Analysis of Short-circuit Current Characteristics of Wind Farm with MMC-HVDC Transmission System under Symmetrical Fault

With the development of offshore wind power, wind farm with MMC-HVDC transmission system has received more and more attention. Due to the control effect of power electronics, the short-circuit current characteristics of the sending system are significantly different from those of the traditional power grid. In this article, considering the control strategy of wind farm and the control coupling effect, the short-circuit current characteristics under symmetrical fault at sending system are analyzed in detail. In addition, considering the existence condition of the stable equilibrium point of the system, the current amplitude constraint for the stable operation of the wind farm is derived. Finally, the correctness of current characteristic analysis is verified by time domain simulation.