Research On Evaluations Of Important Nodes And Lines And The Planning Of Backbone Grid In Power System

In recent years,the frequent power outage in the world have brought huge economic losses and seriously threatened social stability.Most power outages are caused by single power system or faults of transmission line and a few nodes,which lead to cascading faults.Strengthening the real-time evaluation of the important nodes and transmission lines of the power system will help to grasp the current operation of the power system in real time,and prepare for cutting off the accident transmission chain so as to improve the safety of the power system operation;predicting the important nodes and transmission lines of the power system in advance will help to grasp the important change trend of the nodes and transmission lines,and strive for sufficient early warning time for the grid company;planning the backbone grid in the built power system in advance and operating and maintaining its nodes and transmission lines by differentiating ways will help to ensure the power supply for special load in case of failure,accelerate the recovery speed,and reduce the adverse impact of failure on the power system.This paper focuses on power system nodes,transmission line evaluation and backbone grid planning and so on to make the research,the specific work is as follows:Because the Internet and power system can be abstracted as complex networks,Inspired by the SALSA(Stochastic Approach for Link Structure Analysis)algorithm for the evaluation of important web pages of the Internet,this research studies and designs the EB-SALSA(Electrical Bus-Stochastic Approach for Link Structure Analysis)algorithm for the evaluation of important nodes of power system by combining with power system operation mode,and the physical background and characteristics of nodes’ local topology and global topology.The simulation results show that the algorithm not only retains the characteristics of low time complexity of SALSA algorithm,but also has the advantages of high evaluation accuracy of important nodes,and comprehensively considers the influence of topology and operation mode on the importance of power system nodes.In this paper,the core idea of SALSA algorithm is combined with the physical background and characteristics of power system transmission lines,it studies and designs the EL-SALSA(Electrical Transmission Line-Stochastic Approach for Link Structure Analysis)algorithm for the evaluation of important transmission lines in power system.Because it is unable to model the important transmission lines intuitively according to the topological structure,this paper transmission line interaction relationship that is used in N-1 checking to build the model.At the same time,EL-SALSA algorithm also considers the local and global fault transfer structure between transmission lines and the operation mode of power system.The simulation results show that the algorithm has low time complexity and high evaluation accuracy.Even though the calculation complexity and speed of the important node and transmission line evaluation algorithm are low,there is still a delay between the results and the actual power system.Therefore,based on the above two parts of reserch,this paper studies and designs the K-M(K-means Markov chain)algorithm to predict the important nodes and transmission lines in the power system.In this algorithm,K-means algorithm and Markov chain are used to predict the important nodes and transmission lines of power system in the future from two aspects of data mining and prediction.At the same time,the initial clustering center selection mechanism of K-means algorithm is improved to make the clustering process more efficient.The simulation results show that the algorithm has large accurate nodes and transmission lines,and the average error is small.On the basis of the research on the evaluation of important nodes and transmission lines,this paper first abstracts the problem of power system backbone grid into a 0-1multi-objective optimization problem that needs to meet the constraints of power flow and connectivity,and on this basis,combining with the biogeography algorithm,it gives the planning method of power system backbone grid.At the same time,this part also improves the biogeography algorithm to make it competent for the 0-1 multi-objective optimization problem.The simulation results verify its rationality and effectiveness.