Reliability evaluation of HV substations in the presence of Fault Current Limiter

Short circuit current is one of the major threats for power system stability. Power system should have the ability to detect and clear these faults within a specified time. The protection system can clear the faults only if the interruption capability of the circuit breakers is higher than the fault level. Expansion of the grid and installation of new power on the scale that is envisaged will require practical solutions to a number of technical challenges. One of the technical challenges is fault level management as system expansion often results in increased fault levels beyond the design limits of the existing switchgears. Replacing the old equipments particularly circuit breakers with the new ones having higher interruption capability is one way to overcome this problem. This, however, is not a cost-effective management of fault levels. Using Fault Current Limiters can be an alternative to avoid this high investment cost. In this paper, application of fault current limiter in substation reliability enhancement is presented. The result of the investigations carried out to assess the impacts of FCL application on substation reliability.