Unbalances of untransposed overhead lines

✍ Scribed by Eric T.B. Gross

• Publisher: Elsevier Science
• Year: 1952
• Tongue: English
• Weight: 697 KB
• Volume: 254
• Category: Article
• ISSN: 0016-0032
• DOI: 10.1016/0016-0032(52)90146-4

✦ Synopsis

Improvements in equipment and new developments in both the communication and power fields have greatly reduced the need for transpositions at close intervals on overhead high voltage lines. In many systems transpositions are now made only at switchyards and are kept to a minimum.

Geometric unbalance of untransposed high voltage lines leads to circulating residual ground currents in systems which are solidly grounded, to neutral voltages to ground in impedance and resonant grounded systems, and to negative sequence currents which flow also in transformers and generators.

Experience has been very satisfactory on systems in which line transpositions were eliminated; however, it is desirable to know the magnitudes of the unbalanced currents and voltages.

Practical methods for the computation of these residual and negative sequence quantities are summarized in this paper.