Breakdown and pre-breakdown characteristics of mixed liquid dielectrics and the effect of magnetic field on them

Breakdown and pre-breakdown studies of liquid dielectrics have been the topics of considerable studies and research for the long time. From Whitehead onward considerable studies have been made and several theories have been put forward by researchers, but there is no generalized theory developed so far. In this paper breakdown and pre-breakdown behaviour of mixed liquid dielectrics such as transformer oil (mineral oil) and castor oil, linseed oil and castor oil and mineral oil and linseed oil have been investigated, which have not been reported so far in the available literatures. Further, the effect of magnetic field on the breakdown characteristics of all the mixed liquid dielectrics as stated have been studied. It has been observed that the effect of cross magnetic field increases the breakdown strength to some extent in all the mixed liquid dielectrics used for the experiment. It has been further observed that an axial magnetic field has no effect on the change in the breakdown strength. It may be stated that during the time of breakdown of liquid dielectric, gaseous phase is present. At the time of breakdown under the influence of cross magnetic field, electrons, instead of moving in straight line between collisions are deflected as a result of which there is an increase in collision frequency resulting in decrease of electron mean free path which in turn increases the breakdown strength in all the mixed liquid dielectrics used for the experiment