Transient Characteristics of Negative Sequence Suppression in Offshore Wind Power Integrated via VSC-HVDC

The offshore AC system is a passive system without any synchronous power supply. The offshore converter station provides a stable voltage and frequency source for the system. Both ends of the system are power electronic converters with different negative-sequence suppression (NSS) strategies, which significantly influence the transient response characteristics at the point of common coupling and the convergence bus of wind farms. Thus, the fault characteristics and fault ride-through characteristics of the offshore AC system are determined by the control modes and negative-sequence suppressions. A real-time-digital-simulation platform of offshore wind power integrated via VSC-HVDC system is constructed according to the actual topology and parameters of Rudong project. Based on the platform, the configuration program and control objectives of existing NSS strategies are explicated. The influences of NSS on fault characteristics and fault ride-through characteristics are revealed.