Abstract: Most of the existing current limiter optimal configuration methods take resistive and inductive current limiters as configuration objects, and only consider the situation that each line is equipped with a current limiter, which reduces the economic benefit of the system. Therefore, an optimal configuration method considering the operating characteristics, position, and quantity of novel flexible fault current limiter(NFFCL) are proposed in this paper. Based on the simplified model of converter station and NFFCL, a DC system fault current calculation method with NFFCL is constructed, and its accuracy is verified in the 5-node DC system. The cost and current limiting effect of NFFCL are taken as the objective functions and maximum breaking current of circuit breaker is taken as the constraint, then an optimal configuration model is constructed, and the congestion calculation in NSGA-Ⅱ algorithm is improved to decouple the relationship between NFFCL installation quantity and capacity. Finally, the NFFCL optimal configuration scheme of 11-bus DC system is obtained by using NSGA-Ⅱ algorithm with improved congestion calculation, and the final scheme is selected according to the relationship among cost, installation quantity and current limiting effect.