A method to measure zero sequence impedances of transmission lines by using the two-terminal measured data

Based on Global Positioning System (GPS), a new method to measure the zero sqeuence impedance of transmission lines by using the two-terminal measured voltage and current data of lines is proposed. The mathematical model of the new method is explained in detail. The hardware structure of the measuring system based on GPS technology is given. Digital simulation results with different frequencies of the external source are given and comparied with the traditional method. Simulation results prove that the new method can improve the measurement accuracy of the transmission lines´ zero sqeuence impedances.