Accurate methods for estimating transmission line parameters using synchronized and unsynchronized data

There is an increasing deployment of renewable energy sources in electrical power system. Designing efficient control of power system is essential in maintaining safety and reliability of the power system. Modeling of power systems plays a key role in power system analysis and designing protection and control algorithms and diverse smart grid applications. Among various power system model parameters, line parameters are key parameters, and accurate value of line parameters will ensure the reliability and accuracy of the algorithms and applications that rely on line parameters. This paper is devoted to estimating transmission line positive-sequence parameters from unsynchronized measurements of voltage and current phasors that are obtained at both terminals of the line. The series impedance and shunt admittance line parameters can be linearly estimated using the algorithm developed in this paper. The algorithm is developed based on the distributed parameter line model, and the line is assumed to be transposed. The approach developed in this paper is considered as a linear method, and the linear least square method is used to estimate the positive-sequence line parameters. The method is also applicable to synchronized measurements obtained by Phasor Measurement Unit and is able to deal with potential synchronization errors by explicitly modeling the synchronization angle. Sample results are reported to demonstrate the effectiveness of the proposed method.