The invention provides a partition interconnecting device, which comprises primary equipment and secondary equipment, wherein the primary equipment comprises a sending end voltage source converter, a receiving end voltage source converter and a DC connecting device; the secondary equipment comprises a control protection system; and the control protection system controls normal operation of the sending end voltage source converter, the receiving end voltage source converter and the DC connecting device in the primary equipment. Soft partition operation of an AC power grid can be achieved under the condition of not reducing the power supply reliability of an AC system; and an electromagnetic looped network is removed. During normal operation, the partition interconnecting device can achieve two-way control on power grid power flow; an AC fault can be isolated by the partition interconnecting device in a fault condition; a reactive power support is provided for the AC system; black startup can also be achieved; and the power supply reliability of the AC power grid is improved.