Choosing the right transformer bushing requires considering key factors such as voltage level, current, operating environment, and insulation structure. It is generally recommended to prioritize selecting the main insulation type based on whether the rated voltage exceeds 40.5kV.
Selecting the Main Insulation Structure by Voltage Level
Voltage level is the fundamental condition for determining the type of bushing:
Rated voltage > 40.5kV: Capacitive bushing should be selected. Its main insulation consists of a capacitor core, achieved through alternating layers of insulating paper and aluminum foil, and impregnation with oil, resulting in a uniform electric field distribution. Suitable for high-voltage systems of 110kV and above.
Rated voltage ≤ 40.5kV: Pure porcelain or composite bushings can be selected. These have a simple structure and lower cost, suitable for distribution systems of 35kV and below.
