SYSTEM FOR SELF-POWERED, WIRELESS MONITORING OF ELECTRICAL CURRENT, POWER AND ENERGY

• US 20110291488A1
• Filed: 05/28/2010
• Published: 12/01/2011
• Est. Priority Date: 05/28/2010
• Status: Active Grant

• Current Assignee: Schneider Electric IT Corporation (Schneider Electric SE)
• Original Assignee: Schneider Electric IT Corporation (Schneider Electric SE)
• Inventors: Deokar, Vishwas Mohaniraj, Donalds, James H., Paik, Namwook
• Granted Patent: US 9,267,826 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: G01D 21/00 Measuring or testing not otherwise provided for
• CPC Class Codes: G01R 15/183 using transformers with a magnetic core
• CPC Class Codes: G01R 15/26 using modulation of waves other than light, e.g. radio or acoustic waves
• CPC Class Codes: H01F 27/427 for current transformers
• CPC Class Codes: H02J 3/00 Circuit arrangements for ac mains or ac distribution networks
• CPC Class Codes: Y04S 20/00 Management or operation of end-user stationary applications or the last stages of power distribution; Controlling, monitoring or operating thereof

Abstract

According to one aspect, embodiments of the invention provide a system for monitoring at least one circuit branch coupled to a power line, the system comprising at least one first module comprising a Current Transformer (CT) configured to be coupled to the at least one circuit branch and to produce a reference signal having a level related to a current level of the at least one circuit branch, a rectifier coupled to the CT and configured to produce a rectified reference signal, a capacitor coupled to the rectifier, and a first microcontroller coupled to the capacitor and the rectifier, wherein, the capacitor is configured to store energy from the rectified reference signal, and wherein, the first microcontroller is configured to be powered by the energy stored in the capacitor and to sample the rectified reference signal to determine the current level of the at least one circuit branch.

Claims

1. A system for monitoring at least one circuit branch coupled to a power line, the system comprising:

at least one first module comprising;

a Current Transformer (CT) configured to be coupled to the at least one circuit branch and to produce a reference signal having a level related to a current level of the at least one circuit branch;

a rectifier coupled to the CT and configured to produce a rectified reference signal;

a capacitor coupled to the rectifier; and

a first microcontroller coupled to the capacitor and the rectifier,

wherein, the capacitor is configured to store energy from the rectified reference signal, and

wherein, the first microcontroller is configured to be powered by the energy stored in the capacitor and to sample the rectified reference signal to determine the current level of the at least one circuit branch.

2. The system of claim 1, further comprising:

a second module comprising;

a first input configured to be coupled to a circuit branch; and

a second microcontroller coupled to the first input and configured to measure at least one of voltage, phase and frequency of the circuit branch and transmit the at least one of the voltage, the phase and the frequency to the first microcontroller.

3. The system of claim 2, wherein the first microcontroller is configured to receive the at least one of the voltage, the phase, and the frequency, and calculate power level of the at least one circuit branch using at least one sample of the rectified reference signal and the received at least one of the voltage, the phase and the frequency.

4. The system of claim 3, wherein the second module is contained in a separate housing from the at least one first module.

5. The system of claim 4, further comprising a first antenna coupled to the first microcontroller and a second antenna coupled to the second microcontroller, and wherein the second antenna is configured to broadcast the at least one of the voltage, the phase and the frequency of the circuit branch to the first antenna.

6. The system of claim 5, wherein the first antenna is configured to broadcast the calculated power level and the current level of the at least one circuit branch to the second antenna.

7. The system of claim 1, wherein the at least one first module includes a plurality of daisy chained first modules, each having a capacitor and each configured to be coupled to a circuit branch.

8. The system of claim 7, wherein the capacitors of the plurality of first modules are coupled together.

9. A method for monitoring at least one circuit branch coupled to a power line, the method comprising:

coupling a Current Transformer (CT) to the at least one circuit branch and producing, in a first module, a reference signal having a level related to a current level of the at least one circuit branch;

storing energy from the reference signal in a capacitor;

determining if voltage across the capacitor exceeds a first threshold;

in response to a determination that the voltage across the capacitor exceeds the first threshold, powering a microcontroller using energy stored in the capacitor; and

sampling the reference signal by the microcontroller to determine the current level of the at least one circuit branch.

10. The method of claim 9, further comprising:

monitoring, by a second module coupled to the power line, at least one of voltage, phase and frequency of the power line; and

transmitting the at least one of the voltage, the phase and the frequency to the microcontroller.

11. The method of claim 10, further comprising receiving, by the first module, the at least one of the voltage, the phase, and the frequency transmitted by the second module and calculating power level of the at least one circuit branch using at least one sample of the reference signal and the received at least one of the voltage, the phase and the frequency.

12. The method of claim 10, wherein the act of transmitting includes transmitting the at least one of the voltage, the phase and the frequency through an antenna.

13. The method of claim 11, further comprising transmitting the calculated power level of the at least one circuit branch from the first module to the second module through an antenna.

14. The method of claim 10, further comprising:

determining if voltage across the capacitor is less than a second threshold; and

entering, in response to a determination that the voltage across the capacitor is less than the second threshold, a low power mode.

15. The method of claim 14, wherein entering a low power mode comprises:

periodically transmitting, from the first module to the second module, a series of pulses,

wherein an interval between pulses is based on the current level of the at least one circuit branch; and

measuring, by the second module, the interval between pulses and estimating the current of the at least one circuit branch.

16. A system for monitoring at least one circuit branch coupled to a power line, the system comprising:

at least one first module comprising;

a Current Transformer (CT) configured to be coupled to the at least one circuit branch and to produce a reference signal having a level related to a current level of the at least one circuit branch; and

means for storing energy from the reference signal and for powering a microcontroller to sample the reference signal to determine the current level of the at least one circuit branch.

17. The system of claim 16, further comprising:

a second module comprising;

means for measuring at least one of voltage, phase and frequency of the power line and for transmitting the at least one of the voltage, the phase and the frequency to the microcontroller.

18. The system of claim 17, further comprising:

means for receiving, by the first module, at least one of the voltage, the phase, and the frequency transmitted by the second module, for calculating the power level of the at least one circuit branch using at least one sample of the rectified reference signal and the received at least one of the voltage, the phase and the frequency, and for transmitting the calculated power level and the current level of the at least one circuit branch to the second module.

19. The system of claim 18, wherein the second module is contained in a separate housing from the at least one first module.

20. The system of claim 16, wherein the at least one first module includes a plurality of daisy chained first modules, each having means for storing energy and each configured to be coupled to a circuit branch.