It is at this stage of deterioration of the insulation system that massive destruction of the insulation occurs. T. W. Dakinl4 found that corona discharges are essentially a local limited breakdown the gas space. Direct infringement of corona discharges on insulation surfaces causes slow to rapid decomposition of all organic plastic materials. C. Mayoux, G. Garcia, and J. Sarlaboux15 dis- cussed corona effects on specific materials and their chemical trans- formation The time noted for transformation under the test conditions was 200 to 300 seconds. M. Goldman and R. S. Sigmond16 published a paper in 1982 regarding "Corona and Insulation This extensive paper covers many of the aspects of the corona insulation interaction.