A three phase four wire feeder is connected at the substation in what configuration?

A three-phase four-wire feeder is commonly connected in a wye configuration at the substation. This configuration is used because it provides a neutral point, which allows for a balanced load across the three phases, while also enabling the use of single-phase loads without disrupting the balance. The wye configuration allows for higher voltage and greater flexibility in distribution, as it can accommodate both three-phase and single-phase systems. The presence of a neutral wire is essential for distributing power safely and efficiently, particularly in residential or commercial applications where single-phase loads are necessary.

In contrast, a delta connection does not include a neutral wire and is primarily used for three-phase loads. Series and parallel configurations are not typically used for feeding power at substations; they pertain more to the arrangement of components within an electrical circuit rather than the configuration of three-phase systems. Thus, the wye configuration stands out as the most appropriate choice for a three-phase four-wire feeder connected at the substation.