A Study on Wind-Turbine Generator System Sizing Considering Overcurrent Relay Coordination With SFCL

This paper analyses the effect of a superconducting fault current limiter (SFCL) on the optimal sizing of a wind-turbine generator system (WTGS), which is a representative renewable energy source. When the WTGS is connected to a radial distribution system, the level of fault current during a contingency is increased. This increased fault current can reduce the coordination time intervals (CTIs) between multiple overcurrent relays, which are an important factor in determining the optimal size of the WTGS. Moreover, the maximum capacity of WTGS is also restricted by the associated fault current level and CTIs in a power system. However, the SFCL can limit the fault current in the WTGS, and thus restore the original relay coordination. Consequently, this provides a chance to increase the maximum capacity of the WTGS. A case study is carried out to verify that the SFCL can be applied to determine the optimal WTGS size under the tightly constrained conditions resulting from the required protective relay coordination.