Study On Reclosure Technique Based On Branch Transient Potential Energy

With the growing stress on today's power system due to interconnected electric transmission systems and open access competitive electricity markets, many utilities are under the threat of transient problem. Consequently, security assessment and transient stability control have been paid more and more attention by power system analysts and researchers. Although the advances have been made over decades, the difficulties on one-line dynamic security assessment and implement of emergency control still exist owing to network-reduced system model on the frame of COI. The method of calculation of line potential energy based on structure preserving model, provides that the global issue of power system stability can be converted into local issue, which is the novel view of the on-line dynamic security analysis, monitoring and control.Automatic reclosure technique will enhance power system transient stability. The main research of the optimal reclosing time is the issue of stability and control. Automatic reclosure can be considered as the method of stability and control. Based on structure-preserving Topological Energy Function for multi-machine power system, the feature of line transient energy distributing over network after a transient fault has been analyzed. Setting method on instantaneous fault reclosing time and permanent fault reclosing time is proposed which is based on network dynamic variables. The simulation in single-machine and multi-machhine indicates that this method enables to damp the interconnected power system oscillation effectively after reclosing time and improve transient stability. In the premise that it is difficult to use adaptive setting laws of optimal reclosing time for permanent fault on line, the range of reclosing time and practical adaptive setting laws are proposed. On-line forecase of optimal reclosing time is realized. The simulation effectively indicates that the method can improve power system transient stability.