Research On Power System Transient Stability Calculation With Variable Step Perturbation Method And Software Development

Now,China's power construction is developing rapidly,ultra-high pressure communication and DC system is improving the network continuously,the network structure is expanding gradually,the strengthening and complication of the link between each other is an inevitable trend.The stability of the power grid is becoming more and more prominent.In recent years,the blackout event also gave us a deep alert.Transient stability analysis is one of the three classic computations of power system,and it is also an important computational task for power system planning,design,scheduling operation and control.Therefore,the study of transient stability calculation of power system has important practical significance.Power system transient stability numerical calculation solves the system of differential algebraic equations in the time domain.In this paper,the following research work is done for the numerical calculation method of transient stability.1.The speed and accuracy of the transient stability numerical calculation have been the focus of the study.In this paper,a simulation method of power system transient stability calculation based on variable step size method and perturbation method is proposed to improve the simulation speed of numerical calculation,and a corresponding variable step size correction strategy is proposed.The characteristics of the algorithm include:(1)Use the perturbation method instead of the traditional Newton iteration method to solve the differential algebraic equation of the power system,the perturbation method has the same computational precision compared with the traditional Newton iterative method,eliminating the need for a large number of iterative calculations,reducing the amount of calculation,improving the simulation speed.(2)Under the framework of perturbation method to solve the differential algebraic equation,according to the variable step method and the local error theory and the estimated correction step size of the calculation format to make dynamic adjustment of the step,under the premise of ensuring the accuracy of the calculation,the number of steps reduce,which further improves the simulation speed compared with the fixed step.Variable step perturbation method theory is clear and the calculation process is concise.The simulation results show that the proposed transient stability method based on variable step perturbation method is effective.2.In the MATLAB graphical user interface(GUI)work platform,the main interface of the software is designed and embedded in the background program,and a power system transient stability calculation software-power system transient stability calculation V1.0 is developed.The software integrates a variety of generator models,a variety of transient stability numerical calculation methods,including the traditional algorithm described in chapter 2 and the perturbation method and variable step perturbation method described in chapter 3.Its main function has:(1)the user can choose a different simulation example;(2)the user can select the generator model,calculation method,fault type,simulation time and set;(3)it can display the curve of the generator terminal voltage changes with time and the rocking curve of the generator intuitively through the output interface.The software is intuitive,simple,image,user-friendly,and it is an open source software,but also improve and increase its functional modules constantly for users.