Research on the method of observing the safety level of the grid cascading trip based on node injection power

Cascading trips generally occur in the early stages of major power outages. They are usually caused by power flow shifts after the initial failure. Although their form is relatively simple and if they are not adequately evaluated in advance, which will cause disasters in the power grid. Aiming at the grid cascading trip, this paper discusses the relationship between the occurrence of cascading trip and the node injection power, and presents a method for evaluating the current operating status of the grid to the safety level of the cascading trip. For this method, this paper firstly gives the expression of the current operating status of the power grid to the safety level of the cascading trip, and then uses this expression to further give a mathematical model describing the safety level of the grid to the cascading trip state. This model is an optimization model. Based on the DC power flow calculation method and the particle swarm optimization algorithm, this paper gives the specific algorithm flow of the optimization model. Finally, the calculation examples are demonstrated on IEEE-39 node system and IEEE14-bus system, and the results of the cases show the effectiveness of the model and method.