  To find a viable alternative to SF6 with growing climate change regulations,
proper evaluation of alternatives such as compressed air ought to be done. For
medium voltage applications, the withstand voltage is used as the dimensioning
criteria and this is dependent on the initiation and propagation of streamers
which are precursors to electrical breakdown. For design optimization, a
thorough understanding of the initiation and propagation mechanisms of such
electrical discharges under different stresses, pressure etc. ought to be
studied experimentally and numerically also via a predictive model. Most of the
numerical studies have so far been done via homemade codes as streamer models
are not readily available in commercial software because of the complexity and
non-linearity of such computations. Recently, with the increased robustness of
the plasma module of the commercial finite element software, COMSOL(tm)
Multiphysics, streamer discharge models can be developed with reasonable
accuracy. In this paper, an implementation and validation approach is presented
for streamer evolution in air for different voltage stresses. Results of
simulations for short gaps ($\le$ 5 mm) under Standard Temperature and Pressure
(STP) conditions have been presented, analyzed and compared with some classical
papers to evaluate the suitability of such a model for further studies of
non-thermal electrical discharges. Index Terms-medium voltage, streamer
discharges, eco-friendly gas, numerical models.
