A Performance Evaluation of SO_2 Gas and SO_2/CO_2 Gas Mixture as Potential SF_6 Gas Alternatives in Power Transmission and Distribution System

摘要

SF_6 gas free power transmission and distribution is need of hour. In this connection, we have evaluated the insulating performance of SO_2 and SO_2/CO_2 gas mixture based on parameter like drift velocity and effective ionization coefficients. These parameters are calculated using BOLSIG+ tool for SO_2, SF_6, N_2, and CO_2 gases as well as binary mixtures like SF_6, N_2, and SF_6/N_2 and compared with experimentally reported data for these gases. The following conclusion is made in this study. 1.SO_2 and SO_2/CO_2 gas mixtures have comparable insulating performance with respect to SF_6 and SF_6/N_2 gas mixture. The effective ionization coefficient of SO_2/CO_2 gas mixtures is lower by 30-35% of SF_6/N_2 gas mixture. Since these values are density and pressure dependent, better values can be obtained with increased density and pressure. 2.The drift velocity of SO_2/CO_2 gas mixtures is higher by 15-20% of SF_6/N_2 gas mixture, since drift velocity is depended to elastic and inelastic momentum transfer collision cross section. With availability of sufficient cross section database, better values of drift velocity may be obtained. 3.BOLSIG+ is useful tool to calculate swarm parameters which are required for study of various gas physical process like streamer discharge, corona discharge. The values calculated are in close agreement with experimentally reported values. Other aspects of any SF_6 gas alternative require further work toward understanding of gas discharge process like behavior in non-uniform electric field, streamer discharge, and corona discharge as well as chemical stability during discharge at high pressure and temperate for SO_2 and SO_2/CO_2 gas mixtures.