Backup protection method and system used for 10-kV outgoing line and based on station domain information

The invention provides a backup protection method and system used for a 10-kV outgoing line and based on station domain information. The method comprises the following steps: monitoring the operation state of a protection device of a target line of a 10-kV-side outgoing line through a heartbeat mechanism, and when the heartbeat is normal and if the operation state is normal, ending the process, or if the operation state is abnormal or the heartbeat is overtime, detecting action information of a protecting direction element of an in-situ layer; and if the action information is that a fault direction does not point to a 10-kV bus, or a protection direction element of a non-target line of the 10-kV-side outgoing line judges that the fault direction points to the non-target line, ending the process; or otherwise, sending an instruction to a circuit breaker of the target line of the 10-kV-side outgoing line. According to a scheme in the invention, the action information of direction elements for in-situ transforme