Stability and Interaction Analysis of PMSG-based Wind Farms Connected with LCC-HVDC

The small-signal stability of a system connected with wind turbines (WTs) and line-commutated converter based high voltage direct current (LCC-HVDC) is a significant problem. Meanwhile, interactions among LCC-HVDC and WTs are considered to be the key factors leading to the instability. This paper analyzes the interactions among 2 permanent-magnet-synchronous-generator (PMSG)-based WTs and LCC-HVDC utilizing the interaction quantification method based on the self-stabilizing and en-stabilizing functions. By carefully considering the particular characteristics of the current source converter of LCC-HVDC, this paper proposes a small-signal model of such a system and calculates the transfer functions reflecting different interactions among different devices. Two case studies are presented to show different effect of the interactions and the control parameters on the system stability.