Fault Current Limiter

A fault current limiter, or FCL, sometimes called a fault current controller, is a device that limits the prospective fault current when a fault occurs in a power transmission network, without completely disconnecting the circuit. It maintains low impedance during normal operation but rapidly increases impedance when a dangerous fault current is detected, using nonlinear elements. Three main technology categories exist: superconducting devices that lose conductivity above a critical threshold, solid-state implementations, and inductive designs. Fault current limiters are particularly valuable for modern power grids incorporating distributed generation sources such as solar and wind farms, since they allow grid expansion without requiring costly upgrades to existing infrastructure.