Study on Creepage Dielectric Insulation under Combined Salt Pollution, High Humidity and Transient Air Pressure

In recent years, electrical equipment is being installed not only in conventional electric rooms at factories, but also in harsh environments such as underground, high-altitude regions, sea (off-shore or vessel applications), and aircraft. Therefore, it is necessary to understand the electrical insulation characteristics against combined environmental stresses. In this study, we have evaluated the characteristics of creepage insulation, especially in combination with different voltage, salt pollution, humidity, and transient air pressure conditions. As a result, we have developed a new test system that reproduces these aforementioned combined environmental stresses. Moreover, we have derived empirical flashover voltage prediction formulas for creepage insulation design using each stress element as a parameter. Using this, we will be able to improve the insulation reliability of electrical equipment for our product.