Short-Circuit Fault Current Phase-Controlled Switching Method Based on Fast Vacuum Circuit Breaker

The phase-controlled switching technology refers to controlling the breaking action of a circuit breaker when the current is in a specific phase, which effectively limits the arc energy of the contact gap and reduces the transient impact on power equipment and systems during the breaking process. Fast vacuum circuit breaker has advantages such as fast opening speed and low dispersion. When combined with phase-controlled switching technology, they are expected to achieve fast phase-controlled breaking of short-circuit currents. This paper investigates neural network zero-crossing point prediction algorithms and recursive least squares zero-crossing point prediction algorithms, designs a fusion phase-controlled strategy, and verifies through simulation that the prediction error of the fusion strategy is within 0.2ms, assuring accurate removal of short-circuit faults. The phase-controlled algorithm is developed and implemented on the STM32 embedded platform, and the device is tested through waveform recording experiments with the zero-crossing point prediction error of 0.13ms. Finally, phase-controlled breaking tests are conducted on a 1.8kV fast vacuum circuit breaker. The phase-controlled breaking device samples the loop current, predicts the zero-crossing point, delays according to the phase-controlled strategy after zero-crossing point, and successfully issues a breaking signal. The zero-crossing point prediction error is 0.07ms, validating the accuracy of the phase-controlled switching device.