Complex network theory based recognition of power grid key line

The probability of power system cascading failure is very small, but once happened, its influence is disastrous. There are a few key branches play an important role in the process of cascading failures in power system. The identification of these key branches is of great significance to the safe and stable operation of power system. Power system transmits active power and reactive power at the same time. Different from the full range of active power, the reactive power has the characteristic of regional decoupling. The impact is generally limited in the vicinity of fault branch, so this paper temporarily only considers active power. Firstly, in this paper, the only link line between two subsystems is detected. If the branch is the only link line, it is the key branch. If it is not, then make the power flow of the fault branch as the basic parameters, and reduce the active power flow in the relevant branch of the fault branch to the fault branch by the power grid topology. Then get the grid key branch identification evaluation indicator. Finally apply the evaluation indicator in practical example of IEEE 39 bus system, and the result conform to the actual operation characteristics of IEEE 39 bus system and prove the correctness and effectiveness of the method.