Coordinated preventive control strategy for transient overvoltage suppression in hybrid AC/DC sending-side systems

As a predominant issue within line-commutated converters-based high voltage direct current (DC) transmission systems, commutation failure may trigger transient overvoltage problems and the tripping of large-scale renewable generation sets in hybrid AC/DC sending-side systems. Analyzing the impact of DC faults on the power system and implementing effective preventive control measures have become crucial tasks for power industries. In this paper, integrating a model-driven scheme, decision tree (DT) model is utilized to predict the overvoltage peak values of alternating current (AC) buses in the DC vicinity, unveiling the correlation between electrical quantities of power grids and transient overvoltage. Moreover, the conventional DT algorithm is enhanced by adjusting the error weight allocation, enhancing the adaptability of prediction model to high-risk scenarios. Based on the improved integrated model, the preventive control sensitivity index is established to quantitatively evaluate the effectiveness of alternative control measures in suppressing transient overvoltage levels, and the optimal preventive control strategy is formulated to coordinate multiple controllable resources for transient overvoltage, guaranteeing the reliable operation of power systems. Case studies were performed in a simplified simulation system of local area power grids with transient overvoltage issues, and results validated that the proposed preventive control strategy can eliminate the risk of power system transient overvoltage.