Integrated fault current limiter and power flow controller for grid tie-lines

The drive for higher reliability has motivated many utilities to move to a more meshed system. Increasing interconnection increases the reliability but on the down side also increases the fault current levels. High fault current levels increase the stresses on the existing circuit breakers, which are expensive to replace. Fault current limiters are used to reduce the fault currents below the ratings of the circuit breakers in order to prevent any permanent damage or malfunction of the circuit breakers. The paper proposes a dual device which not only can limit the fault current, but also can control the power flow through the transmission line in steady state.