WO2012007831A2

WO2012007831A2 - Circuit breaker with integral meter and wireless communications

Info

Publication number: WO2012007831A2
Application number: PCT/IB2011/001639
Authority: WO
Inventors: Kevin L. Cousineau; James B. Dehlsen
Original assignee: Levelation
Priority date: 2010-07-16
Filing date: 2011-07-14
Publication date: 2012-01-19
Also published as: WO2012007831A3

Abstract

A remote data collection for a circuit breaker panel is disclosed. Circuit panel current and/or time data is collected from one or more intelligent circuit breakers having built in data acquisition. The data are communicated to a host computer. Simultaneously the line voltage is measured and specific load power and energy usage of each breaker is calculated in real-time at the host computer. The specific load power and energy usage of each breaker is transmitted to a remote computer, which may be a homeowner's personal computer, for analysis and control.

Description

CIRCUIT BREAKER WITH INTEGRAL METER AND WIRELESS

COMMUNICATIONS BACKGROUND

Field

This application relates generally to the field of sub- metering of electrical power distribution and more particularly to individual circuit breakers incorporating integrated visual metering with wireless, radio and/or cellular communications within conventional form factor packaging.

Related Art

As energy cost increase, commercial building owners, tenants and individual homeowners seek greater visibility with respect to actual electrical energy usage by individual sub- circuits connected to the building or homes main circuit breaker panel. Creation of individual, intelligent, circuit breakers with the capability of logging power and energy use of on each of these circuits along with identification and logging of select loads on that same circuit, becomes even more important because the creation of multiple individual metered circuits using standard utility meters is both cost and space prohibitive.

Automated Meter Reading (AMR) for standard industrial and residential electrical usage meters has been developed to allow remote and/or automated reading of meters for electrical power usage. While still providing a visual meter for reference by the property owner, remote communication for meter readers and the utility supplying the power reduces the service costs for data gathering on power usage as well as reducing requirements for direct access to the meter for reading. Wireless and Radio Frequency communication has been developed for AMR capability allowing utility company employees to "read" meters from the street or other location proximate the building without having to physically read the visual meter indication with the associated required access.

Similarly, devices for monitoring individual circuits or devices within residential power systems have been developed for informing consumers about energy usage of appliances and overall control of energy consumption. Use of wireless communication from these monitoring devices allows data gathering using conventional personal computer systems or similar devices.

It is therefore desirable to provide sub-metering of

electrical power usage within the master circuit panel for commercial or private buildings (e.g. multi-unit buildings).

It is further desirable that the sub-metering capability be provided with standard form factor components within existing circuit panels.

It is also desirable that the sub-metering capability allow remote data collection as well as visual usage indicators at the panel to ascertain cost of usage per unit instead of the current standard practice of building total power cost/ total sq ft of the tenant's unit or industrial subsection or department

building.

SUMMARY

Exemplary embodiments provide a circuit breaker having a case with a form-factor interchangeable with conventional circuit breakers. Conventional, home style, single phase, circuit breakers have only two terminals because they are connected only between a utility current-source and a load.

Since they are in series with the load, they do not have a neutral connection. Without a neutral connection, these devices do not have the capability to measure the line voltage and without a line voltage measurement, there is no method of determining individual circuit power draw or energy usage either. However, using current transformers, it is possible to provide not only a measure the circuit current in series with the load but provide a small amount of power for operating low and micro-power electronic components, such as microprocessors. Such a system allows the circuit breaker to transmit its current flow measurements to a host computer that simultaneously measure the line voltage and calculates the specific load power and energy usage in real time. Now the commercial tenant or

homeowner has the ability to view these computed values for each load once communication is established between this host

computer and the homeowners or commercial tenants Personal computer (PC) .

In addition to individual circuit data acquisition the intelligent circuit breaker can also provide the basic

protection functions found in conventional circuit breakers including overload, and short circuit protection. In fact this should be the primary function of the breaker with the data acquisition function as a side benefit of its operation as an intelligent breaker system.

The features, functions, and advantages that have been discussed can be achieved independently in various embodiments of the present invention or may be combined in yet other

embodiments further details of which can be seen with reference to the following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of an exemplary standard form factor circuit breaker employing the present embodiments;

FIG. 2 is a block diagram of the operational elements of the intelligent circuit breaker of the present embodiments;

FIG. 3 is a block diagram of a host computer used to measure line voltage and determine overall power and energy usage by the intelligent circuit breaker of the present embodiments; and

FIG. 4 is a block diagram of the overall system in which the present invention is embodied.

