Analysis Of Svc'S Impact On Out-Of-Step Oscillation Based On Direct Method Considering Admittance Effect

The widely employment of power electronic equipment in modern power system, may affect grid structure and system operation because of their diverse dynamic characteristics. In this paper, the impact of the static var compensators (SVC) on out-of-step oscillation is investigated based on the equal area criterion by considering SVC's admittance effect. Firstly, the variation pattern of bus voltage which is connected to SVC is concluded. Then the derivation of equation considering the admittance effect is given, which explains the ability of SVC to suppress out-of-step oscillation. SVC's impact on migration of out-of-step oscillation centre (OSOC) is discussed based on the expression of OSOC's electrical location. Moreover, the influence of SVC's response speed and capacity on its effect are presented by qualitative analysis. Finally, simulations on a two-end equivalent test system are carried out to verify the correctness of the theoretical analysis. It is found that the capacity and a response speed of SVC have significant effect on the out-of-step oscillation, while SVC have no distinct influence on location of OSOC.