Analysis and research on the influence of multiple factors on the steady operation area of large-capacity MMC-HVDC transmission system

Abstract

Aiming at the MMC-HVDC (modular multilevel converter based high voltage direct current), this paper studies the influence of multiple factors such as the AC system and converter characteristic limits on the steady-state operating range of the MMC-HVDC transmission system. First, a mathematical model based on the steady-state operation of the MMC-HVDC transmission system is established, and the AC-side power quality requirements and stability limiting factors of the MMC-HVDC system are analyzed and summarized, as well as the constraints of multiple limiting factors on the converter side. Based on this, the power operation range of MMC-HVDC transmission project under different conditions is obtained. Finally, combined with the actual project, the effects of modulation ratio, equivalent reactance between the AC outlets of the converter and AC system equivalent impedance on the steady-state power operating range are analyzed and studied separately.