부산대학교 도서관

The Flexible Low Frequency Transmission System (FLFTS) has more complex coordination control mechanism and fault transient process. In this paper, the control architecture of the flexible low-frequency converter station is analyzed firstly. Based on the basic control principle of power electronic converter station, a fault ride-through strategy suitable for the FLFTS is proposed. When a fault occurs in the low-frequency line, the system detects a sudden drop in low-frequency voltage. After a short delay, the control pattern switching module of the converter station switches the low-frequency side control to the direct current control, and the low-frequency current re-tracks the preset current limiting target to achieve the goal of active current limiting fault ride-through. A two-terminal low-frequency transmission system model is built on the PSCAD/EMTDC simulation platform to verify the effectiveness of the ride-through method. Finally, based on the simulation model, taking into account the fault ride-through control of the converter station, the impedance characteristics of the equivalent low-frequency variation of the FLFTS under different current limiting targets are analyzed, and the influence on the original protection is discussed.