The　safe　and　stable　operation　of　a　new　low-voltage　power　system　requires　the　research　and　application　of　fast　detection　technology　of　short-circuit　faults.　However,　the　existing　methods　are　difficult　to　effectively　realize　the　rapidity　and　reliability　in　case　of　short　circuits　with　unclear　features　and　various　interference　conditions.　Therefore,　the　fault　feature　of　short-circuit　current　in　the　full　phase　angle　range　is　analyzed,　and　a　new　method　of　short-circuit　detection　based　on　wavelet　packet　transform　and　current　change　rate　is　proposed.　Among　them,　the　fast-action　detection　method　of　wavelet　packet　transform　is　used　for　faults　with　obvious　features　to　achieve　detection　rapidity,　and　the　double　criteria　backup　detection　method　of　wavelet　packet　transform　and　current　change　rate　is　used　for　faults　with　unclear　features　to　ensure　detection　reliability.　On　this　basis,　the　hardware　technology　realization　of　short-circuit　fault　fast　detection　algorithm　is　studied.　For　short　circuit　faults,　load　startup,　load　switching,　and　other　situations,　the　real　low-voltage　AC　system　experiment　is　carried　out　to　verify.　Finally,　the　test　shows　that　the　detection　method　can　effectively　and　rapidly　detect　short-circuit　faults　within　1ms　in　the　full　phase　angle　range,　and　has　robustness　under　interference　conditions.　©　Published　under　licence　by　IOP　Publishing　Ltd.