Space charge dynamics of acetophenone and cumyl alcohol and their synergistic effect in LDPE

Acetophenone and cumyl alcohol, main crosslinking byproducts, will accelerate the loss of insulation life of the polyethylene-insulated high-voltage direct current (HVDC) cables. In this paper, the individual and mutual effects of these two byproducts on the space charge dynamics of low density polyethylene (LDPE) were studied by space charge measurement, and an interaction model was further proposed to explain their mutual effects. The space charge patterns were measured below 10 kV/mm to minimize the interference of the injected charge from the electrode. For the individual effect, the dissociation threshold of byproducts with electric field applied was investigated to determine the electric field where space charge begin to accumulate, combined with conductivity measurement as a further indicator. For their mutual effect, the interaction model was established based on the experimental results. Particularly, a synergistic effect was discovered in the coexistence system.