混合式限流断路器阶段分析及其控制策略优化

Stage Analysis of an AC Hybrid Current-limiting Breaker and Its Optimization of Protection Control Policy

针对传统真空断路器在微电网无缝切换时遇到的分断速度慢的问题,提出基于高速机械开关和固态断路器新型混合式交流限流断路器的设计方案。对该断路器在预期短路电流20 k A的工况下换流分断过程分阶段进行了分析,推导了限流断路器短路分断时间的计算公式,并进行了不同关断电感下的模拟仿真以验证所建模型的正确性。在分析结论的基础上完成了限流断路器关键器件参数的设计。通过对分断保护控制策略的优化,有效减小了触头分离时电弧的大小,提高了短路限流分断性能。经仿真试验改进后的400 V/450 A混合式限流断路器可以将预期短路电流20 k A的故障电流限流至4 200 A以下并完成分断,短路分断时间仅不到1 ms。

To solve the problem that traditional vacuum breaker can not meet the requirements of fast breaking when seamless switching in micro-grid, an AC hybrid current-limiting breaker （HCLB） based on high-speed me- chanical switch and solid state circuit breaker is proposed. In this paper, the hybrid breaker＇ s commutation and in- terruption process are analyzed when prospective fault current is 20 kA and the formulas of separation time in short circuit protection period are deduced, which is validated with different inductance by computer simulation. The de- sign of parameters are put forward based on theoretical analysis. After optimizing the protection control policy, the arc current between the contacts during separation reduces significantly, which could improved current-limiting a- bility and interruption performance of the breaker. After improvement by simulation, a 400V/450A DC hybrid cur- rent-limiting breaker has been developed and the computer simulation shows that the prospective fault current of 20 kA is limited to the value below 4.2 kA and the entire interruption process takes less than 1 ms.