Method and apparatus for transmission line phase angle comparisons
AssigneeGeneral Electric Company
InventorWilliam James Premerlani
Life of this patent
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Abstract
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.
Claims11
A method for transmission line phase angle comparisons for internal fault detection comprising:
- determining whether a local current on a local transmission line terminal exceeds a variable first fault level threshold by computing a local uncertainty factor for the local current and using the local uncertainty factor to adjust the variable first fault level threshold;
- determining whether a remote current on a remote transmission line terminal exceeds a variable second fault level threshold by computing a remote uncertainty factor for the remote current and using the remote uncertainty factor to adjust the variable second fault level threshold;
- and
- if the local current on the local transmission line terminal exceeds the variable first fault level threshold and the remote current on the remote transmission line terminal exceeds the variable second fault level threshold, comparing phases of the local and remote currents.
An apparatus for transmission line phase angle comparisons for internal fault detection comprising:
- a current sensor for sensing a local current on a local transmission line terminal;
- and
- a computer for
- determining whether the local current exceeds a variable first fault level threshold by computing a local uncertainty factor for the local current and using the local uncertainty factor to adjust the variable first fault level threshold,
- determining whether a remote current on a remote transmission line terminal exceeds a variable second fault level threshold by computing a remote uncertainty factor for the remote current and using the remote uncertainty factor to adjust the variable second fault level threshold;
- and
- if the local current on the local transmission line terminal exceeds the variable first fault level threshold and the remote current on the remote transmission line terminal exceeds the variable second fault level threshold, comparing phases of the local and remote currents.
The apparatus of claim 11 further including a bandpass filter for filtering the local current and wherein the computer is adapted to use the filtered local current for determining whether the local current exceeds the variable first fault level threshold and comparing the phases of the local and remote currents.
Dependencies are inferred from the claim text.