Abstract:
The non-linear high-frequency impedance measured by the ELIS of the grounding electrode lines cannot be directly used for fault location. This paper analyzes the characteristics of the amplitude and phase angles of the high-frequency measured impedance with the changes of the fault distances. Based on the amplitude and phase angle periodic characteristics of the measured impedance under the faults, the table of amplitude and phase angle values is built, realizing the determination of the fault section. On this basis, by analyzing the approximate linear monotonic characteristic of the phase angle value in a short section, a fault location expression is proposed related to the phase angle value at the boundary of the section, achieving the double-line fault location based on the amplitude-phase angle characteristics of the high-frequency measured impedance of the grounding electrode line. Simulation verifies the effectiveness and accuracy of the proposed location under various operating conditions. This method is significantly able to reduce the difficulty in the troubleshooting and facility maintenance of the grounding electrode lines in the high-voltage direct current transmission system.