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In recent years, the application of wireless sensor networks (WSN) in power systems has received a great deal of attention. As we all know, the most important issue for the power system is security and stability, especially due to the massive outages caused by cascading trips. Therefore, in today’s era, from the perspective of cascading trips, how to effectively use WSN to analyze and evaluate the security level of the power grid is an important direction for future power development. In this paper, an algorithm based on the WSN collection of online data to calculate the corresponding security level of the system is proposed for the cascading trip phenomenon, to achieve the online evaluation of the cascading trips. First, this paper proposes a hybrid layered network structure based on WSN for monitoring system and details the acquisition of power grid parameters by its acquisition layer. Secondly, combined with the manifestation of cascading trips and the action equation of current-type line backup protection, the mathematical representation of the grid cascading trips is given, and the mathematical form corresponding to the critical situation is strictly proved, and an index for evaluating the security level of the power grid is proposed and then further combined with the actual physical constraints of the power grid and the establishment of a mathematical model for calculating the security level of the grid cascading trips. For this model, this paper relies on evolution particle swarm optimization (EPSO) to give specific ideas for solving the model. Finally, a case analysis is performed by the IEEE39 node system and the results of the case show the effectiveness of the model and method.

This article introduces a method by which the power grid's security level can be observed in advance based on the expected initial failure. Firstly, based on the general form of cascading trip, this paper gives a mathematical expression of grid tripping based on cascading trip relay protection action behavior. According to the mathematical expression, the relationship between grid tripping and grid node injection power is discussed. According to this relationship, the distance between the node injection power under the current operation state and the nearest critical state node injection power is taken as the index to measure the power grid's security for cascading trip. According to this index, combined with various power grid constraints before and after the initial fault, a mathematical model for obtaining this safety index is given. This model is an optimized mathematical model. For the model, this paper gives a solution idea based on particle swarm. Finally, a few cases are performed in the IEEE-14 node system, and the calculations of the cases proved the accuracy of the proposed model and method.

With the continuous development of the smart wireless communications, the importance of electric energy becomes increasingly evident. Intricately interconnected power grids will also suffer from the threats of blackouts caused by grid cascading failure while bringing convenience to the masses. The grid cascading trip is closely related to cascading failure. Generally, the cascading failure shows a cascading trip at early stage. Hence, the avoidance of occurrence of cascading trip at an early stage may restrain the occurrence of complex cascading failure, thereby avoiding the occurrence of the blackout. In this paper, the occurrence principle of the cascading trip is firstly analyzed from the perspective of relay protection. The output of the generator is taken as the optimization variable, and the optimization model for restraining the grid trip is presented. Finally, the example of IEEE14 node system is analyzed in this paper in combination with the particle swarm algorithm, which verifies the rationality of the proposed method.

In this paper, a grid security index considering cascade tripping is proposed, and an algorithm is proposed for this index combination with the operating behavior of relay protection so as to solve the cascading tripping problem of the power system. Firstly, according to the current behavior of branch cascading tripping and the action of line current-mode backup protection, the critical state of grid cascading trip is analyzed, and it is proved that the input power of grid nodes can be used to describe the security of grid. Then, based on the relationship between the input power of nodes and the security level of power grid, a model is presented to represent the security level of power system without cascading failures under the impact of initial faults, and the model is solved by particle swarm optimization. An example proves the validity of the algorithm.