Effect of antioxidants on inception of electrical trees in polyethylene

Several PE and XLPE (cross-linked polyethylene) compounds containing different combinations of antioxidants were investigated. Treeing inception voltage was measured using a slow ramp stress of power frequency. The evaluated results refer to an interaction between different types of antioxidants. Some combinations were proved to be advantageous. However, combinations with antagonistic effects were also found. It is concluded that, by means of systematic investigations, combinations of antioxidants can be screened which are able to improve the resistance of PE and XLPE compounds both to electric and thermal aging. The enhanced resistance to electrical deterioration thus achieved provides a good start for further stabilization of insulating materials intended for EHV applications