New　electronic　current　transformers　(ECTs)　often　adopt　a　circular　array　of　magnetic　sensors　for　the　large　current　measurement　without　iron　cores.　However,　the　position　of　this　ECT　on　the　measured　conductor　will　directly　influence　the　current　measurement　accuracy.　In　this　study,　we　build　a　3-D　magnetic-field　model　which　is　used　to　analyze　the　impact　of　the　magnetic-sensor　circular　array　position　on　current　measurement.　To　meet　the　accuracy　Class　1.0,　we　estimate　the　necessary　magnetic　sensor　number　and　the　acceptable　position　deviation　of　the　ECT.　Finally,　a　new　ECT　with　the　circular　array　of　seven　magnetic　sensors　is　designed　and　implemented,　which　is　used　to　validate　the　simulation　analysis　of　the　ECT　position　deviation.　©　2018　IEEE.