Disturbance rejection for current-measurement systems
First Claim
1. An in-hole sampled current-measurement system with uninterrupted short-circuit/overcurrent detection, system comprising:
- three or more magnetic-field sensors configured to be inserted into a hole in an electrical conductor, each sensor operative to generate a signal at an output in response to a magnetic-field strength at the sensor'"'"'s location;
a selection module coupled to each of the sensors'"'"' outputs to receive each of the sensors'"'"' respective signals representative of the magnetic-field strength at each of the sensors'"'"' respective locations;
a control module operative to control the selection module to select a subset of the magnetic-field sensors at a scheduled time of a predetermined disturbance event, and to cause a set of the non-selected magnetic-field sensors, which are scheduled to receive a disturbance associated with the predetermined disturbance event, to be deselected at the scheduled time of the predetermined disturbance event;
a continuous-measurement module coupled to the selection module to process the signals associated with the selected subset of the magnetic-field sensors to generate a continuous output signal representative of an electrical current in the electrical conductor; and
a periodic-measurement module coupled to each of the three or more magnetic-field sensors'"'"' outputs to receive each of the three or more sensors'"'"' respective signals representative of the magnetic-field strength at each of the three or more sensors'"'"' respective locations, and operative to process the received three or more magnetic-field sensors'"'"' outputs to generate a periodic output signal representative of the electrical current in the electrical conductor.
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Accused Products
Abstract
Apparatus and associated methods relate to an in-hole current-measurement system having three or more magnetic-field sensors and a transient-disturbance selection module configured to form an output signal from a selected subset of sensor signals while decoupling the output signals from a non-selected subset of sensor signals during a predetermined time window when a disturbance signal is expected at the non-selected set of sensor signals. In an illustrative example, a disturbance producing operation may be performed on alternating subsets of sensors while the undisturbed subset of sensors measures an electrical current in the electrical conductor. For example, each selected subset of sensors may be aligned on an axis configured to be mounted perpendicular to current flow within a hole in the electrical conductor. Some embodiments may advantageously provide continuous electrical current measurement while being uninterrupted by the predetermined transient disturbances.
40 Citations
17 Claims
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1. An in-hole sampled current-measurement system with uninterrupted short-circuit/overcurrent detection, system comprising:
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three or more magnetic-field sensors configured to be inserted into a hole in an electrical conductor, each sensor operative to generate a signal at an output in response to a magnetic-field strength at the sensor'"'"'s location; a selection module coupled to each of the sensors'"'"' outputs to receive each of the sensors'"'"' respective signals representative of the magnetic-field strength at each of the sensors'"'"' respective locations; a control module operative to control the selection module to select a subset of the magnetic-field sensors at a scheduled time of a predetermined disturbance event, and to cause a set of the non-selected magnetic-field sensors, which are scheduled to receive a disturbance associated with the predetermined disturbance event, to be deselected at the scheduled time of the predetermined disturbance event; a continuous-measurement module coupled to the selection module to process the signals associated with the selected subset of the magnetic-field sensors to generate a continuous output signal representative of an electrical current in the electrical conductor; and a periodic-measurement module coupled to each of the three or more magnetic-field sensors'"'"' outputs to receive each of the three or more sensors'"'"' respective signals representative of the magnetic-field strength at each of the three or more sensors'"'"' respective locations, and operative to process the received three or more magnetic-field sensors'"'"' outputs to generate a periodic output signal representative of the electrical current in the electrical conductor. - View Dependent Claims (2, 3, 4, 5)
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6. An in-hole current-measurement system with uninterrupted short-circuit/overcurrent detection, system comprising:
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three or more magnetic-field sensors configured to be inserted into a hole in an electrical conductor, each sensor operative to generate a signal at an output in response to a magnetic-field strength at the sensor'"'"'s location; a selection module coupled to each of the sensors'"'"' outputs to receive each of the sensors'"'"' respective signals representative of the magnetic-field strength at the sensor'"'"'s location; a control module operative to control the selection module to select a subset of the magnetic-field sensors at a scheduled time of a predetermined disturbance event, and to cause a set of the non-selected magnetic-field sensors, which are scheduled to receive a disturbance associated with the predetermined disturbance event, to be deselected at the scheduled time of the predetermined disturbance event; a continuous-measurement module coupled to the selection module to process the signals associated with the selected subset of the magnetic-field sensors to generate a continuous output signal representative of an electrical current in the electrical conductor; and a periodic-measurement module coupled to each of the three or more magnetic-field sensors'"'"' outputs to receive each of the three or more sensors'"'"' respective signals representative of the magnetic-field strength at each of the three or more sensors'"'"' respective locations, and operative to process the received three or more magnetic-field sensors'"'"' outputs to generate a periodic output signal representative of the electrical current in the electrical conductor; wherein outputs of a first and second magnetic-field sensor are connected to a first amplifier; wherein outputs of the second and a third magnetic-field sensor are connected to a second amplifier; wherein outputs of the third and a fourth magnetic-field sensor are connected to a third amplifier; wherein the first and third amplifier are connected to mutually exclusive pairs of magnetic-field sensors. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13)
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14. A method of measuring current in a conductor, the method comprising:
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receiving signals from outputs of N magnetic-field sensors; retrieving coefficients corresponding to the N magnetic-field sensors; summing products of the coefficients and the sensors output values to calculate a raw current measurement; retrieving a calibration coefficient from a memory; multiplying the retrieved calibration coefficient by the calculated raw current measurement to calculate a measured electrical current; initializing both a time stamp and a first pair of AMR sensors of the N magnetic-field sensors; retrieving a delta time window length during which the first pair of AMR sensors will be disabled during a set/reset operation; sending a first signal to a fast analog multiplexor to select a second pair of AMR sensors of the N magnetic-field sensors that will not be disturbed by the set/reset operation; disabling outputs of the first pair of AMR sensors; sending a command for a set/reset module to perform a set operation or a rest operation on the first pair of AMR sensors; determining the time window for disturbance has passed; enabling the outputs of the first pair of AMR sensors when the time window for the disturbance has passed; and performing the method of measuring the current in the conductor using all sensors of the first pair of AMR sensors and the second pair of AMR sensors. - View Dependent Claims (15, 16, 17)
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Specification