Research On Characteristics Of Sub Synchronous Oscillation System Based On Eigenvalue Method

With the large-scale application of series compensation capacitor and HVDC transmission mode and the trend of generator unit parameters increasing,shaft length increasing and shaft rigidity decreasing,sub synchronous oscillation has become an important problem that threatens the safety of shaft system and power grid in China.The purpose of this paper is to analyze the characteristic analysis mechanism of the sub synchronous oscillating system with the integration of a kind of electromechanical network.For this reason,combined with the characteristic structure method,a subsynchronous oscillation system model including every module of the electromechanical network is established,and the linearized models of all components are deduced in detail.By solving and analyzing the eigenvalues of the system,The influence of series compensation capacitance and line parameters,generator shaft parameters,synchronous generator parameters and unit control system on the characteristics of subsynchronous oscillation system is studied in detail,and the corresponding laws are summarized.It is very helpful for guiding the actual project to design transmission lines and adjust the operation mode of the unit to avoid or suppress sub synchronous oscillation.It has great significance for improving the safety performance of the generating unit and improving the stability of the power grid.This paper also builds an electromechanical joint simulation platform based on the PSCAD time domain simulation platform,A custom shafting model is developed based on FORTRAN language,The model consists of two parts:the modeling of the multi segment centralized mass model of the shafting and the solution of the response of the shafting by using the transfer matrix method,The model instead of the components that support only six simple centralized models in the PSCAD,-The model uses CMSF to build the speed control system of the unit.The.simulation experiment is carried out by the electromechanical joint simulation platform,the results of the research on the parameters of the system are verified.