Innovative method to identify the impedance parameters of a three-phase electric power medium-size transmission line

This paper proposes a new method of dynamic estimation based on a linear quadratic estimation (LQE) to identify the parameters of impedance and admittance of a three-phase electric power medium-size transmission line using measurements provided by phasor units. First, a novel set of phasor equations for the steady-state operation of a medium-length transmission line are introduced. Then, the equations are transformed based on unscented transformation into a dynamic system model. The effectiveness of the new method is validated through the comparison of the results based on simulated data provided by two types of phasor unit models during step variation in line voltage and frequency. One model represents a typical phasor unit that adopts Fourier Transform-Based (FT-Based) algorithm, while the second one is adopting an unscented transform-based algorithm. Simulations have demonstrated the effectiveness of the proposed method for both models when step variation in line voltage and frequency occurs in the transmission line.