Coordinated Synchronous Condensers and Static Var Generator Planning Considering Unit Commitment-Dependent Multiple Renewable Energy Station Short-Circuit Ratio Constraints

Ensuring adequate voltage support capability is a key challenge in planning power systems with large-scale renewable integration. This paper proposes a coordinated planning approach for synchronous condensers (SCs) and static var generators (SVGs) that accounts for unit commitment (UC)-dependent multiple renewable energy station short-circuit ratio (MRSCR) constraints. A UC–SC–SVG model is formulated to jointly determine SC and SVG siting and sizing, coordinating the short-circuit support of SCs with the reactive power regulation of SVGs. An impedance-aware graph residual network (IAGRN) is then developed to learn the nonlinear MRSCR residuals not captured by the first-order UC–SC physical model. Boundary-focused training and one-sided safety calibration are introduced to reduce the risk of misclassifying unsafe operating states as secure. The calibrated ReLU network is then converted into an equivalent mixed-integer linear representation and embedded in the planning model. Case studies on a provincial aggregated power system show that the proposed approach satisfies the MRSCR requirement across the representative operating states while achieving an economical allocation of SC and SVG capacity. Exact MRSCR post-checks and transient simulations further support the effectiveness of the embedded constraints and the voltage recovery performance of the resulting planning scheme.