The invention discloses a protection method for a low-
voltage power grid, the low-
voltage power grid comprises a
transformer area intelligent terminal and a plurality of intelligent switches, the
transformer area intelligent terminal and the plurality of intelligent switches are connected through power lines, and the method comprises the following steps: establishing a longitudinal communication network between the
transformer area intelligent terminal and the plurality of intelligent switches; determining a
branch level of the low-
voltage power grid according to the voltage, the current, the power, the
electric energy and the alternating-current
zero crossing point; drawing an electrical topological relation of the plurality of intelligent switches based on the
branch hierarchy; establishing a transverse communication network of the plurality of intelligent switches based on the electrical topological relation; and when the power line has a
short circuit or a grounding fault, the fault area is
cut off through the corresponding intelligent switch, the fault information is broadcasted and the fault area is positioned through the transverse communication network, and the fault information is reported to the
station area intelligent terminal through the longitudinal communication network. According to the protection method, the fault area can be accurately positioned, so that the emergency situation of the low-voltage power grid can be efficiently and quickly handled in real time.