The　application　of　HVDC　transmission　technology　in　power　systems　is　increasing　rapidly　while　the　currently　used　protections　for　HVDC　systems　operate　on　the　principles　which　have　poor　reliability　and　inadequate　sensitivity.　To　overcome　these　problems,　a　new　single-ended　transient　protection　scheme　is　proposed.　Due　to　the　boundary　characteristics　of　the　HVDC　transmission　line,　the　high-frequency　entropy　of　voltage　signal　is　significantly　reduced　that　when　passes　through　the　boundary.　According　to　the　difference　of　high-frequency　morphological　entropy,　criterion　to　distinguish　between　internal　and　external　faults　and　between　fault　and　sound　poles　can　be　constructed.　Morphological　filtering　is　used　for　singular　point　detection　to　construct　startup　criterion.　Based　on　the　PSCAD/EMTDC　electromagnetic　transient　simulation　platform,　a　simulation　model　of　a　±500kV　DC　bipolar　transmission　system　is　established　to　test　the　effectiveness　of　the　proposed　scheme.　Various　internal　and　external　faults　with　different　positions　and　different　transition　resistances　are　simulated　considering　noise　interference.　Simulation　results　show　that　this　scheme　can　reliably　identify　internal　and　external　faults　with　robustness　to　high　resistance　and　strong　anti-noise　ability.　©　2018　IEEE.