直流SMC铁心高温超导故障限流器的研究

Study of DC high temperature superconducting fault current limiter using soft magnetic composites

分析了直流电力系统保护的发展现状,设计了一种铁心型高温超导故障限流器。为了尽量延长限流的时间,限流器的铁心采用软磁复合材料(SMC)。限流器在系统正常工作时对电力系统影响很小,当短路故障发生时,它会很快表现为大阻抗以限制短路电流。基于磁场有限元与电路耦合的计算方法,首先对限流线圈在短路过程中的非线性电感进行精确计算,然后结合计算结果,在电路仿真程序中计算短路电流。通过对比SMC与硅钢铁心材料限流器的限流情况,可以看出SMC铁心限流器对于直流电力系统短路故障的限流效果更好。在短路故障发生后8 ms时,该限流器能将短路电流限制到最大值的12%。

The progress of the research on DC power system protection equipment is reviewed. A magnetic core direct current （DC） high temperature superconducting （HTS） fault current limiter （FCL） saturated by DC bias winding is presented. The core of SFCL is made of soft magnetic composites （SMC） to prolong the current limiting time. The inductance of the winding, which is connected in the power system to be protected, is small in normal operation. However, when a short-circuit fault occurs, the SFCL can provide large inductance to reduce the fault current. The design and analysis methodology of the SFCL is developed. The performance evaluation of the SFCL is peribrmed through numerical simulation by using 3-dimensional finite element analysis （FEA） of magnetic field coupled with the transient nonlinear circuit model. A comparison with silicon steel core FCL shows that the SMC core HTS FCL has rapid response to limit fault current and a good limiting effect. The maximum value of short-circuit current will be reduced to 12 percent at 8 ms.