Simulation study of integrated‐gate‐commutated‐thyristor based superconducting hybrid direct current circuit breaker

Abstract With the development of a distributed generation, direct current (DC) load and energy‐storage equipment, voltage‐source‐converter‐based medium‐voltage DC systems (VSC‐MVDC) have attracted more attention due to its low power consumption, high reliability, independent power control and so on. However, VSC‐MVDC has the problem of DC fault isolation, which requires the fast‐acting DC circuit‐breakers to isolate faulty lines and ensure low cost. This problem can be solved by coordinating resistive type superconducting‐fault‐current‐limiter (R‐SFCL) and integrated‐gate‐commutated‐thyristor (IGCT) based hybrid circuit breaker. Based on this, IGCT based superconducting DC circuit breaker (SDCCB) is proposed and analysed. Combining R‐SFCL with IGCT could realise large current limiting and interruption and ensure low cost. In addition, the IGCT based hybrid DC circuit breaker (IGCT‐HDCCB) is compared with the traditional insulated gate bipolar transistor (IGBT) based hybrid DC circuit breaker (IGBT‐HDCCB) to evaluate which circuit breaker is more suitable for VSC‐MVDC. The results show that, coordination based on R‐SFCL and SDCCB, the fault current is successfully limited from 17.6 to 2.1 kA, and then interrupted within 3.8 ms. In addition, IGCT‐HDCCB overcomes the disadvantage that IGCT has less interrupting capacity than IGBT, retains the advantage of low cost of IGCT and is more suitable for MVDC system.