00:01
Hello, in the question we have to explain the different mechanism by which the breakdown occurs in the solid dielectric in practice.
00:12
So, the first one is the chemical and the electrochemical deterioration and breakdown.
00:20
So, now what we have written is in the presence of air and other gases some dielectric material undergo chemical changes when subjected to a continuous stresses.
00:36
Now the chemical so now what are the chemical deteriorations? so, the first one is the oxidation.
00:43
So, in the presence of oxygen so oxidation of that material can take place.
00:49
So, the materials like rubber or say polythene it can undergo oxidation and that will cause so it will give rise to the cracks in that material.
01:07
Then second one is hydrolysis.
01:09
Hydrolysis occurs when there is some water vapor or some moisture present on the surface of the dielectric.
01:17
So, now the hydrolysis will take place and the hydrolysis may when the occurs so that material will lose their electrical and the mechanical properties.
01:35
So, for example, so if we want to give the example so for example the electrical properties of materials such as paper then say some cellulose material they deteriorate very rapidly due to the hydrolysis due to the process of hydrolysis.
01:55
Now the next is the chemical action.
01:59
Now even in the absence of the electric field so there will there can be some progressive chemical degradation of the insulating materials.
02:09
So, now this can occur due to the instability some chemical instability at some high temperatures.
02:23
So, oxidation then cracking in the presence of air hydrolysis so this occurs and heat so it is due to the so this chemical action this occurs when even if the electric field is not there so even if the electric field is not there so chemical degradation takes place and it can take place at some higher temperatures.
02:54
So, this can happen...