СИНТЕЗ ЛІНГВІСТИЧНИХ МОДЕЛЕЙ ДЛЯ ВІДТВОРЕННЯ ВПЛИВУ БЛИСКАВКИ НА ЧАСТОТУ ВІДМОВ ЕКРАНУВАННЯ ПОВІТРЯНОЇ ЛІНІЇ ЕЛЕКТРОПЕРЕДАВАННЯ

Background. Traditional methods for calculating lightning protection systems are continuously improving based on new knowledge about lightning and its characteristics. Growing demands for protection efficiency, especially for power transmission lines in the Smart Grid concept, create a need for new approaches. Fuzzy logic serves as one way to address these challenges, as it allows modeling complex and uncertain processes, which are typical for lightning protection systems. Objective. The main goal is to develop a linguistic model for predicting the failure frequency of shielding based on lightning current parameters, the width of the failure zone, and the current probability density function. Simulation helps calculate failure frequencies that could lead to insulation flashovers and equipment damage. Methods. An electrogeometric model was used to determine the width of the shielding failure zone. The synthesis of linguistic models for replicating the effect of lightning on the shielding failure rate was performed using a mathematical apparatus of fuzzy logic. The shielding failure rate is considered, which determines the probability that lightning will strike the phase conductor, bypassing the overhead shield wire. It is assumed that the minimum current for calculations is 3.0 kA, which is the threshold below which no initial lightning strikes have been observed on real power transmission lines. The probability of such a lightning current is calculated to be only 0.23%. For modeling the lightning current probability density function, formulas similar to the results of measurements on research towers were used. Results. A data about the width of the lightning shielding failure zone on a typical 330 kV power transmission line tower is obtained, demonstrating how this zone changes with different prospective lightning current values. Conclusions. Simulating the failure frequency of shielding using fuzzy logic and the Mamdani algorithm allows for more accurate failure predictions, taking into account variable conditions. Structural diagrams and transfer functions demonstrate how different parameters, such as current, current density, and failure zone width, affect the failure frequency. All these parameters and their interrelationships are described using linguistic variables and fuzzy rules, enabling more effective predictions for lightning protection systems. This approach provides more accurate and flexible modeling, meeting modern requirements for the safety of overhead power transmission lines, especially within the Smart Grid concept.