Fully Controlled Hybrid Bridge Type Superconducting Fault Current Limiter

To date the diode-based bridge type superconducting fault current limiters (SFCL) developed can only limit the transient fault current, meanwhile the SCR-based bridge type SFCLs need up to ten milliseconds acting time to limit the steady fault current due to the inherent switching character of SCRs. To limit the fault current effectively and shorten the acting time to suit various power applications, this paper proposes a fully controlled hybrid bridge type SFCL using fast-response power electronic switches like MOSFETs and IGBTs. The circuit topology, control strategy and theoretical modeling of the proposed SFCL are presented in details. A 220 V/1 kA SFCL case is conceptually designed to study the operational characteristics of the proposed SFCL, and to compare with the conventional diode-based and SCR-based SFCLs. The results show that the proposed SFCL has the advantages of fast response to suit both fault occurrence and power system recovery, and has favorable ability to limit both the transient and steady fault currents.