Evaluating the Suitability of a Thévenin Grid Model for Large-Scale Power Systems in Germany

In the light of the German energy transition, maintaining system security becomes more challenging since the number and severity of critical system operation points will increase. This is due to volatile power infeed from renewable energy sources (RES), higher grid loads, and the phase-out of conventional power plants. As RES, to be equipped with reactive power management systems, will be mainly installed in sub transmission to low voltage level, voltage control strategies at the grid connection points between transmission and distributions system operator must be overthought. One aspect is the analysis of quasi-dynamic voltage changes when switching tertiary reactors in a 380/110 kV substation. In this paper, a model of the electrical environment of the substation based on Thévenin equivalents is developed and evaluated with respect to functionality. Based on the results, the paper provides further steps to be taken to integrate the model in system operation planning processes.