usually takes about 20 ms to 60 ms

potentially leading to voltage sag issues. To mitigate this

a novel undisturbed parallel flexible switching method is proposed. This method is based on the ultra-high-speed circuit breaker and can promptly switch to a backup power source in the event of voltage loss or internal short-circuit faults within the power grid. After clarifying the correlation between the millisecond response time of ultra-high-speed circuit breaker and system stability

the parallel flexible switching technology is deeply explored. A method that achieves transition balance of dual power supply parameter modules through the parallel connection of reactors equipped with ultra-high-speed switches is designed

thus reducing the algorithm's requirements and

in case of fault of power supply

ensuring undisturbed switching of the healthy area voltage. The efficiency of this method has been proved through verification on a high-voltage experimental platform. This study offers a new technological solution for enhancing reliability and stability of power systems.