In the simulation below there are 4 units of cap using comsol multyfisics softwa
ID: 2268737 • Letter: I
Question
In the simulation below there are 4 units of cap using comsol multyfisics software. It is showing effect on the divice. Therefore, the question is: and pin insulators and i did this simulation by the level of the electric field and how it will Are four units of cap and pin insulators enough to avoid flashover or not. Knowing that the break down of air begins at 3 kv/mm and level of electric field is showing in the second picture. My answer is yes that four units are enough because the electric field around the surface of these units does not reach 3 kv/mm (sky blue color) it just reach 1.5 kv/mm which means that the air will not break down. Please explain your answer and give more details to let me understand exactly why four units are enough or not and are there any cavities in these units or not. If yes tell where is it
Explanation / Answer
yes.. four units are enough to avoid flashover or dielectric breakdown between the insulators..it all depends on the level of voltage across the string of insulators and also the string efficiency is important here:
string effieciency = voltage across the string/ (no.of discs * voltage of the disc near the conductor it is carrying)
if we increase the voltage level the no.of discs used will be increases because there is change in the self capacitance which is bbetween the disc and the pole or tower and mutual capacitance between the discs.. if we increase the voltage with reduce number of the discs .. between the discs mutual capacitance increases and chance of dielectric breakdown ..so it all depends on voltage you applied across the string..the results you showed clearly says that the flashover never occurs with the gradient 1.5kv/mm as it is less than 3kv/mm. so four units are enough.