DETAILED DESCRIPTION

Referring to FIG. 1 of the drawings, embodiments of the

"intelligent" breaker are incorporated within the form factor of a conventional breaker case 10. Initial embodiments are

anticipated in single to three pole breakers with current ratings of 10 to 200 amperes. Alternative embodiments may employ breakers with higher current capability as well. A conventional circuit breaker switch 12 is employed for manual

connection/disconnection of the circuit. A display 14 may be a liquid crystal display (LCD) or a multi-digit rotary solenoid type integrated into the case for visual verification of the actual current usage by the circuit on which the breaker is connected. These applications are for single phase metering. Another alternative embodiments may include multi-phase metering and there the circuit breaker has the capability of measuring voltage directly. This would imply that the host computer system would have less duties but the overall performs is quite similar and the operational requirements remain the same.

As shown in FIG. 2, the intelligent breaker employs a standard circuit breaker mechanism 16 (Kl a mechanical relay) with a manual switch 12. In an exemplary embodiment a small current transformer 28 is used to measure the actual current in the circuit and simultaneously provide power 24 for the

remaining electronics within the breaker including the breaker microcontroller 38. This breaker microcontroller 38 receives the actual current, converted to digital format by its internal

Analog to Digital converter, rectified and filtered by the True RMS converter block 36. An energy harvester 24 is used in conjunction with a small amount of bulk energy storage to supply continuous current to the internal circuit breaker electronics during period of low current flow through the current

transformer (CT) 26. The microcontroller, through its program, determines the correct levels required to activate the relay driver 39 to open the circuit breaker in order to protect the circuit operating through this breaker. Since the

microcontroller 38 keeps track of time from its built in

oscillator, it can also keep track of current versus time and therefore make the correct intelligent decision concerning over- current protection. Short circuit protection is provided by the microcontroller to open the breaker once the current exceeds a specific level for only a short period of time. Overall

protection, as with all breakers, is on an overload current versus time equation. These are standard calculations within the over current protection area.

Besides the basic circuit breaker functions described above, the intelligent breaker also functions as a data acquisition system with real time data transmission of circuit current flow (amperage) recording and transmission to a host computer shown in FIG. 3. These data functions are essentially parallel to the circuit breaker function in that the microcontroller must record current and time, store these values and simultaneously transmit them over a wireless transceiver 40 or a serial communication 42. The wireless connection is shown here as a Bluetooth™ wireless device 40. The serial communication 42 can be a hard wire CAN BUS or other serial connection to 443 to the host computer shown in FIG. 3. Bluetooth™ is a proprietary open wireless technology standard for exchanging data over short distances using short wavelength radio transmissions. It was originally conceived as a wireless alternative to RS-232 data cables. The CAN BUS or other standard communication technology such as RS-232, 585 or 422 serial can be used in a unique fashion by attachment of a pre-fabricated bus bar connection that will "snap-on" or be built into a standard DIN Rail Mount used for industrial equipment.

Besides this communication, the microcontroller 38 may write some of the data acquisition values to the LCD display 44 for an immediate feedback to anyone who opens the breaker panel and examines the operation of the internal breakers. Using proper protocol between the Intelligent Circuit Breaker (ICB) and the host computer, this display may be set to show an average, peak or other data as the program may require or feature. Although a Bluetooth™ type of radio wireless transceiver 40 is shown herein, there are other types of radio systems that may be suitable. Each requires operation at low power however, as the CT is not capable of providing large amount of power for this operation.

Refer to FIG. 3, which is a block diagram of the host computer used to measure line voltage and determine overall power and energy usage by the intelligent circuit breaker of the present embodiments. The host computer is preferably located within the same circuit breaker panel 50 as the ICB modules. Because of the proximity to the other ICB modules, the power level requirements for this local wireless network are quite small, in keeping with the power needs of the ICB modules. As shown in FIG. 3 this host computer module, unlike the ICB shown in FIG.2, receives its power directly from the power line 30 by means of rectifier and DC supply 51. Because the host computer is connected to line voltage 30, it has the capability to measure the line voltage 30. The power line communications transceiver 49 is also connected to the line voltage 30 and neutral 31 and to the Internet gateway 66. The transceiver 49 is a transmitter/receiver that in conjunction with the Internet gateway 66 allows Internet access over the power lines and/or to establish a wired connection using the existing electrical wiring in a home .

