Hybrid commutation converters (HCCs) utilizing reverse-blocking integrated gate commutation thyristors (IGCTs) have gained significant attention due to their immunity to commutation failure. Leveraging the recovery enhancement characteristics of IGCTs, HCCs demonstrate superior performance at reduced extinction angles, thereby minimizing reactive power consumption. This study presents a comprehensive investigation into reactive power control strategies for HCCs operating at small extinction angles. First, the topological configuration and commutation principle of HCC are elucidated. Subsequently, the mechanism of HCC reactive power control is analyzed, and a reactive power control strategy is proposed by combining the converter transformer taps with extinction angles. Moreover, the relationship between transformer taps and reactive power exchange under different rated extinction angles is calculated, and the theoretically rated extinction angle is proposed. Finally, to validate the proposed control strategy, a four-terminal ultra-high voltage direct current power grid incorporating HCC technology is modeled and simulated using PSCAD/EMTDC. The simulation results demonstrate that the proposed strategy effectively supports AC systems by reducing reactive power absorption in HCCs, while simultaneously exhibiting enhanced reliability and economic efficiency.