The　key　to　the　intelligent　development　of　low-voltage　plastic　shell　circuit　breakers　is　to　achieve　real-time　and　accurate　detection　of　the　internal　current.　PCB　Rogowski　coil　has　the　characteristics　of　high　measurement　accuracy,　wide　measurement　frequency　band,　small　size,　and　low　cost.　Moreover,　PCB　Rogowski　coil　does　not　directly　contact　with　the　measured　primary　current　in　the　process　of　current　detection,　which　is　a　very　safe　method.　However,　the　internal　space　of　low-voltage　plastic　shell　circuit　breaker　is　compact　and　complex.　PCB　Rogowki　coil　placed　in　the　circuit　breaker　inevitably　is　interfered　by　various　factors　and　it　is　difficult　to　achieve　the　theoretical　high　precision.　This　article　makes　use　of　mathematical　analysis　to　identify　the　main　factors　that　affect　the　performance　of　PCB　Rogowski　coils,　including　the　influence　of　temperature　on　the　skeleton,　the　eccentricity　accuracy　of　the　measured　primary　current,　and　the　crosstalk　accuracy　of　adjacent　phase　currents.　Measures　are　proposed　to　reduce　or　even　eliminate　these　effects.　Through　the　analysis　of　these　main　factors,　a　three-phase　uniform　and　densely　winding　PCB　Rogowski　coil　with　equal　area　return　turns　is　proposed　in　this　article.　Finally,　the　experiment　verifies　that　the　eccentricity　error　does　not　exceed　0.2%　and　the　crosstalk　error　does　not　exceed　0.3%.　The　PCB　Rogowksi　coil　proposed　in　this　article　has　a　good　linearity　and　has　a　current　measurement　accuracy　of　0.5%.　©　2001-2012　IEEE.