Enhancement of load flow computation methods to improve the convergence with automated measures based on stability analyses

Future scenarios of generation and load are predicted with market models which consider possible prices and demographic developments. However, nodal reactive powers which are critical in terms of the convergence of load flow calculations can only be estimated. The reactive power demand of heavily stressed power systems differs from regular burdened scenarios, whereby the estimation of the nodal reactive powers is complicated and minor differences affect the convergence characteristics of load flow calculations significantly. The algorithm that is presented in this paper modifies the reactive nodal powers during the load flow calculation if it does not converge. Regions of instability and measures for convergence achievement are determined with a modal stability analysis.