Insulators in high-voltage transmission systems play a vital role in maintaining power system reliability; however, their performance is strongly affected by environmental conditions, particularly industrial pollution such as cement dust. Exposure to such pollution can reduce insulation capability and increase the risk of electrical disturbances. This research was carried out in the High Voltage and Insulation Technology Laboratory using the solid layer method in accordance with IEC 60507. Samples of porcelain, glass, and polymer insulators were tested under clean
conditions and after being artificially contaminated with cement pollution. The main parameter analyzed was the breakdown voltage (flashover voltage) at various humidity levels, along with observations of physical changes on the insulator surface. The results show that cement pollution significantly reduces the breakdown voltage, especially under high humidity conditions. In addition, the insulator surfaces experienced visual degradation such as fine cracks and the formation of conductive layers that are difficult to remove. Compared to other types, polymer insulators demonstrated better performance against cement exposure than porcelain and glass insulators. These findings emphasize the importance of regular monitoring and maintenance of insulators in cement industry areas to ensure the reliability of highvoltage transmission systems.