Study On Grid-Based Fast Algorithm To Caculate The Transient Stability Margin Of Power System

The development of society and economic increases the demand of electric power with more stabiliy in power system. With the implement of the stratagy that power generates from west to east,networking and power market in China,the issue of dynamic security in large-scale power grid has been attentioned by researchers and engineering personnel. The purpose of on-line dynamic security assessment is to build an efficient, stable and protective architecture of power system operation. The architecture is set to monitor and simulate real time operation of power grid, propose dynamic information in details, suggestions of emergency treat, and efficiently enhance the stability, which is crucial to real time dispatching of large-scale power system. Stability margin is considered as a vital section of the protective architecture, the study on fast algorithm to calculate the transient stability margin of power system have been far reaching in reality.The basic method of transient stability analysis includes time domain method and direct method. Time domain method is adopted to precisely deal with all models in power system, which can nearly satisfy the requirement of the off-line computing speed and accuracy during the period of design ,planning and the operation of power system, but critical clearing time has to be obtained by repetitive computing, which requires long time enough and is not fit for on-line stability analysis, moreover, time domain method can tell yes or no,but it can not provide the stability margin. Direct method can supply the stability margin of system ,fast scan extreme parameters and the transient course, but it has two drawbacks, that is the rough models and the conservative result. Hybrid method mingles time domain method with direct method and becomes the best scheme of transient stability assessment in power system. Upon the previous scientific outcomes, this thesis presents a new hybrid algorithm based on Total transient energy function. The variation characteristic of the minimum of total transient kinetic energy in the post-fault duration for a contingency versus fault clearing times has been studied by vast scale simulation. Based upon the above characteristic,a novel approach for transient stability assessment is proposed. Case studies on the New England test power system and East China power grid in 2006 are presented to verify the effectiveness and efficiency of the new approach for stability margin estimate.To improve the speed of computing the transient stability margin of potential contingencies, the PC grid environment based on Windows XP and MPI is established. according to the contingencies, the parallel algorithm of transient stability margin based on MPI is presented. Cases studies on practical system indicate that the parallel algorithm of stability margin can get ideal speedup and parallel efficiency and owe extensive prospect of engineering application.