Static var compensator （SVC） devices can effectively prevent the voltage collapse of a power system, because of its characteristics of quickness and flexibility. Since the model analysis using the Jpo in the Jacobi submatrix considers the effects on voltage stability of both active load and reactive load, it is superior to the V-Q sensitivity analysis in terms of mathematical theory. Furthermore, the participation factor figure by virtue of the modal analysis method is able to establish the relationship among nodes of network topology and improve the influence degree of the crisis modal, and therefore the modal analysis is widely used in the allocation of SVCs. In the recently years, many researchers have tried to build the second order analysis method of modal analysis.