CONSTRUCTION OF TRANSMISSION-LINE CATENARY FROM SURVEY DATA

Precise survey data from observations of actual overhead transmission lines are commonly used to confirm theoretical predictions of sag-tension calculations, based on the standard catenary model. An algorithm is presented for determining the catenary of best fit to a set of data points in the usual cartesian coordinates. The method described employs the least-squares criterion for curve fitting, and uses the iterative Newton-Raphson algorithm to solve for the required catenary parameters. A FORTRAN 77 subroutine implementation of the algorithm is used in a conductor profile program by the South East Queensland Electricity Board, and a PC version coded in Borland Pascal is available from the author. The program uses the subroutine to generate the equation of a transmission line catenary from survey data, thus allowing rapid calculation of low-point (vertex) coordinates and conductor relative levels al arbitrary points along the span. Experimental results are presented, which indicate typical accuracy of computed conductor height to within approximately a conductor diameter.