Risk assessment of power system security based on component importance and operation state

With the great increasing of power system scale and complexity, the risk of power system operating security has been a focus for researchers. The power system security is not only involve the real operation state of the system, which is the practice of traditional assessment methods generally used, but also needed to synthetically consider other important issues such as the influence of system structure and the otherness of different components. This paper presents a new method for risk assessment of the power system security. First of all, from the perspective of systematology, a component comprehensive importance index model was built considering the inherent properties of components in the system. Secondly, an improved low-voltage severity index and an improved overload severity index were built via introducing the component comprehensive importance model into the risk assessment method as the weight factor. And then, a severity model was set to characterize the severity of the balance of grid power flow distribution and the load losing, basing on the operation state of the system and the power flow entropy theory, Therefore, a risk assessment method of power grid security based on both component importance and operation state was proposed, At last, the simulation results of IEEE-30 system illustrates the rationality of the proposed method to assess grid N-1 contingency risk and better accuracy in identifying the risk of every grade in N-k fault series comparing to the traditional methods, thus the validity and feasibility of proposed method is proved.