Assessment Of Restoration Scheme For Transmission Network Considering The Failure In Switching On Transmission Lines

After a large scale blackout, if some critical lines fail to be put into operation in the process of implementing the restoration scheme for the transmission network, the restoration process will be seriously affected. Therefore, the research of transmission lines for the impact of restoration scheme is very important for comprehensively assessing the reliability of the restoration scheme.Firstly, considering the time limit of generating units's startup, taking the shortest possible time to start the maximum capacity of the generating units as the objective function, and applicating cross-PSO and Dijkstra algorithm for network reconfiguration. Thus determined a new restoration scheme after the failure of a certain line.Considering the failed operation of lines in the scheme, a relative line betweenness is defined from the betweenness of the complex network theory in this paper. Furthermore, an importance degree of lines is put forward to identify the critical lines in the restore scheme for a transmission network.Based on the probability distribution of the risk that the lines fail to be put into operation in the scheme and the alternative optimum schemes after the lines in the original schemes failed to be put into operation, a risk assessment index is defined for the lines in the restoration schemes of the transmission network.The IEEE 30-bus system is used as an example to demonstrate the proposed method. The results show that the defined index can effectively identify critical lines, and evaluate the risk of different schemes. The proposed method makes further improvement on the assessment of the network reconfiguration, and has a practical value in guiding the restoration process.