Non-intrusive monitoring

Patent metadata

Field	Value
Publication number	US-11262386-B2
Application number	US-201615767635-A
Country	US
Kind code	B2
Filing date	Oct 14, 2016
Priority date	Oct 16, 2015
Publication date	Mar 1, 2022
Grant date	Mar 1, 2022

Abstract

Methods and apparatus for non-intrusive monitoring by sensing physical parameters such as electric and/or magnetic fields. Such apparatus and techniques may find application in a variety of fields, such as monitoring consumption of electricity, for example.

First claim

What is claimed is:

1. An apparatus for non-intrusive power monitoring, the apparatus comprising:
a capacitive pickup including a plurality of stacked plates, the plurality of stacked plates including a first plate and a second plate stacked such that the second plate is between the first plate and a monitored conductor;
circuitry for sensing a signal from the capacitive pickup;
an analog to digital converter to digitize the signal; and
a digital filter configured to integrate the digitized signal into a voltage measurement while rejecting low-frequency disturbances,
wherein the digital filter is a Type 3 finite impulse response (FIR) filter.

2. The apparatus of claim 1 , wherein the digital filter is configured to reject low-frequency disturbances caused by thermal drift.

3. The apparatus of claim 1 , wherein the digital filter has a frequency response that is inversely proportional to frequency.

4. The apparatus of claim 1 , wherein the digital filter introduces a phase lag of 90° at a frequency of the voltage measurement.

5. The apparatus of claim 1 , wherein the digital filter has zero group delay, introduces 90° of phase lag, and does not pass signals at zero frequency.

6. The apparatus of claim 1 , wherein the apparatus comprises a non-intrusive load monitoring apparatus coupled to the capacitive pickup, the non-intrusive load monitoring apparatus comprising:
at least one processor; and
at least one memory configured to record measurements with data resolution of at least 1 kHz, the at least one memory storing a plurality of energy monitoring applications comprising instructions, which, when executed by the at least one processor, control one or more loads, and analyze the measurements to produce a report,
wherein the non-intrusive load monitoring apparatus is configured to transmit the report over an external network and does not transmit the measurements over an external network.

7. The apparatus of claim 1 , wherein the signal from the capacitive pickup is a current signal.

8. A method of non-intrusive power monitoring, the method comprising:
sensing a signal from a capacitive pickup, the capacitive pickup including a plurality of stacked plates, the plurality of stacked plates including a first plate and a second plate stacked such that the second plate is between the first plate and a monitored conductor;
digitizing the signal; and
digitally filtering the digitized signal using a Type 3 finite impulse response (FIR) filter to integrate the digitized signal into a voltage measurement while rejecting low-frequency disturbances.

9. The method of claim 8 , wherein the digitally filtering of the digitized signal rejects low-frequency disturbances caused by thermal drift.

10. The method of claim 8 , wherein the digitally filtering of the digitized signal is performed using a digital filter having a frequency response that is inversely proportional to frequency.

11. The method of claim 8 , wherein the digitally filtering of the digitized signal is performed using a digital filter that introduces a phase lag of 90° at a frequency of the voltage measurement.

12. The method of claim 8 , wherein the digitally filtering of the digitized signal is performed using a digital filter that has zero group delay, introduces 90° of phase lag, and does not pass signals at zero frequency.

13. The method of claim 8 , wherein the signal from the capacitive pickup is a current signal.

Assignees

• Massachusetts Inst Technology

Inventors

• Donnal John Sebastian
• Paris James
• Leeb Steven B
• Lawrence David

Classifications

• G01R15/165 Primary

  measuring electrostatic potential, e.g. with electrostatic voltmeters or electrometers, when the design of the sensor is essential (electrometers with passively moving electrodes G01R5/28; measuring electrostatic fields G01R29/12; measuring charge G01R29/24; measuring in circuits with high internal resistance G01R19/0023) · CPC title

• G01R21/14

  Compensating for temperature change · CPC title

• G01R21/133

  by using digital technique · CPC title

• G01R35/005

  Calibrating; Standards or reference devices, e.g. voltage or resistance standards, "golden" references (G01R33/0035, G01R35/002 take precedence) · CPC title

• G01R29/085

  for detecting presence or location of electric lines or cables (fault detection G01R31/50; fault location G01R31/08) · CPC title