Dynamic Voltage Stability Assessment of an Electric Power Network using Composite Load Models

Electric power network stability analysis requires that all system components are represented by their models. Usually, detailed data about system components such as generators, transformers and transmission lines are available. In this case accurate models can be derived from the network devices. However, corresponding data for individual loads are not always available, which makes the modelling of loads an important area of research studies. In this paper it is studied and analysed the effect of the composite load models in the dynamic voltage stability of an electric power network. The composite load models comprise residential, commercial and industrial loads. A severe contingency situation was simulated. The automatic voltage regulators of the generating units, the turbine speed governors, and the under load tap changers models were taken into account. The simulation results were obtained using the EUROSTAG software package. Finally, some conclusions that provide a better understanding of the dynamic voltage stability are pointed out.