The characteristics and main causes of power system failures basing on the analysis of previous blackouts in the world

The major purpose of power system is to ensure continuous and infallible power supply. In the face of real threat of widespread power system failures which affected numerous power systems, there is a necessity of preparing projects for power system defense and restoration. The defense of power system considers the possibility of failure dodging and, in the case of its occurrence, the limitation of failure range and consequently, return to normal conditions. In turn, successful restoration of power system is connected with generation capacity reconstruction and in the result, power supply of the final consignees. The imminence of power system failures stems from its various triggers, such as atmospheric phenomena, human factors and technical malfunctions thus widespread catastrophic failures of power system constitute a real threat not only to electrical power system, but also to widely understood safety. The development of system failure is a cascading process that is highly sensitive to disturbances in the performance of the power system. The paper contains a review with a statistical analysis of recent large power system failures with particular attention to major blackout causes. The paper also delineates cascading nature of power system failures by indicating the failure stages on the examples of the large blackouts in power systems.