فهرست نشریات علمی دسترسی آزاد ایران

Insulator strings are important and critical components of overhead lines, providing insulation properties and preventing leakage currents. This paper assesses the influence of several factors on the voltage distribution and leakage currents of insulator strings. Non-uniform voltage distribution among the units of an insulator can lead to degradation of the string and reduced reliability of the overhead lines and power network. In this study, a detailed analysis of five-unit porcelain and glass insulator strings under various conditions is conducted using circuit modeling and simulation in the MATLAB environment. The investigated scenarios include different levels of surface pollution, deviations of the insulator string toward or away from the tower, and the presence of a defective unit within the string. The results indicate that increasing pollution levels improves voltage distribution uniformity among the units, thereby enhancing the overall efficiency of the string; however, it also results in an increase in leakage current. Moreover, when the string is deflected outward (away from the tower) compared to inward deviation, a more uniform voltage distribution is achieved along with a notable reduction in leakage current. In the scenario involving a defective unit, the voltage stress on that unit decreases, and its voltage share is redistributed among the remaining healthy units depending on their relative positions. Simulations show that glass insulator strings exhibit a more uniform voltage distribution and higher efficiency compared to porcelain insulator strings under clean conditions and also under low to medium pollution levels.