Aspects of grid-connected converters and their inherent influence on the power grid

Abstract

Conventional power plants can be roughly unified with respect to the operational behavior of the synchronous machine (SM). Independent of the operation state, the machine’s operation can accurately be described with fundamental mathematical approaches. In a big contrast, such mathematical formulations are not suitable for converter-based generation units. In dependency of applied converter control strategies, hardware and control algorithms, the converter’s operational behavior can vary on a broad spectrum. In order to incorporate renewable energy sources (RES) like wind or photovoltaic into the electric power grid, converters are necessary. Therefore, the integration of RES into the electric grid leads to large-scale operational changes for grid operators. Changes in the electric power grid can especially be observed while considering system inertia or stability, short circuit characteristics and power system protection.