Abstract:At present, there is a certain progress in the research of substation-area back up protection algorithm, but it lacks research on corresponding tripping strategy. This paper proposes a tripping strategy for substation-area back up protection based on graph theory. According to the topology structure of smart substation, the inter-substation connection relation and the breaker status information, the real-time substation component-switch correlation matrix and the inter-substation component-switch correlation matrix are formed, and then the substation component-switch relevance vector is established combined with the specific situation of the faulty component and the failure breaker. The breakers that need to be tripped in local backup protection, breaker failure protection can be accurately recognized by the relevance vector. The example analysis shows that the proposed method can be applied to the smart substation with complex main connections and changing operation modes, and can cut off the fault quickly with the minimum blackout zone.