Combinatorial Multi-Objective Optimization of Resistive SFCL and DC Circuit Breaker in Hybrid HVDC Transmission System

To cope with the DC fault isolation issue of a hybrid high-voltage direct-current (HVDC) system, a promising option is to coordinate superconducting fault current limiter (SFCL) and DC circuit breaker (DCCB). In this paper, a multi-objective Pareto optimization method is proposed for the combinatorial use of a resistive-type SFCL and a DCCB in a hybrid HVDC. Firstly, theoretical modeling and coordinated action process of the SFCL and DCCB are expounded. Then, a multi-objective function that collaboratively minimizes the SFCL resistance and the breaking capability of the DCCB is established, and a non-dominated sorting genetic algorithm-II (NSGA-II) is utilized to acquire the satisfying Pareto optimal solution set. The optimizing calculation is done in a 320 kV hybrid HVDC for validating the approach efficacy. Besides, transient simulations are implemented by PSCAD/EMTDC, and comprehensive performance analyses are executed to evaluate the rationality of the combinatorial optimal schemes. The findings indicate that the DC fault current is reduced and interrupted with the minimal rating of the resistive-type SFCL and the DCCB, and also, the HVDC system's safe and stable operation will be ensured. Therefore, the proposed approach is adequately verified for its availability and feasibility.