The incorporation of space charge degradation in the life model for electrical insulating materials

The time function of the Eyring reaction rate theory of insulation life is modified to demonstrate a physical origin for temperature threshold. Various mechanisms by which trapped charges may be involved in degrading the polymer are examined, and incorporated into the life model through an alteration to the free energies of the reacting system. The corresponding life functions are shown to possess the field-dependent threshold form previously obtained phenomenologically for insulating materials. The physical interpretation of the model parameters is discussed.