The invention relates to a plug-in coupling system for the transfer of high-power energy and for the transfer of a fluid under pressure, consisting of at least one coupler plug (2, 2′) and at least one coupler socket (3, 3′) with at least one electrical conductor (4, 5), respectively. The coupler plug (2, 2′) can be introduced into the coupler socket (3, 3′) to produce a coupled state and can be removed from the coupler socket (3, 3′) to produce a decoupled state. The plug-in coupling advantageously comprises at least one electromechanical protection system consisting of at least one electronic switch means (35) and at least one mechanical switch means (4, 11), arranged inside the coupler socket (3) and/or the coupler plug (2), said mechanical switch means establishing or separating the electroconductive connection, the electronic switch means (35) and the mechanical switch means (4, 11) being independently controllable.