Voltage stability analysis using quadratic objective function taking into account inequality constraints

The author group proposes algorithm based on the analysis of the objective function consisting of the squared residual sum of node voltage equations to evaluate the closest maximum loading condition. The paper presents the development of research connected with consideration of inequality constraints, namely generators reactive power ranges. These constraints are taken into account by the usage of modified objective function supplemented by penalty components. Test calculations were made on the basis the simplest models and of 7- node power system. The proposed objective function and algorithm of the closest maximum loading condition calculation allows to identify power system security margin with set accuracy.