### Choice of Frequency for Very Long Lines

P. M. Lincoln
1903 Transactions of the American Institute of Electrical Engineers
Although other frequencies are in use in this country, there are only two which by the extent of their use can be called standard, viz.: 60 and 25 cycles per second. Without discussing the relative merits of other frequencies, the question now presented is, which is the better frequency for a very long line, 60 or 25 cycles per second, considered purely as a transmission problem. In the present state of the art, 200 miles may be considered ag very long for a transmission line. Although longer
more » ... . Although longer ones have been proposed, only one of this length has been put into actual operation and no other line approaches this length. The reasoning which follows will, therefore, be made to apply to a typical line 200 miles long. -Frequency has a direct bearing upon voltage regulation and charging current and its influence on a possible condition of resonance may also be profitably discussed. 1st. Voltage Rcgul tion.-The difference between the voltage at the transmitting and the receiving stations, termed the "drop," is dependent upon several elements, among which are the resistance and the inductance of the circuit. The volts for overcoming the resistance are the same as would be required for sending a direct current equal to the normal alternating current through the line, if it be short-circuited at the receiving end. The volts for overcoming the inductance at any frequency are measured by the pressure which would be required for sending the alternating current at that frequency through the short circuited line, if the ohmic resistance were negligible. The inductance volts are directly proportional to the frequency. The difference in voltage between the transmitting and receiv-373