overvoltage caused by winding terminal arrangement of three phase transformer

usually both ends of a transformer winding are at the same side of the magnetic core. with this arrangement there are automaticaly the same number of the turns for each winding in both core windows next to the middle leg of a three phase three leg core type transformer. contrary to this arrangement it is possible to put the two ends of a winding at the different sides of the core. in this case the same number of turns in 'the both core windows corresponding to the windings on the middle leg does not exist. it means the amperturn of the windings of the middle leg can not compensate each other in both windows. if then the windings on the side legs be left free i.e. not connected to a load or to a source, a strong magnetic flux flows through both side legs, whichare in opposite direction to each others, and an overvoltage would be induced in the windings on the side legs. this can takplace during a shortcircuit, or through inrush current or load. in the paper above problem is discussed. the overvoltages caused by this phenomena through a sudden one phase short circuit of a three phase power transformer and the oscillation of the overvoltage caused by saturation of the core are calculated and compared with the measurement.