On the Analysis Methods of Subsynchronous Oscillation Caused by Power Electronic Equipment

摘要

In this paper, the methods for analyzing power system subsynchronous oscillation are reviewed, and two commonly used methods, the complex torque coefficient mehtod and the eigenvalue analysis method are checked in detail. Two related problems in applying the two methods are studied thoroughly. One problem is the validity of the complex torque coefficient method to the multi-machine power systems, and the other problem is the applicability of the quasi-steady state models of power electronic equipment in the anlysis of subsynchronous oscillation. It is pointed out that the complex torque coefficient method has unique strong point when used to analyze the subsynchronous oscillation problems caused by power electronic equipment if the method is realized by time domain simulation. The realization of the complex torque coefficient method by time domain simulation is established in the paper. Using the time domain simulation mehtod, the complex torque coefficient of a study case modified from the first IEEE SSR benchmark system is calculated, and it is shown when TCSC is operated in constant firing angle control, the possibility of SSO problem caused by TCSC can not be ruled out.