# US 11,079,424 B2 · Combined low frequency and high frequency current sensor

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 11,079,424 B2
- Document ID: US11079424B2
- Status: Granted
- Kind: B2
- Application number: 16/213,472
- Filed: 2018-12-07
- Published: 2020-06-11
- Granted: 2021-08-03
- Earliest claimed: 2018-12-07
- Assignees: Schneider Electric USA, Inc.
- Applicants: Schneider Electric USA, Inc.
- Inventors: Andi Jakupi; Robert Isaacson; Carlton R. Rodrigues
- Web page: https://patentgrep.com/patent/US11079424B2

## CPC

- G01R 19/0007: {Frequency selective voltage or current level measuring (measuring frequency G01R23/00; testing attenuation in line transmission systems H04B3/48; monitoring testing in transmission systems H04B17/00)}
- G01R 31/1272: {of cable, line or wire insulation, e.g. using partial discharge measurements (locating faults in cables G01R31/083)}
- G01R 15/202: {using Hall-effect devices (Hall elements in arrangements for measuring electrical power G01R21/08)}
- G01R 19/16571: {comparing AC or DC current with one threshold, e.g. load current, over-current, surge current or fault current (G01R19/16514, G01R19/16519, G01R19/16528, G01R19/16533, G01R19/1659 take precedence; measuring currents by using elements sensitive to the magnetic field generated G01R15/14; measuring earth resistance G01R27/18; testing for leakage or short circuits in electrical apparatus G01R31/52)}
- H01F 27/255: made from particles (H01F27/26 takes precedence)
- H02H 1/0007: {concerning the detecting means (in general G01R or other subclasses of G01; reed switches H01H71/2445)}
- H02H 3/10: additionally responsive to some other abnormal electrical conditions
- G01R 15/183: {using transformers with a magnetic core}
- G01R 15/207: {Constructional details independent of the type of device used}
- G01R 19/0092: {Measuring current only}
- G01R 19/165: Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
- G01R 31/1227: {of components, parts or materials (G01R31/1209, G01R31/1218, G01R31/18 take precedence; circuits therefor G01R31/14; testing vessels of electrodes G01R31/16)}
- G01R 31/52: Testing for short-circuits, leakage current or ground faults
- H02H 1/0015: {Using arc detectors}
- H02H 3/08: responsive to excess current (responsive to abnormal temperature caused by excess current H02H5/04)
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H02H: EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS (indicating or signalling undesired working conditions G01R, e.g. G01R31/00, G08B; locating faults along lines G01R31/08; emergency protective devices H01H)

## Abstract

Example embodiments of the invention include a powdered core bead body configured to become an inductive impedance to current signals in a power wire with high frequencies. The signals are detectable by a high frequency voltage sensor, which is configured to output an arc fault tripping indication to an arc fault tripping circuit. The bead body includes a magnetic flux-density sensing device embedded in an air cavity of the bead body, having a magnetic field sensing surface oriented substantially perpendicular to the circumferential periphery of the bead body. The bead body is configured to provide measurable magnetic flux through the magnetic flux-density sensing device, for currents in the power wire having low frequencies. The measurable magnetic flux is detectable by a low frequency magnetic flux-density sensing device, to output a low frequency current measurement for power metering devices or to determine power consumption within a protected branch.

## Claims

### Claim 1

A combined low frequency and high frequency current sensor, comprising:
a core bead body composed of a ferromagnetic, ferrite, or magnetic oxide material having a generally toroidal shape with a radial thickness extending between a circumferential periphery and an inner periphery surrounding a centralized circular aperture through which passes a current carrying power wire, and an air cavity formed in the core bead body with sidewalls substantially perpendicular to the circumferential periphery and extending radially inwardly for a distance less than the radial thickness forming a bottom of the cavity separated from the inner periphery of the core bead body surrounding the centralized circular aperture by a remaining thickness of the core bead body forming a shielding bridge portion, configured to provide a magnetic shield for the air cavity from variations in magnetic flux due to variations in distance of the power wire from the inner periphery of the core bead body to enable measurement of magnetic flux in the air cavity; and
a magnetic flux-density sensing device embedded in the air cavity in the core bead body, having a magnetic field sensing surface oriented substantially perpendicular to the circumferential periphery of the core bead body, configured to measure magnetic flux through the magnetic flux-density sensing device in response to current signals in the power wire.

### Claim 2 (depends on 1)

The combined low frequency and high frequency current sensor of claim 1, further comprising:
a sensing wire positioned to pass once through the aperture of the bead body, the sensing wire configured sense an occurrence of high frequency current signals in the power wire and to provide an arc fault tripping indication in response to an occurrence of high frequency current signals in the power wire.