Two options are shown for communication from the host computer to and from the ICB modules themselves. As discussed above these are wireless technologies such as Bluetooth™ or a dedicated hard-wired serial connection such as CAN BUS or RS-

232, 485 or 422 protocols. Connection to each of the ICB modules can be accomplish through a easy to install, "snap on" type bus bar arrangement, a communication rail located on a standard DIN type mounting rail, or some form of copper module-to-module wiring with connectors. In either case, communication from the ICB modules to the host computer enables the host computer to gather all data required calculate the actual power usage on those circuit breakers by combining their current measurement with its own voltage measurement. If these measurements are calculated based on a sample rate that is at least 5 to 20 times faster than the line frequency, (300 to 1200 samples per

second) , a fairly accurate picture can be made of the power and energy usage of these ICB's. With higher speed sampling the host computer can also determine the phase difference between the current and the voltage and thereby determine the reactive nature of the current draw as well. Since both the host computer and the ICB both measure the RMS value of voltage and current the overall output will be true watts and with the combination of phase shift, the reactive component of this measurement as well .

The host computer is also designed to have a higher speed communication gateway 66 to allow it to be connected either directly to the Internet or through a nearby server to a local area network. This communication gateway can consist of an

Ethernet cable, a high power wireless network connection, a remote AC line communication modem or a direct serial connection such as USB or RS-232 or even a fiber optic serial or Ethernet connection as well. There are multiple ways to establish this connection and the best one will be determined by a user's need. For most applications a wireless connection to a local area network will suffice. Direct serial connections for set up and programming are also available and standard applications for this type of control system exist.

The host microprocessor 61 measures the line voltage through a simple line voltage divider 48 usually consisting of a pair of resistors. However this may also be a "potential transformer" for more critical applications where isolation and accuracy are more important. In any event a lower voltage that is

proportional to the actual line voltage is then converted to a digital format by a combination of a rectifier, filter and True RMS converter 55, and the microcontrollers own analog- to-digital (A/D) converter 59. The alternating current signal out of the voltage divider 48 is converted into a direct current signal of equivalent value (known as the root mean square, RMS value) for input to the host microcontroller 61.

The functions of the host microcontroller 61 are described above, but the programming thereof can be upgraded, as new functions are needed. One function that is important to

utilities and homeowners alike is the capability of remotely disconnecting loads. Using commands to the host computer it can in turn command any single ICB to "shunt trip", which result in an open circuit breaker on that particular load. This is

accomplished by the host microcontroller 61 communicating with a particular breaker microcontroller 38 (FIG. 2) , through its programming, to activate the relay driver 39 to open the circuit breaker in order to disconnect the circuit operating through this breaker. It will be understood by those skilled in the art that the relay driver 39 may include circuitry to reset the circuit breaker and restore the associated load. One or more monitoring and control systems may be remotely used to command the host computer to vary the overall load based on its own internal programming. This control capability allows a master monitoring and control system to actively address the power line controlled by the intelligent breaker system to disconnect during high power periods, to disconnect when a particular unit or tenancy is vacated. Of course remote monitoring by an owner of any tenant employing this system is also a built in feature.

Individual circuit power and energy usage along with overall circuit usage will be a helpful function of data collection by the host computer itself . Typical usage can be compared over time to determine when that load was running and at how much power. All of these data are very useful for long-term active energy management of a building or tenant.

Because the host computer is able to determine both the voltage and current characteristics of each individual ICB over time, this same computer system, or another remote computer such as a desk top, lap top, palm top, note book, or notepad computer may be able to review this data to discriminate loads on a single individual breaker. Load discrimination and detection can be determined by noting the differences in the turn on/turn off current versus time curves. Each load has an individual curve. For instance the load for a motor will be quite different than a resistive load such as a toaster. The tenant or homeowner can work with the software to help identify each load by operating them independently for identification purposes. Once identified, the host computer or other remote computer as described above can take advantage of this data to determine what object is being operated at what time and time interval.

Refer to FIG. 4, which is a block diagram of the overall system in which the present invention is embodied. The solid lines illustrate the confines of a breaker panel 50. Each breaker 52, 53, 54, (ICB # 1, ICB # 2 .... ICB # n) is connected to the line 30. Each ICB services a load circuit load # 1, load # 2 .... load # n, to which one or more appliances (loads) are connected. Each ICB has its own antenna 56, 57, 58, (ICB antenna # 1, ICB antenna # 2, .... ICB antenna # n) , for wireless

communication with a common host computer 60, shown in FIG. 3. The host computer 60 is connected to the power line 30 and neutral 31 entering the breaker panel from an external power grid.

