High-voltage direct current (HVDC) transmission systems connecting large renewable energy installations in remote Desert-Gobi-Wasteland regions exhibit weak-grid characteristics that destabilize conventional power control strategies. Low system inertia, insufficient damping, and reduced short-circuit ratios create pronounced coupling between active power changes and voltage fluctuations, making existing control methods inadequate for safe operation.
Researchers addressed this challenge by developing an integrated real-time active power control approach that simultaneously respects voltage security limits and maximizes the effective regulation capacity of diverse energy resources. The methodology begins by analyzing how strong active power–voltage interactions emerge in weak HVDC systems and uses sensitivity indices to quantify coupling strength across different operating scenarios.
A novel voltage weak-point identification technique leverages probabilistic power flow analysis to account for renewable energy output uncertainty. Combined with the impedance modulus margin indicator, this approach pinpoints locations most vulnerable to voltage instability. The researchers then quantified how wind power, photovoltaic systems, and HVDC controls affect these critical voltage nodes, establishing regulation space boundaries that maintain security.
The resulting control strategy integrates voltage-active power sensitivity data with resource regulation capabilities, implementing prioritized resource dispatch that meets active power requirements while minimizing voltage degradation. The approach differentiates how various resource types contribute to frequency regulation and voltage support, optimizing their combined effect.
Validation using modified IEEE 30-bus and 57-bus test systems confirmed the method's effectiveness in maintaining voltage stability while efficiently utilizing renewable generation. This work addresses a growing operational challenge as renewable-heavy systems, particularly in geographically remote regions, struggle with traditional frequency and voltage support mechanisms. The technique enables grid operators to safely dispatch larger volumes of intermittent renewable power from weak connection points while preserving system stability margins.
