Enhanced Control Strategies Temporal Coordination Based on Transmitted Active and Reactive Power during Commutation Failure Recovery

ABSTRACT The LCC‐HVDC inverter‐side control system adjusts control objectives and strategies during commutation failure recovery. Poor control strategies, temporal coordination, including improper engagement moment and duration, compromise control dynamic effects. The existing strategies selection method is limited in complex operations, posing a subsequent commutation failure (SCF) risk due to improper constant extinction angle control (CEAC) engagement. This paper employs transmitted active and reactive power as a unified indicator to select appropriate control strategies. Analysis reveals that an increase in transmitted active power reduces either transmitted reactive power or the extinction angle. High active and reactive power simultaneously lowers the extinction angle, raising SCF risk. Accordingly, an adaptive CEAC engagement method based on transmitted power is proposed to regulate the extinction angle earlier and prevent SCF. A reference power factor angle is constructed to represent the active‐reactive power ratio, from which a critical AC voltage is derived. By comparing the critical voltage and the actual AC voltage, an SCF warning is generated and a CEAC engagement criterion is proposed. The method is implemented for three major control systems (CIGRE, Siemens and ABB) according to their control structures. Simulations confirm that the proposed method effectively suppresses SCF under diverse control systems and fault scenarios.