计及新型限流与断路器协同作用的直流配网故障隔离策略研究

Research on Fault Isolation Strategy in DC Distribution Networks Considering the Synergistic Effect of Novel Current Limiting and Circuit Breakers

针对直流配电网故障电流上升速度快、峰值高以及无法保证非故障区域供电可靠性的问题,该文提出一种应用于直流配电网的新型故障限流器,并对抑制故障电流峰值的桥式电路、加速故障转移速度的耦合电抗器以及通过斩波抑制故障电流的主限流支路进行理论推导和参数分析。基于电压微分判据和方向性过流保护原理,提出新型限流器与直流断路器的协同作用策略。在仿真系统中验证所提方案的正确性和有效性,并进行限流器的初步实验验证。结果表明,所提限流器能够有效限制故障电流,与已有故障隔离方案相比,采用协同作用策略降低了直流断路器至少90%的分断电流,成功避免了换流站闭锁,确保了系统的供电可靠性。

To address issues related to rapid increases in fault currents,high peak values,and the challenge of ensuring reliable power supply in non-fault areas within DC distribution networks,a novel fault current limiter for DC grids is proposed.The limiter design incorporates a bridge circuit to diminish peak fault currents,a coupling reactance for expediting fault transfer,and a primary current-limiting branch that employs pulse-width modulation to suppress fault currents.A coordinated strategy is introduced between the proposed limiter and DC circuit breakers,utilizing voltage differential criteria and directional overcurrent protection.The effectiveness and accuracy of the proposed solution are validated through simulation systems,and preliminary experiments are conducted.Results demonstrate that the proposed limiter effectively curtails fault currents,reducing fault current interruption by at least 90%compared to existing fault isolation methods.This successful implementation of the coordinated strategy ensures the avoidance of converter station lockouts and guarantees the system’s power supply reliability.