The Coordination Control for SSO Restrain in Multi-HVDC Transmission System

More attentions have been paid to subsynchronous oscillation(SSO) caused by HVDC transmission system in these years. Subsynchronous damping contraller (SSDC) is the main restrain scheme utilized widely. The coordination control of SSDC was investigated, in the background of the alternative-direct transmission power system of Guizhou province. Three conclusions were verified by both theoretical analysis and numerical simulations. Firstly, the SSDC and subsynchronous excitation damping controller(SEDC) are decoupled and can be set respectively in the SSO restrain. Secondly, the coordination control of SSDC in different converter stations are necessary. At the same time, the generator speed can be applied as the input signal for an effective restrain with the rapid development of communication technology.