Electric meter, an electric meter system and a method of providing branch-level readings for a power distribution network

Patent metadata

Field	Value
Publication number	US-10228400-B2
Application number	US-201515307162-A
Country	US
Kind code	B2
Filing date	Apr 30, 2015
Priority date	Apr 30, 2014
Publication date	Mar 12, 2019
Grant date	Mar 12, 2019

Abstract

According to various embodiments, there is provided an electric meter including a sensor circuit configured to provide a plurality of instantaneous magnetic field measurements; a processing circuit configured to generate a time-series of magnetic field vectors, each magnetic field vector of the time-series of magnetic field vectors including the plurality of instantaneous magnetic field measurements; and a total current determination circuit configured to determine a total current, wherein the total current is a sum of currents of each branch of a plurality of branches of a power distribution network; wherein the processing circuit is further configured to compute a de-mixing matrix based on the determined total current and the time-series of magnetic field vectors, and further configured to linear transform each magnetic field vector using the de-mixing matrix to determine a current of each branch.

First claim

The invention claimed is:

1. An electric meter comprising:
a sensor circuit configured to provide a plurality of instantaneous magnetic field measurements;
a processing circuit configured to generate a time-series of magnetic field vectors, each magnetic field vector of the time-series of magnetic field vectors comprising the plurality of instantaneous magnetic field measurements;
a measurement device configured to provide a measurement of a total current of a plurality of branches of a power distribution network; and
a total current determination circuit configured to determine the total current based on the measurement from the measurement device;
wherein the processing circuit is further configured to compute a de-mixing matrix based on the determined total current and the time-series of magnetic field vectors, and further configured to linear transform each magnetic field vector using the de-mixing matrix to determine a current of each branch of the plurality of branches, and
wherein the de-mixing matrix is an inverse of a mixing matrix having full column rank, the mixing matrix defining a linear relationship between said each magnetic field vector and a corresponding current vector comprising a plurality of instantaneous currents of the plurality of branches.

2. The electric meter of claim 1 , wherein each instantaneous magnetic field measurement of the plurality of instantaneous magnetic field measurements is a measurement of a sum of magnetic fields resulting from a subset of the plurality of branches.

3. The electric meter of claim 1 , further comprising an attachment member configured to attach the sensor circuit above an electricity distribution board.

4. The electric meter of claim 1 , wherein the sensor circuit comprises a plurality of magnetic field sensors, a quantity of the plurality of magnetic field sensors being at least equal to a quantity of the plurality of branches.

5. The electric meter of claim 4 , wherein at least one magnetic field sensor of the plurality of magnetic field sensors is an anisotropic magnetoresistance sensor.

6. The electric meter of claim 4 , wherein each magnetic field sensor of the plurality of magnetic field sensors is positioned in a vicinity of a respective circuit breaker of a plurality of circuit breakers of an electricity distribution board.

7. The electric meter of claim 4 , wherein the sensor circuit further comprises a plurality of supporting circuits, each supporting circuit of the plurality of supporting circuits coupled to a respective magnetic field sensor of the plurality of magnetic field sensors.

8. The electric meter of claim 7 , wherein each supporting circuit comprises a high pass filter.

9. The electric meter of claim 7 , wherein each supporting circuit is configured to receive analog signals from the respective magnetic field sensor and further configured to at least one of amplify the analog signals or shift a direct current bias of the analog signals.

10. The electric meter of claim 1 , further comprising an installer configured to turn off all branches of the plurality of branches and then sequentially turn on each branch.

11. The electric meter of claim 1 , wherein the processing circuit is configured to identify a dominant branch, the dominant branch being one of an only branch of the plurality of branches having a non-zero current or an only branch of the plurality of branches having a non-zero change in current.

12. The electric meter of claim 11 , wherein the processing circuit is configured to compute a de-mixing matrix based on a plurality of identified dominant branches.

13. The electric meter of claim 1 , wherein the processing circuit is configured to compute a de-mixing matrix by performing an independent component analysis computation.

14. The electric meter of claim 1 , wherein the processing circuit is configured to generate a measurement dataset and further configured to estimate the current of each branch of the plurality of branches based on the measurement dataset and maximisation of a statistical independence between the current of each branch of the plurality of branches, to determine an intermediate matrix.

15. The electric meter of claim 14 , wherein the processing circuit is configured to re-order the intermediate matrix; and
further configured to scale the intermediate matrix based on the total current.

16. The electric meter of claim 14 , wherein the processing circuit is configured to generate the measurement dataset based on
determining a differential magnetic field vector, wherein the differential magnetic field vector is a difference between a magnetic field vector and a preceding magnetic field vector; and
for a plurality of time cycles, appending the differential magnetic field vector to the measurement dataset.

17. The electric meter of claim 1 , wherein the processing circuit comprises a secondary supporting circuit configured to receive analog signals from the sensor circuit.

18. The electric meter of claim 17 , wherein the secondary supporting circuit is further configured to at least one of remove external interferences from the analog signals, amplify the analog signals or shift a direct current bias of the analog signals.

19. The electric meter of claim 1 , wherein the processing circuit comprises an analog-to-digital converter.

20. The electric meter of claim 1 , wherein the processing circuit comprises a processor configured to at least one of generate the magnetic field vectors, compute the de-mixing matrix or linear transform the magnetic field vectors.

21. The electric meter of claim 1 , wherein the processing circuit comprises a transceiver configured to communicate with at least one of a user interface, a measurement device or a further processing circuit.

22. The electric meter of claim 21 , wherein the transceiver is configured to wirelessly communicate with the at least one of a user interface, a measurement device or a further processing circuit.

23. The electric meter of claim 1 , wherein the processing circuit is further configured to determine a power consumption of each branch of the plurality of branches based on the current usage of the respective branch.

24. The electric meter of claim 1 , further comprising a user interface configured to display a measurement of at least one branch of the plurality of branches.

25. An electric meter system comprising:
a plurality of electric meters;
a mother processing circuit;
a measurement device configured to provide a measurement of a total current of a plurality of branches of a power distribution network; and
a total current determination circuit configured to determine the total current based on the measurement from the measurement device;
wherein each electric meter of the plurality of electric meters comprises
a sensor circuit configured to provide a plurality of instantaneous magnetic field measurements; and
a daughter processing circuit configured to generate a time-series of magnetic field vectors, each magnetic field vector of the time-series of magnetic field vectors comprising the plurality of instantaneous magnetic field measurements;
wherein the mother processing circuit is configured to receive partially processed data from at least one electric meter of the plurality of electric meters and further configured to provide a current reading to a user interface;
wherein at least one of the mother processing circuit or the daughter pro

Assignees

• Illinois At Singapore Pte Ltd
• Agency Science Tech & Res

Inventors

• Chen Binbin
• Viswanathan Sreejaya

Classifications

• G01R22/10 Primary

  using digital techniques · CPC title

• G01R19/2513

  Arrangements for monitoring electric power systems, e.g. power lines or loads; Logging · CPC title

• G01R15/205

  using magneto-resistance devices, e.g. field plates · CPC title