An Improved Control Strategy Study for “Strong HVDC and Weak AC“ Receiving-end Grid under Continuous Commutation Failure

The commission of QINGYU HVDC brings a large amount of clean power to Henan province, which increases the flexibility of the system operation and the complexity of the ACDC system operation. The strong HVDC and weak AC contradiction of the power grid is prominent, which is prone to commutation failure and threatens the safe and stable operation of the power grid. Aiming at continuous commutation failure of “strong HVDC and weak AC” receiving-end system, the paper analyzes the mechanism of commutation failure and the influence of control strategy on transient characteristics of multi-fed DC system, and proposes an improved VDCOL control strategy to effectively reduce the probability of continuous commutation failure and improve the recovery speed.