The modeling and analysis of parallel distribution lines

It is fairly common in a distribution system to find instances where distribution lines are "physically" parallel. The parallel combination may have both distribution lines constructed on the same pole or the two lines may run in parallel on separate poles but on the same right-of-way. For example, two different feeders leaving a substation may share a common pole or right-of-way before they branch out to their own service area. It is also possible that two feeders may converge and run in parallel until again they branch out into their own services areas. The lines could also be underground circuits sharing a common trench. In all of the cases the question becomes how should the parallel lines be modeled and analyzed? The purpose of this paper is to develop the models for the parallel lines and demonstrate how they can be analyzed using the new models.