Limitation of short circuit current by an IS-limiter

The trend towards higher line kVA ratings and the permanently increase of the short-circuit contribution to a system leads to unacceptable high short-circuit currents. Reliable and economic protection against these high short-circuit currents is provided by the I
_S
-limiter. In case of a short-circuit-fault this fast-acting switching device triggers a small charge to open the main conductor, which is designed to carry high operating currents in normal condition. The current commutates to a parallel fuse with high breaking capacity, which limits the short-circuit current during the first rise within extremely short times. I
_S
-limiters are being used successfully in more than 2.800 stations in 85 countries.