Application of Molecular Dynamics Study and Homo Lumo Calculation on the Ionized Air for High Voltage Engineering

Air is a gas insulation in high voltage engineering. Generally, the air content consisted of several gas elements like N 2 , CO 2 , CO, H 2 , CO, and O 2 . Sunlight can cause the air ionization, the air ionization can resulted because of the high electric fields and also the interaction between electrons from gas molecules. The air which ionized in the high voltage, leads to the event of isolation failure or better known as the failure process of Streamer and Townsend. The main purpose of this research was to get a better insight of air ionization process. Tools such as molecular dynamic and SCF calculation can be used to achieve this goal. For the CO 2 molecule, the best pose was selected at the time value of 1.000 s with the energy of 0.0502 kcal/mol, at temperature of 120.440 K and pressure of 1260386 barr. While the other gas, N 2 molecule, is seems to be stable under ionization process. Thus, for this molecule, the best pose was found at the time value of 1.000 s, energy of 0.0526 kcal/mol, with temperature of 205.949 K and pressure of 78539.601 barr. Based on the molecular dynamic results, O 2 molecule will be ionizes at time value of 1.000, energy of 0.430 kcal/mol, with temperature of 0.0104 K and pressure of 18498.320 barr. SCF calculation give the energy ionization potential value for N 2 , CO 2 , O 2 , H 2, N 2 and O 2 , CO 2 and O 2 , CO 2 N 2 and O 2 of 9.38 eV, 11.81 eV, 9.38 eV, 11.99 eV, 9.38 eV, 9.38 eV, 9.38 eV, respectively. Based on this calculation, the molecule with lowest potential ionization energy can ionized easier. N 2, NO 2 , N 2 gases and O 2 , CO 2 and O 2 , CO 2 , N 2 and O 2 are ionized easier than gas CO 2 and H 2 .