Novel technique for transmission line parameters estimation using synchronised sampled data

Abstract

Accurate transmission line parameters values are of high importance in setting protection relays and rigorous locating faults that may occur along the transmission network. For this purpose, the work reported in this study presents a new technique for the delicate determination of transmission lines parameters that are uniformly distributed along the line length. The developed technique is able to approximate the steady-state profiles for the transmission line voltage and current as a function of time and line length by given sets of polynomials that, in turn, are substituted in model equations. Synchronised time-domain data, recorded from both line terminals, are utilised as boundary conditions for the distributed-parameter transmission line model. The well-known Galerkin method is adopted to transform the line model into a system of non-linear algebraic equations to be solved. This system of algebraic equations is converted to residuals that are consequently regrouped in a cost function to be optimised. Thereby, the series resistance, series inductance and the shunt capacitance per line length are the parameters minimising the cost function. Both simulations and calculation are performed with MATLAB software. The obtained results show the effectiveness and accuracy of the new approach.