Current distribution in paired-phase bus bars under unbalanced load conditions

THE operating characteristics of feeder systems for the distribution of large polyphase currents at low voltage are usually given on the basis of performance when conducting balanced steady-state currents. Voltage drops and temperature rise are measured, and impedance calculated, from simple tests involving the passage of balanced polyphase currents through one or more sections of the feeder duct having a wye tie at the end of the last section. The results are averaged and used to describe the rating of the system.