PROJECT TITLE :

Impact of DC Breaker Systems on Multiterminal VSC-HVDC Stability

ABSTRACT:

The utilization of VSC-HVDC grids for offshore wind farm integration will require the employment of dc breaker systems and presently they require dc reactors to limit the speed of rise of fault current. The introduction of large dc reactors throughout a VSC-HVDC system can have a significant impact on its stable operation and will need further control. This paper analyzes this problem and proposes a PSS-like management (DCPSS) to assist dc grid stability and cope with this impact. A generalized analytical model for studies on dc voltage control is presented. Key stability and transient performance issues caused by the employment of the dc reactors during a multiterminal system are investigated by analyzing poles, zeros, and frequency responses of open-loop and closed-loop models. Design and location identification ways for the DCPSS are provided. An excellent damping enhancement is achieved by this controller. The analytical studies and time-domain simulations in this paper are performed based on 2 VSC-HVDC models.