This paper explores the behavior of moisture discharge voltages across various types of high-voltage insulators, with a focus on improving the reliability of external insulation in power systems. The study examines key factors influencing insulator performance, including contamination, atmospheric conditions, dielectric material properties, and the regulation of electric fields. External insulation, primarily composed of porcelain, glass, and polymer materials, is subject to environmental stresses that can lower its electrical strength. Moisture and contaminants on the surface of insulators significantly reduce discharge voltage, particularly in inhomogeneous electric fields, leading to potential failures. The analysis covers the distinct characteristics of dry, wet, and contaminated insulator surfaces, emphasizing how moisture and surface impurities form conductive films that lower discharge thresholds. This behavior is critical in high-voltage systems, where atmospheric influences like rain, humidity, and temperature play a pivotal role in the overall performance of insulation. Additionally, the study details how electric fields near insulator surfaces are managed to prevent corona discharges and surface arcs, which can degrade the insulation over time. Furthermore, the development of an automated calculation tool is highlighted, providing a more efficient and accurate method for predicting moisture discharge voltages across different insulator designs. By integrating both empirical data and theoretical models, the tool offers valuable insights for optimizing insulator performance under various environmental conditions, ultimately enhancing the reliability of power transmission systems.