Method and apparatus for detecting and locating faults in an AC transmission line using two indicators
First Claim
1. Apparatus for providing a visual indication of whether a transmission line connecting an AC source to a load is open-circuited and/or short-circuited comprising:
- means disposed along said transmission line for sensing the current and voltage carried by said line;
first and second discrete visual indicators; and
control means, operatively coupled to said sensing means and said first and second visual indicators, for selectively illuminating said first and second visual indicators in response to said sensed current and voltage as follows;
(a) illuminating both said first and second indicators when the source is delivering an AC signal to the line and the line is not open or shorted(b) illuminating said first indicator and darkening said second indicator when said line is discontinuous somewhere between the point along said line at which said sensing means is disposed and said load,(c) darkening said first indicator and illuminating said second indicator when said line is shorted somewhere between the point along said line at which said sensing means is disposed and said load, and(d) darkening both said first and second indicators whenever any one of the following conditions exist;
(1) said source is not delivering a signal to said line(2) said line is shorted somewhere between said source and the point along said line line at which said sensing means is disposed, and(3) said line is discontinuous somewhere between the source and the point along said line at which said sensing means is disposed.
1 Assignment
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Accused Products
Abstract
A low-cost transmission line fault detector visually indicates the nature and location of transmission line failures. A current detection circuit inductively coupled to the transmission line produces an output signal when current is flowing through the line. A voltage detection circuit directly coupled across the transmission line monitors the relative potential across the line and produces an output signal when the relative potential is within predefined limits. By observing the states of the outputs of the current and voltage detection circuits (e.g., through visual indications provided by light emitting diodes), one can tell if the transmission line has shorted or open-circuited, and if it has, the location of the failure (e.g., between the source and the detector coupling point or between the detector coupling point and the load).
37 Citations
10 Claims
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1. Apparatus for providing a visual indication of whether a transmission line connecting an AC source to a load is open-circuited and/or short-circuited comprising:
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means disposed along said transmission line for sensing the current and voltage carried by said line; first and second discrete visual indicators; and control means, operatively coupled to said sensing means and said first and second visual indicators, for selectively illuminating said first and second visual indicators in response to said sensed current and voltage as follows; (a) illuminating both said first and second indicators when the source is delivering an AC signal to the line and the line is not open or shorted (b) illuminating said first indicator and darkening said second indicator when said line is discontinuous somewhere between the point along said line at which said sensing means is disposed and said load, (c) darkening said first indicator and illuminating said second indicator when said line is shorted somewhere between the point along said line at which said sensing means is disposed and said load, and (d) darkening both said first and second indicators whenever any one of the following conditions exist; (1) said source is not delivering a signal to said line (2) said line is shorted somewhere between said source and the point along said line line at which said sensing means is disposed, and (3) said line is discontinuous somewhere between the source and the point along said line at which said sensing means is disposed. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. Method of indicating whether a transmission line connecting a source to a load is open-circuited and/or short-circuited, comprising the steps of:
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illuminating both a first and a second discrete visual indicator when the source is delivering a signal to said transmission line and said line is not open or shorted; illuminating said first indicator and darkening said second indicator when said line is open somewhere between a preset point along said transmission line and said load; darkening said first indicator and illuminating said second indicator when said transmission line is shorted somewhere between said preset point and said load; darkening both said first and second indicators when said line is shorted somewhere between said source and said preset point; and darkening both said first and second indicators when said line is open somewhere between said source and said preset point.
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10. In a transmission system of the type including an AC signal source, a load, and a transmission line connecting the load to the source, a fault detector comprising:
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detecting/indicating means for detecting open circuits and short-circuited in said transmission line; and coupling means for coupling said detecting/indicating means to said transmission line at a preset point along said line. said detecting/indicating means programmed to perform the following functions in response to the voltage and current carried by said transmission line; producing first and second output signals when the source is delivering a signal to said transmission line and said line is not open or shorted; producing said first signal but not said second signal when said line is open somewhere between said preset point and said load; producing said second signal but not said first signal when said line is shorted somewhere between said preset point and said load; producing neither said first nor said second signals when said line is shorted somewhere between said source and said preset point; and producing neither said first nor said second signals when said line is open somewhere between said source and said preset point.
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Specification