Digital calculation of transmission line impedances

TWO PROGRAMS for the IBM 650 digital computer have been developed by the Detroit Edison Company for computing the symmetrical component impedances of 3-phase 60-cycle open-wire transmission lines. One program obtains the data for a complete line with due consideration for any changes in configuration from tower to tower; the other obtains the data, on a “per mile” basis, for a fixed configuration. Fig. 1 is a block diagram of the “per mile” program. Limitations on the programs are: 1. Lines are assumed to be fully transposed. 2. Towers carry no more than two circuits. 3. Each circuit has only one conductor per phase. 4. Each tower may have no ground wires, one ground wire, or two identical ground wires