Safety checking method for power system

The invention provides a safety checking method for a power system. The method comprises the following steps of: S1, determining a further equivalence date as required, and forming interface power flow of the equivalence date on a network scheduling side; S2, performing network equivalence calculation on the section of the equivalence date according to the interface power flow; S3, deriving the result of the network equivalence calculation on the section of the equivalence date to generate an equivalence file, and transmitting the equivalence file to provincial scheduling; S4, obtaining the equivalence file on a provincial scheduling side, resolving the equivalence file, storing resolved data into a defined outer net equivalence data structure to obtain an outer net equivalence model of the provincial scheduling, and splicing a provincial scheduling model with the outer net equivalence model of the provincial scheduling to generate a power flow section provided with the outer net equivalence model; and S5, performing safety checking calculation on the power flow section provided with the outer net equivalence model generated in the S4. Safety checking is performed in comparison to a use history and the current outer net equivalence model, so that the accuracy of an obtained result is increased greatly.