Modelling and transient analysis of saturated core fault current limiters in electricity grids

Deregulation of electricity industry has shifted the operation paradigm of power systems in the recent years. Combined with the quest for energy efficiency and stringent environmental constraints, market regulation has driven the recent advert of decentralised generation. Transmission network expansion has also been affected as a consequence of deregulation, with network operators no longer being the sole authority over generation or network expansion planning. In this environment, the integration of decentralised generation at transmission and/or distribution networks has resulted in a considerable increase in the system fault levels that are unaccounted for in long-term planning forecasts by network operators. To enable higher integration capacity and reliable operation, these networks are also becoming more interconnected adding to the already increased fault current levels. As a consequence, at certain locations of the grid, the fault current levels are approaching or exceeding existing switchgear ratings.