Remote feeder transfer between out-of-phase sources using STS

To insure reliability in electrical networks, loads are supplied by more than one source. In this paper a transfer scheme using two Static Transfer Switches (STS) located remotely is presented for transferring the feeder load to an alternate source that is out of phase from the primary (preferred source). The objective is to have a minimum disruption to the feeder voltage in terms of the dead time for transfer appearing as notches in the voltage waveform. The new proposed transfer method requires only a minimum communication between the two STS units in order to achieve synchronization. Different case studies of transferring power in a typical network while two sources having a phase difference are simulated and presented in this paper using MATLAB/SIMULINK.