Analysis Of Shanxi Power Grid Transient Stability Based On PSASP

With the comprehensive implementation of electric strategy of "deliveringpower from west to East,exchanging between north and south and enhancingnation-wide interconnection", until 2020,China will build a extra-high voltageand AC/DC hybrid transmission system with the feature of spanning-region andlong-distance transminssion high power which seldom appeared in theworld. but, followingly, Security and stability are the most important issues inelectrical power system.If power system is unstability, it will cause large-scaleblackouts and bring considerable economical loss.In order to ensuringlarge-region power stability, every region's stability is basis,shanxi is bigprovince in transmissing power and play an important role in Chinanorthern.This paper mainly analysize power grid stability theory and stability of500kV system of shanxi power grid,by syudying all kinds of fault in line,aiming at instability, some actions should be put forward.Currently, there are the time-domain simulation method, direct methodsand hybrid method in power system transient stability analysis.the time-domainsimulation method is still mainly method, but the degree of stability margincan not offered and have to be seeked through reiterative integral calculation, calculation strenuous;direct method can give the degree value of stability, but theadaption of model is simple,energy function is difficultly gave;hybrid methodhave the advantages of time-domain simulation and direct method,speed ofcalculation is quickly, it is very prospective for on-line use.This paper depicts basic concepts and classification of power systemstability, summarizes and compares the method of studying power systemtransient stability, introduces the structure and function of PSASP which isdeveloped by China Electric Power Research Institute,and studies from two tosix rank model of generator, excitation system, prime mover and its governorsystem and load model, analysizes and compares the influency of inertia timeconstant,power system stabilizer and load location on transient stability.On the basis of consulting to a great deal of relaed data, analysizingelectric main-line diagram of shanxi power grid, according to regions, inputtingdata to PSASP and forming primary and common database; choosing a kind ofpower flow style and calculating to get a more suitable result, which is initialvalue of transient stability.At the course of calculating, using method oftime-domain simulation, load model is choosed 40% constant impedance and60% inductive motor.Finally, according to《Power System Security and Stability Guide》,thisthesis takes simple-phase and three-phase fault as mostly fault style of stabilityverification,transient stability of 500kV system is studied.Up to 2006,there areeighteen 500kV AC-lines in the grid.When these lines respectively happens simple-phase instantaneous and permanent fault, three-phase opening on thecondition of no fault and fault in no reclosure,system basically meet request ofstability.In the same time, the influence of generator and load model on transientstability is analysized.this paper analysizes the interface of middle-to-southpower transmission, power flow of interface and critical clearing time andstability margin is educed.By transient stability N-1 and N-2 calculation,powerangle stability and voltage stability meets request.