Study of the Application of Active Saturated Iron-Core Superconductive Fault Current Limiters in the VSC-HVDC System

As a typical inductive type superconductive fault current limiter (SFCL), the saturated iron-core SFCL (SI-SFCL) is very important to the safety of the VSC-HVDC system. Considering that the high-induced voltage of the superconductive winding may cause damage to the dc-bias source, an active SI-SFCL, which can quickly cut off the dc-bias source branch, is introduced to limit the dc fault current. This paper first describes the building of a transient analysis model of the active SI-SFCL and, presents the VSC-HVDC system equivalent circuit with the active SI-SFCL deployed. Moreover, the method of solving the state equations of the equivalent circuit is obtained. On this basis, the influence of the protective voltage of the metal oxide arrester on the current-limiting performance is studied. Finally, the correctness of the transient analysis model, and the effectiveness of the theoretical analysis method are verified by MATLAB/Simulink simulations.