VSC-HVDC　has　received　extensive　attention　because　of　its　advantages　in　power　grid　expansion,　AC　systems　interconnection　and　large-scale　wind　farm　integration.　However,　faults　such　as　the　lockout　of　converter　valve　will　lead　to　power　surplus　and　voltage　instability,　which　will　cause　great　security　threats.　Therefore,　how　to　eliminate　surplus　power　and　stabilize　voltage　is　a　research　focus　in　this　field.　In　this　paper,　the　electrical　parameters　of　Zhangbei　Substation　are　adjusted　in　a　reasonable　proportion,　a　practical　model　of　wind　farms　and　connected　power　grid　are　constructed.　The　model　cleverly　reflects　the　operating　status　and　technical　characteristics　of　Zhangbei　Substation.　Based　on　that,　the　effect　of　energy　absorbing　device　switching　operation　(timing　coordinate　with　wind　turbines　and　switches)　on　the　islanding　system　when　the　converter　valve　is　locked　is　researched　by　using　electromagnetic　transient　simulation,　which　demonstrates　its　significant　effect　on　absorbing　the　surplus　power　and　maintaining　the　stability　of　voltage.　Possible　failures　of　the　energy　absorbing　device　itself　during　the　switching　process　have　also　been　studied.　Furthermore,　the　trend　of　system　power　and　voltage　varies　with　the　fault　security　is　researched.　The　conclusion　provides　theoretical　support　for　the　fault　analysis　and　troubleshooting　strategies　of　the　energy　absorbing　device　in　VSC-HVDC　project.　©　2020　Institution　of　Engineering　and　Technology.　All　rights　reserved.