### Claim 3 (depends on 1)

The combined low frequency and high frequency current sensor of claim 1, wherein the magnetic flux-density sensing device is a Hall-effect device.

### Claim 4 (depends on 1)

The combined low frequency and high frequency current sensor of claim 1, further comprising:
a high frequency voltage sensor having a first input terminal coupled to a first portion of the power wire and a second input terminal coupled to a second portion of the power wire, configured to provide an arc fault tripping indication in response to an occurrence of high frequency current signals in the power wire.

### Claim 5 (depends on 4)

The combined low frequency and high frequency current sensor of claim 4, further comprising:
an arc fault tripping circuit configured to interrupt or trip electrical current in the power wire, if an output from the high frequency voltage sensor indicates that an arc-fault is detected, the arc fault tripping circuit having an input coupled to the high frequency voltage sensor.

### Claim 6 (depends on 1)

The combined low frequency and high frequency current sensor of claim 1, further comprising:
a low frequency voltage sensor having an input terminal coupled to an output connection of the magnetic flux-density sensing device, configured to sense a low frequency variation of the magnetic flux in the bead body, sensed by the magnetic flux-density sensing device and to output an indication of an over-current fault in the power wire.

### Claim 7 (depends on 6)

The combined low frequency and high frequency current sensor of claim 6, further comprising:
an over-current fault tripping circuit configured to interrupt or trip electrical current in the power wire, if an output from the low frequency voltage sensor indicates that an over-current fault or a ground-fault is detected, the over-current fault tripping circuit having an input coupled to the low frequency voltage sensor.

### Claim 8 (depends on 1)

The combined low frequency and high frequency current sensor of claim 1, wherein the core bead body is configured to become an inductive impedance to current signals in the power wire with frequencies in the 1 MHz to 40 MHz range.

### Claim 9 (depends on 1)

The combined low frequency and high frequency current sensor of claim 1, wherein the core bead body is configured to provide measurable magnetic flux through the magnetic flux-density sensing device, for currents in the power wire having frequencies from DC up to 20 kHz, the measurable magnetic flux being detectable by the low frequency magnetic flux-density sensing device, which is configured to provide a fault tripping indication.

### Claim 10 (depends on 2)

The combined low frequency and high frequency current sensor of claim 2, further comprising:
a high frequency voltage sensor having a first input terminal coupled to a first portion of the sensor wire and a second input terminal coupled to a second portion of the sensor wire, configured to sense an occurrence of high frequency current signals in the power wire and to provide an arc fault tripping indication in response to an occurrence of high frequency current signals in the power wire.

### Claim 11

A low frequency current measurement power metering device, comprising:
a core bead body composed of a ferromagnetic, ferrite, or magnetic oxide material having a generally toroidal shape with a radial thickness extending between a circumferential periphery and an inner periphery surrounding a centralized circular aperture through which passes a current carrying power wire, and an air cavity formed in the core bead body with sidewalls substantially perpendicular to the circumferential periphery and extending radially inwardly for a distance less than the radial thickness forming a bottom of the cavity separated from the inner periphery of the core bead body surrounding the centralized circular aperture by a remaining thickness of the core bead body forming a shielding bridge portion, configured to provide a magnetic shield for the air cavity from variations in magnetic flux due to variations in distance of the power wire from the inner periphery of the core bead body to enable measurement of magnetic flux in the air cavity, having a power wire passing through the bead; and
a magnetic flux-density sensing device embedded in the air cavity in the core bead body, having a magnetic field sensing surface oriented substantially perpendicular to the circumferential periphery of the core bead body, configured to provide measurable low frequency magnetic flux through the magnetic flux-density sensing device in response to current signals with low frequencies in the power wire, the magnetic flux-density sensing device configured to provide low frequency current measurement in response to an occurrence of the low frequency measurable magnetic flux.

### Claim 12 (depends on 11)

The low frequency current measurement power metering device of claim 11, wherein the magnetic flux-density sensing device is a Hall-effect device.

### Claim 13 (depends on 11)

The low frequency current measurement power metering device of claim 11, further comprising:
a low frequency voltage sensor having an input terminal coupled to an output connection of the magnetic flux-density sensing device, configured to sense a low frequency variation of the magnetic flux in the bead body, sensed by the magnetic flux-density sensing device and to output a low frequency current measurement in response to an occurrence of the low frequency measurable magnetic flux.

### Claim 14 (depends on 11)

The low frequency current measurement power metering device of claim 11, wherein the core bead body is configured to provide measurable magnetic flux through the magnetic flux-density sensing device, for currents in the power wire having frequencies between DC and up to 20 kHz, the measurable magnetic flux being detectable by the low frequency magnetic flux-density sensing device, which is configured to provide a low frequency current measurement in response to an occurrence of the low frequency measurable magnetic flux.