The host computer 60 has a host antenna 62, which receives and transmits signals from the ICB antennas 56, 57, 58. External communication with remote devices not located at the breaker panel is provided, such remote computer 70. Remote computer 70 may have wireless capability via remote antenna 72, which can communicate with the host computer. In addition to the host antenna 62 there is provided a serial communication port 64 and an Internet connection 66 for alternate ways of communicating with the remote computer 70 as described in FIG.3. Method of Remote Data Collection

The method of remote data collection is as follows. Circuit panel 50 current and/or time data is collected from the

intelligent circuit breakers 52, 53, 54, which have built in data acquisition as shown in FIG. 2. The collected data is communicated by wireless to a common host computer 60, which is preferably located in the breaker panel 50 but may be external thereto. Simultaneously the line voltage 30 is measured (blocks 48, 55, 59 of FIG. 3) at the host computer 60. The host computer (FIG. 3) calculates specific load power and energy usage of each breaker 52, 53, 54 in real-time. Finally, the specific load power and energy usage of each breaker 52, 53, 54 is

communicated to a remote computer 70 via serial communication 64 or Internet gateway 66. At the remote computer 70 a commercial tenant or homeowner has the ability to view these computed values for each load once communication is established between this host computer and the homeowners or commercial tenants Personal computer (PC) .

Claims

1. An intelligent circuit breaker characterized by;

a built in data acquisition 26, 36, 37 to collect circuit panel current and/or time data; and

a microcontroller 38 for transmitting said data over either a wireless connection 40 or a hardwired connection 42 to a host computer 60.

2. The intelligent circuit breaker of claim 1 wherein the circuit breaker incorporates a multi-digit display 44

integrated on the case 10 for display of any number of its internal data acquisition features including current.

3. The apparatus of claim 1 wherein each intelligent circuit breaker is housed in a standard enclosure case 10 with a form-factor interchangeable with conventional circuit breakers .

4. An intelligent circuit breaker system employing one or multiple circuit breakers with built in data acquisition and control to allow for the collection of circuit panel current and/or time data;

each circuit breaker being housed in a standard enclosure case 10 with a form- factor interchangeable with conventional circuit breakers;

a host computer 60; and

a breaker microprocessor 38 based data acquisition and control system in communication with said host computer 60; said breaker microprocessor 38 used to drive 39 a relay for over-current and short-circuit protection as required for any circuit breaker, along with multiple communications media 40, 42 for connection to said host computer 60.

5. The system of claim 4 wherein said host computer 60 includes means 48, 55, 59 for gathering line voltage and/or time and for calculating 61 wattage, watt-hour and VAR data from each of said intelligent circuit breakers.

6. The system of claims 4 or 5 wherein the intelligent circuit breakers incorporate a multi-digit display 44

integrated on the breaker case 10 for display of any number of its internal data acquisition features including current.

7. The system of claim 4 or 5 or 6 wherein said host computer 60 contains Internet gateway communication media 66 for direct connection to any Internet connected device for remote monitoring and control.

8. A host computer 60 for use with one or more intelligent circuit breakers characterized by:

a host microcontroller 61 for receiving circuit panel current and/or time data from said one or more intelligent circuit breakers over either a wireless connection 74 or a hardwired connection 64, 66 to said a host computer 60.

9. The host computer of claim 8 wherein said host computer 60 contains Internet gateway communication media 66 for direct connection to any Internet connected device for remote

monitoring and control.

10. The host computer of claim 8 or 9 wherein said host computer 60 includes means 48, 55, 59 for gathering line voltage and/or time and for calculating 61 wattage, watt-hour and VAR data from each of said intelligent circuit breakers.

11. A method of remote data collection comprising steps of:

A. Collecting circuit panel 50 current and/or time data from one or more intelligent circuit breakers 52, 53, 54 with built in data acquisition;

B. Communicating said data to a host computer 60; C. Simultaneously measuring the line voltage at said host computer; and

D. Calculating specific load power and energy usage of each breaker 52, 53, 54 in real-time.

12. The method of claim 11 further comprising the step of:

E. Communicating said specific load power and energy usage of each breaker 52, 53, 54 to a remote computer 70.