Relay protection on-line check sequence ordering method based on branch circuit importance degree

The invention relates to a method used for ordering importance degree of relay protection in a power system network and particularly relates to a relay protection on-line check sequence ordering method based on the branch circuit importance degree. The method comprises a step of determining a generator-branch circuit power distribution factor and a load-branch circuit power distribution factor; a step of determining branch circuit power according to the generator-branch circuit power distribution factor and the power unit generating capacity; a step of determining a branch circuit-load power distribution factor according to the calculated branch circuit power; a step of determining a generator-load pair power distribution factor according to the branch circuit-load power distribution factor; a step of determining a structural importance degree factor of a branch circuit; a step of determining the flow transferring degree of the branch circuit; a step of determining the probability importance degree of the branch circuit; a step of determining the comprehensive importance degree of the branch circuit; and a step of determining the importance degree of a protection device corresponding to the comprehensive importance degree, so that a protection on-line check sequence is obtained. According to the method provided by the invention, indexes of the structural importance degree and the probability importance degree of the branch circuit can be obtained without performing the complex power flow calculation. The method provided by the invention is more direct and effective compared with a traditional method.