With　the　high　proportion　of　renewable　energy　integrated　into　DC　distribution　networks,　their　low　inertia　and　weak　damping　characteristics　result　in　high　peak　fault　currents　and　rapid　rise　rates,　posing　challenges　to　the　breaking　capacity　and　speed　of　existing　DC　circuit　breakers.　Therefore,　this　paper　presents　a　DC　fault　current　limiter　which　takes　into　account　ultracapacitor　fast-clamped　saturated　core　voltage.　The　current　limiter　uses　a　supercapacitor　to　rapidly　energize　the　saturated　core　in　series　with　the　main　circuit.　Upon　fault　detection,　a　single　phase　shift　control　is　used　to　enable　the　supercapacitor　to　discharge　quickly,　generating　a　specific　slope　current　in　the　saturated　core　to　clamp　its　voltage,　thereby　effectively　suppressing　the　fault　current　amplitude.　In　addition,　a　current　differential　criterion　is　used　to　distinguish　transient　and　permanent　faults.　For　transient　faults,　the　system　executes　self-recovery　without　circuit　breaker　operation.　For　permanent　faults,　the　clamping　voltage　of　the　saturated　core　is　further　increased　to　force　the　fault　line　current　to　zero,　enabling　the　rapid　operation　of　the　DC　circuit　breaker　to　isolate　the　faulty　section.　Finally,　a　multi-terminal　DC　distribution　network　simulation　system　is　established　to　verify　the　effectiveness　of　the　proposed　current　limiter.　The　results　show　that　the　proposed　current　limiter　can　effectively　suppress　the　fault　current　and　eliminate　the　negative　impact　of　faults　on　non-fault　regions.　©　2025　Power　System　Protection　and　Control　Press.　All　rights　reserved.