Economic considerations of the power factor control of long high-voltage lines

In the early days of the electric industry when transmission lines were short, power factor control was not considered necessary. At the present time, with transmission lines of 200 miles and more, and with loads whose power factor is very poor owing to the universal use of the induction motor, power factor control is being forced upon the transmission engineer as a necessity if power is to be transmitted economically. By taking a few typical examples of transmission lines, the effect of power factor upon efficiency of transmission is shown very clearly. The most economical line power factor for any ordinary commercial transmission line is shown to vary by a comparatively small per cent and to be slightly less than unity. At the same time there appears a very wide range of load delivered over a line without an undue rise in cost of transmission.