Case study of HTS resistive superconducting fault current limiter in electrical distribution systems

As electric power systems grow and become more interconnected, the fault current levels increase. Superconducting fault current limiters (SFCL) can limit the prospective short-circuit currents to lower levels, so that the underrated switchgears can be operated safely. In order to introduce SFCL into the electric power system, we need a way to conveniently predict the limiting characteristics in a given situation. We have developed an Electromagnetic Transient Program (EMTP) model of high temperature resistive type SFCL based on the electric field (E)–current density (J) characteristic of the superconductor. The SFCL in series with a circuit breaker could be practically used in electrical distribution systems. Case studies of EMTP simulations show that the SFCL cannot only limit the fault current to an acceptable value, but also reduce voltage decrease and the rise rate of the transient recovery voltage. In order to ensure the safe and proper usage of SFCL, some future considerations on the interaction between SFCL and power systems are presented as well.