Dual directional over-limit direct correction control of terminal voltage in medium-voltage distribution network based on SOP active–reactive power coordination

Terminal voltage bidirectional over-limit issues in medium-voltage distribution networks exhibit nonlinear characteristics, which complicate accurate detection and effective control. To address this, a direct correction control method based on the coordination of active and reactive power via Soft Open Point (SOP) is proposed. Using a power flow model derived from Kirchhoff’s current law, the node voltage magnitude is characterized. An objective function and constraints are established to minimize voltage-sensing deviation. Through global sensitivity analysis based on the Jacobian matrix, the influence of SOP regulation on the terminal voltage is evaluated, enabling the development of a coordinated active–reactive power control strategy. By dynamically adjusting the SOP output power ratio, voltage fluctuations are suppressed proactively. A correction control mechanism incorporating dynamic thresholds and multi-condition fusion is designed, along with adaptive over-limit judgment rules to enhance both sensitivity and stability. A hierarchical iterative strategy solved via parallel gradient descent achieves direct correction control for bidirectional voltage over limits. Test results demonstrate that the proposed method accurately tracks voltage fluctuation trends and reliably identifies upper- and lower-limit violations, providing a solid foundation for voltage control. Implementation yields reduced voltage fluctuations, improved correction performance, and significantly lower probability of node overvoltage incidents, thereby enhancing the distribution network’s power supply capacity.