Research On Transient Stability Simulation Based On Component Tree Model And Bi-Directional Iteration

As the nation-wide power grid of China has been basically established, power system real-time simulation becomes a necessary tool for implementing on-line dynamic security analysis (DSA). A new fast simulation approach, component tree model and forward/backward iteration based power system transient stability simulation approach, was proposed in this paper. This research included power network partitioning, structured description of the simulation model, computation of correction factors, the overall procedure, measures to speedup the computation, and scheme of parallel implementation.Based on the regional characteristics of realistic power grid and contour tableau partitioning, a systematic partitioning method was proposed to decompose large-scale power network into tree structure. A new concept, power system component tree, was proposed to describe the overall power system briefly. The power system component tree can reflect the result of power network partitioning and the distribution of power system components. A component tree based description approach was developed to represent the simulation model of the power system. The feature of this description approach is that the model of the components are normalized and structured.A bi-directional iteration technique was proposed to calculate the correction factors of variables in the simultaneous solution of power system equations. The correction factors of variables were computed through a serial of operations called "forward reduction" and "backward evaluation". The algorithm of component tree model and forward/backward iteration based power system transient stability simulation was presented. Measures to speedup the computation and parallel implementation of the proposed approach were also investigated. In case studies, the simulation result obtained by the new approach is compared with that of BPA, a kind of power system commercial simulation software. The comparison validates the correctness of this new approach.This new approach inherits some attractive features of the simultaneous solution method such as numerical stability and fast convergence; it also possesses advantages of high computation efficiency, good expansibility and ease of parallel implementation. It would be potentially useful in developing real-time tools for online DSA applications.A novel concept called oscillation energy function of bus power was proposed in this paper. On this basis, a control strategy, named oscillation energy function descent...