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.