Design and analysis of a peak current-limiting device using an oscillating zero-crossing circuit

Abstract

Excessive short-circuit currents present a significant threat to the operational stability of equipment in the industrial and mining enterprises distribution networks. To address this challenge, a novel short-circuit current-limiting strategy is proposed in this work, which combines an LC high-frequency oscillation circuit with a power frequency current circuit in parallel. The configuration forces the short-circuit current to reach the zero-crossing point, promoting electrical disconnection in a vacuum environment. The presented strategy integrates an ultrafast vacuum circuit breaker with a mechanical breaker, which is connected in parallel with an LC oscillation circuit designed to enforce zero-crossing interruption of the main circuit. Additionally, a current-limiting reactor is utilized to effectively suppress the short-circuit current. Furthermore, the working mechanism of current-limiting device, the design of its key parameters, and the potential applications in actual distribution networks are also analyzed. Both simulation and experimental results confirm that the designed device effectively reduces the peak short-circuit currents to below 70 %, significantly mitigating their impact on distribution network equipment and greatly enhancing the operational stability of system.