Instability Detection and Prevention in Smart Grids Under Asymmetric Faults

Due to their unbalanced nature, asymmetrical faults usually have an adverse impact on power systems in comparison with symmetrical faults. In this article, we propose a methodology to detect and prevent instability due to asymmetrical faults based on multiple intervals in renewable integrated power grids (RIPGs). The proposed technique uses stability indicators, which are determined in real time to define a criterion for asymmetrical faults based on multiple intervals in RIPGs. Sensitivities related to these stability indicators are then determined to identify the most influential critical nodes for suitable countermeasure applications in RIPGs. To enhance the processing speed, a power system network evaluates only those critical nodes which are detected through a self-propagation graph, thus rooting the network operators straight to a vulnerable generator. For optimal assessment of the proposed countermeasures, such as operating of spinning reserves, a detailed stability analysis is performed. The proposed methodology detects critical nodes with high accuracy and also provides suitable countermeasures to prevent a large RIPG from the effects of asymmetrical faults.