Estimação de parâmetros elétricos de linhas de transmissão utilizando medições sincrofasoriais

Abstract

In the hereby study, it is presented the application of a method for transmission line electrical parameters estimation based on real measured values provided by Phasor Measurements Units. This exercise is carried out for the Brazilian Electrical System and aims in providing subsidies for the implementation of real-time monitoring applications of these parameters. To do so, a nonlinear optimization problem was formulated in order to simulate the system and calculate the mentioned parameters. The objective function of such a practical nonlinear optimization problem is based on the least squares method, from the nodal equations of the transmission line represented by the equivalent three-phase Π model. The constraints imposed on this nonlinear optimization problem were conditioned in relation to the parameters to be estimated. In parallel, a brief discussion is made about the factors that cause the greatest influence on the values of these parameters, in order to investigating possible discrepancies in the values of the parameters found, in comparasion with a common reference, as well as investigating a possible influence of the external enviroment on values of transmission line electrical parameters. The verified results reveals the importance of the Synchronized Phasorial Measurement Systems Instrumentation Channels, highlighting a great dependence on positive sequence parameters for measurement errors, mainly angular measurements errors. However, this work and its results show the full potential of applying this technology in Electrical Energy Systems and, consequently, in the Interconnected National System.