Solid State Electronic Fault Current Limiter to Limit the Fault Current in Power System

Increase in power generation capacity of electric power systems has lead to increase in the fault current level which can exceed the maximum designed short-circuit ratings of the switchgear. All the equipment therefore must have a short-circuit rating capable to withstand this level. Short-circuit currents contain extremely high energy and can damage electrical equipment. Typically, the circuit breakers open automatically in three to six cycles when a fault occurs. But circuit breakers, sometimes cannot handle the intense level of faults, as they are designed to handle designed faults current level so they fail to “break” and force a system to collapse. Advanced current interruption technology, utilizing high power Solid-State Fault Current Limiters (SSFCL) offers a viable solution to the transmission and distribution system problems caused by high system fault current. The SSFCL alleviates the short circuit condition in both downstream devices by limiting fault currents. To interrupt the current, SSFCL must rapidly insert an energy absorbing element (e.g. resistor) into the circuit to limit the fault current. A proper design of current limiting device will ensure that the fault current in the system is kept as low as possible in order to limit the surge current rating of the thyristor and also to minimize stresses on the power system network.