Mechanized Calculation of Unbalanced Load Flow on Radial Distribution Circuits

This paper describes a computerized method of calculating unbalanced load flow or fault currents on multi-grounded radial distribution circuits. It was developed by engineers of the Baltimore Gas and Electric Company, and is now being used in operating and expanding their distribution system. The basic concept employed is that the electrical characteristics of any portion of an unbalanced 3-phase circuit can be represented by a 6-element wye-delta network. An operating program that can accommodate up to 750 circuit branches has been written for the IBM 7094 computer.