SUMMARY
The object of research is the probabilistic characteristics of the occurrence of a short circuit (SC) on overhead electric transmission lines (ETL) of voltage classes 110 kV and higher, the failure of which can lead to the development of an accident in the electric power system (EPS). The probabilistic characteristics of the SC occurrence on ETL depend on a large number of factors: the length and route of transmission of power lines, voltage class, weather conditions, and the qualifications of the staff in which charge, management and maintenance the power lines are located. The most problematic issues in assessing the SC occurrence on overhead power lines is the allocation of damage from a SC with general damage statistics, the quantitative consideration of such features of the functioning of overhead ETLs, such as meteorological conditions, the staff qualification level and the technical condition of a single piece of equipment.In the course of the study, a fuzzy-statistical approach is developed to assess the SC occurrence on an overhead power line taking into account its individual characteristics of work, such as the staff qualification level, meteorological conditions of operation and the technical condition of the power line. To determine the unconditional probability of SC occurrence on an overhead ETL, statistical data on SC on lines of the corresponding voltage class are used. The technical condition of the power lines and meteorological conditions of operation are quantified by fuzzy models, the staff qualification level is determined at standard intervals of the Harrington scale. Conditional probabilities of the state of functioning of power lines are determined using a simplified fuzzy conclusion, which makes it possible to quantify the conditional probability in the absence of clear analytical relationships between the signs of the conditions of power lines.The results obtained by the developed approach are recommended to be used in the goals of risk-oriented management of the EPS to increase the reliability of operation by reducing the risk of developing a system accident when a SC occurs in the EPS elements. Also, restrictions on the application of the developed approach to the problems of assessing the probability of equipment failure and the organization of risk-based management are identified.