Analysis of AC Fault Ride-through Characteristics of the Baihetan-Jiangsu Hybrid Cascaded UHVDC System

The hybrid cascaded ultra-high voltage direct current (UHVDC) system is a system in which the rectifier station is composed of line commutated convertors (LCCs) and the inverter station is composed of an LCC in series with multiple modular multilevel converters (MMCs). The AC fault ride-through characteristics and corresponding influence factors of the Baihetan-Jiangsu hybrid cascaded UHVDC system are studied in this paper. Simulations are carried out from the aspects of the influence of AC faults on the UHVDC system, the influence of the MMC control mode and synchronous condensers on the fault-ride through characteristics. The results show that the dynamics of the inverter side LCC has little effect on the MMCs. The MMC control mode will affect the temporary overvoltage level of the MMCs, and the synchronous condenser can improve the fault ride-through characteristics of the UHVDC system in case of some faults.