Research on multiple Svcs allocation method considering operation mode changing

Taking operation mode changing and combined influence of multiple SVCs on power system into account, a multiple SVCs allocation method is proposed in this paper. This method is presented through normal form analysis, and based on the information provided by second-order analytical solution of perturbation equation. This method includes three steps: Firstly, the most critical operation mode, which is the closest to voltage collapse of the system, should be determined based on static voltage stability analysis. Secondly, in this critical mode, the small signal stability analysis should be made on the perturbation equation of certain power system, and then analytical solutions of all the PQ buses could be obtained by using normal form. Finally, using first-order and second-order oscillation amplitudes of the second-order analytic solutions, the multiple SVCs locations can be determined, with an index of reducing perturbation amplitudes. Comparing to those methods which do not consider the influences of multiple SVCs, the proposed method has a better performance on static voltage stability margins expanding. The IEEE 30-bus power system will be used to prove the effectiveness of this method.