Determination of the Voltage Stability Index in DC Networks with CPLs: A GAMS Implementation

This paper addresses the voltage collapse analysis in direct-current (DC) power grids via nonlinear optimization approach. The formulation of this problem corresponds to an optimization problem, where the objective function is the maximization of the loadability consumption at all the constant power loads, subject to the conventional power flow balance equations. To solve this nonlinear non-convex optimization problem a large-scale nonlinear optimization package known as General Algebraic Modeling System (GAMS) is employed. Different nonlinear solvers available in GAMS are used to confirm that the optimal solution has been reached. A small 4-node test system is used to illustrate the GAMS implementation. Finally, two test systems with 21 and 33 nodes respectively, are used for simulation purposes in order to confirm both the effectiveness and robustness of the nonlinear model, and the proposed GAMS solution methodology.