Efficiency of direct current system monitoring is changed with current transformer is improved formula that cut straightly connect, including connecting row seat device and grafting device, the fixed slot is offered including the wiring console to wiring console device on the wiring console, wiring console upper portion installation rotor plate, and one side of rotor plate is articulated with the wiring console, the bottom installation arc -shaped conductive sheet of rotor plate, the utility model discloses only need to rotate the fixed connection that can realize connecting row seat device and grafting device simultaneously that switches on that arc -shaped conductive sheet and electrically conductive inserted bar both can have been realized to the rotor plate. Operation process is simple, has improved new current transformer's change speed greatly. The utility model discloses an arc -shaped conductive sheet is arc -shaped plate structure, and the direction of arc -shaped conductive sheet arc is downward, makes arc -shaped conductive sheet prepare certain compression space, and when arc -shaped conductive sheet cooperated with electrically conductive inserted bar, arc -shaped conductive sheet can make through the compression have certain pressure decrease contact resistance between arc -shaped conductive sheet and the electrically conductive inserted bar.