Background. High voltage overhead transmission line parameters can significantly change depending on weather conditions and line loading. Installation of phasor measurement units potentially allows keeping track of true line parameters. However, a few algorithms proposed earlier for this purpose are quite complex and require optimization, which makes it reasonable to obtain a rigorous analytical solution that can be applied at certain electric power facilities such as a three-phase single circuit transposed line.
Materials and methods. The analytical expressions have been derived using well-known relations from electrical engineering as well as the theory of functions. The developed algorithm has been realized in the MATLAB language and tested out on a power network model built into the ATP/ATPDraw software. The Monte Carlo method has been used to assess the effect of measurement errors: for each instrument transformer accuracy class, we conducted a series of 10,000 experiments in MATLAB and then calculated the necessary statistics.
Results. A rigorous algorithm has been derived allowing the estimation of three-phase single circuit transposed line parameters by using one set of synchronized phasor measurements on both line ends. The algorithm has been successfully verified with MATLAB and ATP/ATPDraw software. In addition, the effect of measurement errors when exploiting instrument transformers of different accuracy classes has been analyzed.
Conclusions. The proposed algorithm potentially allows us to implement a simpler (and less computationally-intensive) approach to solving the transposed overhead line parameter estimation problem based on synchrophasor measurements. Under steady-state conditions with a slight unbalance, the algorithm allows obtaining good quality results of calculating specific positive sequence line parameters for 0.5 accuracy class instrument transformers. Under highly unbalanced conditions, the algorithm can also be exploited to compute the zero sequence series resistance and reactance, even if 1.0 accuracy class transformers are used.