永磁饱和型故障限流器的高压大容量化分析

Feasibility Analysis on Developing High Voltage and Large Capacity Permanent-magnet-biased Fault Current Limiter

为提高永磁体的偏置能力以利永磁饱和型故障限流器朝高压大容量发展,从温度和外磁场两方面分析了钕铁硼永磁体的稳定性问题,论证了其应用到该限流器的可行性;提出"饱和深度比"的定义,指出改善永磁体的偏置能力与提高铁心的饱和深度比等价;基于一种结构参数可调的永磁饱和型故障限流器拓扑,分析了限流器结构参数与铁心饱和深度比的数量关系,并通过有限元法仿真以及实验加以验证;最后给出了10kV等级永磁饱和型故障限流器的一个设计实例。仿真与实验结果均表明,增加永磁体的厚度与截面积可获得较优的偏置能力,实现永磁饱和型故障限流器的高压大容量化在技术上是可行的。

The bias capability of the permanent magnet is still a pending issue as to hinder further development of the permanent-magnet-biased fault current limiter（ PMFCL） towards high voltage and large capacity. The temperatureand outside magnetic field-dependent stability of the Nd-Fe-B matrix permanent magnet was focused on. A concept of Saturation Depth Ratio was proposed and defined so as to improve the bias capability of the permanent magnet, and the saturation depth ratio of the iron core was analyzed. With regard to a novel PMFCL topology, the mathematical relationship between the structural parameters and the saturation depth ratio was obtained through equivalent magnetic circuit analysis. Finally, a case study of 10 kV prototype PMFCL was given together with finite element modeling. Simulation and experimental results demonstrate that, both increasing section area and length of the permanent magnet can achieve preferable bias capability, and thereby show technological feasibility to realize HV and large-capacity PMFCL.