Completely distributed island division method and system based on intelligent terminal unit

The invention provides a fully distributed island division method and system based on intelligent terminal units. The method comprises the following steps: acquiring each DG node of a power distribution network, installing an STU at each node of the system, and installing a circuit breaker at the wire inlet side of each node of the system; fault information of a superior power grid or a transformer substation outlet is collected, and when a fault signal is obtained, the STU closest to the transformer substation outlet sends the fault signal to the downstream STU in the power distribution network; after the STU of the downstream DG node of the fault point receives the forwarded fault signal, the STU is used as a starting point, and island division based on heuristic rule island range gradual fusion is carried out in parallel; after island division is finished, an island boundary switch is switched off, grid connection is carried out again in a DG conversion control mode, and power supply of loads in an island