Reliability enhancement is always considered as the top priority of the power distribution network. It is highly expected that the power network faults can be locally addressed without spreading into the entire grid. To fulfill the requirement, this paper develops a smart power-electronics device named series soft open point (SSOP). The proposed SSOP connects two AC terminals and can suppress the surge current caused by a short-circuit fault. In addition, it also performs the grid-forming function during an islanding fault. The principle of SSOP will be elaborated and the effectiveness of this proposal is validated by experimental results.