Model validation for voltage dip assessment in future networks

Energy transition will result in a generation shift from synchronous generation to renewable energy sources. Inverter-based renewable energy sources (IBRs) will supply a massive share of electrical energy. Unlike conventional synchronous generations, IBRs have a limited short-circuit contribution during faults. The lower short-circuit contribution from the generation side can lead to lower voltage support and hence deeper voltage dips during faults in the grids. Moreover, this possible reduction in the short-circuit power and system strength may also enlarge the propagation area and reduce the residual voltages during voltage dips; thus, connected parties may face more frequent severe voltage dips.

An important question to be answered is “how to quantify the impact of the generation shift combined with other changes in future grids because of the energy transition on the voltage quality, particularly the voltage dips.”

A validated model of the existing system is essential to investigate the energy transition impacts on the voltage dips in the future grid. This paper presents a practical model validation approach for voltage dip assessments. The proposed methodology is applied to the Dutch high voltage, extra-high voltage grids and the propagation to medium voltage grids. The model validity is investigated via data from power quality monitors for three severe voltage dip events in the Dutch grid. These events have been selected by a screening method that analyzed three years of voltage dips records. Finally, a sensitivity analysis investigates the possible origins of the mismatch between the model-based simulations and measurements. The proposed methodology and assumptions of this research can be applied to other power systems to check the validity of the models for voltage dip assessment.