Method and apparatus for transmission line phase angle comparisons

摘要

A method for internal fault detection comprises determining whether a local current on a local transmission line terminal exceeds a variable first fault level threshold; if so, determining whether a remote current on a remote transmission line terminal exceeds a variable second fault level threshold; and if so, comparing phases of the local and remote currents. The method can include determining local and remote uncertainty factors for the local and remote currents and using the uncertainty factors to adjust the variable thresholds. The method can further include measuring a current on a local transmission line terminal and bandpass filtering the measured current to obtain the local current.