When connecting two generators together (in parallel), there are conditions that must be met and fulfilled before commencing the electrical connection process, which are known as synchronization conditions. In this paper, the loss of equality voltages which is one of the synchronization conditions will be represented when performing the connection process using Matlab and surveying the impact of this on the performance of the system and the extent of damage that may result from it. The presented analysis shows the influence of faulty synchronization on the following physical quantities: internal voltage, stator current, stator voltage, angular mechanical speed, terminal voltages which are the most vulnerable. In addition, knowing the type of fault (short circuit fault) caused by the faulty synchronization condition. In this paper, over and under voltage schemes have been implemented by using MATLAB/SIMULINK.