Enhancing the utilization of the matlala and glencowie 22kV radial feeders by interconnecting them using a phase shifting transformer

The lines that supply customers are usually of radial topology, and their backbones are built at medium voltages (usually 11kV and 22kV). The loading of the main backbones of such lines are influenced by the total size, in MVA, of the customers connected to the lines. These lines generally are not connected to other lines. Sometimes, interconnectors between such lines are created so that if one line experiences constraints such as violation limits for voltage and thermal loadings, some of the load can be relocated to the other, nearby feeder so that constraints on the first feeder can be eased. Here, a consideration of connecting these types of radial feeders using a phase shifting transformer is made. In this paper, it is shown that if one feeder is experiencing load-flow constraints, such as undervoltage or thermal overload, a phase shifting transformer can be used to restrict power flowing in this feeder, forcing some of the power required by its load to be channeled via the backbone of the healthy, radial feeder. In this way, constraints on the unhealthy feeder can be eased.