Regional selective interlocking device

The invention provides a regional selective interlocking device comprising a first port, a second port, an input bus, an output bus, and a query signal receiving branch. The two ends of the input bus and the output bus are respectively connected with the first port and the second port. The first port and the second port can be switched between a state of being connected to the input bus and a state of being connected to the output bus. The regional selective interlocking device can work in a first mode in which the query signal receiving branch is switched on, and in a preset time slot, a link fault query signal is allowed to be input from one port to the query signal receiving branch and is blocked from being input from the other port to the query signal receiving branch, wherein the port is one of the first port and the second port. Whether a communication link connected with the corresponding port fails is judged according to whether a link fault query signal is received in the preset time slot. The regional selective interlocking device can automatically check communication links between switches of a power distribution system.