U.S. patent application number 11/520900 was filed with the patent office on 2007-01-11 for method for adaptively managing a plurality of loads.
Invention is credited to Scott Robert Brown, Robert Joseph Dwulet, Alexander Filippenko, Andy Allen Haun, Mark John Kocher, Gary Myron Kuzkin, Julius Michael Liptak, Barry Noel Rodgers, Gary W. Scott.
Application Number | 20070010916 11/520900 |
Document ID | / |
Family ID | 34520153 |
Filed Date | 2007-01-11 |
United States Patent
Application |
20070010916 |
Kind Code |
A1 |
Rodgers; Barry Noel ; et
al. |
January 11, 2007 |
Method for adaptively managing a plurality of loads
Abstract
An intelligent power management system that includes a circuit
breaker containing a PLC module that spans open contacts of the
circuit breaker to provide a communication path for PLC messages
between the line and load sides of the circuit when the contacts
are open. The contacts are motorized to permit remote operation
through PLC messaging. Coupled to the PLC module is a controller,
which controls the opening and closing of the motorized contacts
under user control or via an adaptive load management algorithm
that reduces peak power consumption and adapts a set of loads to
changed power supply conditions. The controller can also
dynamically alter operational current and fault threshold levels on
a real-time basis based upon circuit requirements or environmental
conditions. The algorithm runs a state machine and also manages
loads in a limited power source environment such as when loads are
powered by a generator.
Inventors: |
Rodgers; Barry Noel;
(Raleigh, NC) ; Haun; Andy Allen; (Raleigh,
NC) ; Dwulet; Robert Joseph; (Wake Forrest, NC)
; Kocher; Mark John; (Raleigh, NC) ; Liptak;
Julius Michael; (Knightdale, NC) ; Filippenko;
Alexander; (Cary, NC) ; Brown; Scott Robert;
(Wake Forrest, NC) ; Kuzkin; Gary Myron; (Raleigh,
NC) ; Scott; Gary W.; (Mount Vernon, IA) |
Correspondence
Address: |
SQUARE D COMPANY;LEGAL DEPARTMENT - I.P. GROUP
1415 SOUTH ROSELLE ROAD
PALATINE
IL
60067
US
|
Family ID: |
34520153 |
Appl. No.: |
11/520900 |
Filed: |
September 14, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10972508 |
Oct 25, 2004 |
|
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|
11520900 |
Sep 14, 2006 |
|
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|
60513962 |
Oct 24, 2003 |
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Current U.S.
Class: |
700/295 |
Current CPC
Class: |
H02J 3/14 20130101; H02J
13/00009 20200101; H04B 3/54 20130101; H04B 2203/5483 20130101;
H02J 2310/12 20200101; H02J 13/00004 20200101 |
Class at
Publication: |
700/295 |
International
Class: |
H02J 3/00 20070101
H02J003/00 |
Claims
1. A method for adaptively managing a plurality of loads,
comprising: prioritizing, using a controller coupled to a plurality
of circuit breakers connectable to a respective plurality of loads,
at least some of the loads connectable to said circuit breakers
based on at least one criterion; and causing contacts of at least
one of said plurality of circuit breakers to be remotely moved
between an open position and a closed position based on said
prioritizing.
2. The method of claim 1, further comprising creating a set of
historical data reflecting a usage criterion of at least one
prioritized load.
3. The method of claim 2, further comprising predicting future
consumption of a load based on said set of historical data.
4. The method of claim 1, further comprising switching from a first
power source to a second power source different from said first
power source in response to a changed power supply condition.
5. The method of claim 1, further comprising storing a state of at
least one of the prioritized loads.
6. The method of claim 1, wherein a first load is an interruptible
load and a second load is a load having a high in-rush current
requirement, further comprising shutting down said first load to
provide additional power to start said second load.
7. The method of claim 1, further comprising establishing a
pre-determined set of loads which are turned on responsive to a
backup power source being switched on, and determining said
pre-determined set of loads based on at least a priority of a load
according to said prioritizing.
8. The method of claim 1, further comprising entering a limited
power source mode that maximizes the number of loads online while
maintaining the total consumed power under a pre-determined power
source limit.
9. The method of claim 1, further comprising: receiving an
indication of an adverse weather condition; and communicating a
signal to a controller of one of said circuit breakers to cause
contacts thereof to open thereby protecting loads connected to said
one of said circuit breakers from effects of said adverse weather
condition.
10. The method of claim 1, further comprising: connecting a
communications interface across contacts of one of said circuit
breakers such that said communications interface is connectable
between the line side and the load side of the circuit to which
said one of said circuit breakers is connected; and configuring
said communications interface to pass signals between the line side
and the load side regardless of whether said contacts of said one
of said circuit breakers are open or closed.
11. The method of claim 1, further comprising detecting which of at
least two states said contacts are in, said at least two states
being open and closed.
12. The method of claim 1, further comprising dynamically altering
a fault threshold level of one of said circuit breakers.
13. The method of claim 1, further comprising dynamically altering
an operational current threshold level of said circuit breaker.
14. The method of claim 1, further comprising dynamically adjusting
a trip threshold of said circuit breakers.
15. The method of claim 1, further comprising detecting an imminent
brownout condition on the line side of the circuit and, in response
thereto, causing contacts of at least one of said circuit breakers
to open.
16. The method of claim 1, further comprising predicting the
behavior of at least one of said loads using a neural network
predictor algorithm.
17. The method of claim 1, wherein said prioritizing and said
causing are carried out regardless of the source of a request for
changes in power supply conditions.
18. The method of claim 17, wherein said source is selected from
the group consisting of a utility power source, an alternate power
source, and a backup power source.
19. The method of claim 18, wherein said alternate power source
includes solar panels.
20. The method of claim 18, wherein said backup power source
includes a generator.
21. The method of claim 18, wherein said backup power source
includes an uninterruptible power supply.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a divisional under 35 U.S.C. .sctn.121
of co-pending U.S. application Ser. No. 10/972,508, filed Oct. 25,
2004, which claims the benefit of U.S. Provisional Application Ser,
No. 60/513,962, filed Oct. 24, 2003.
FIELD OF THE INVENTION
[0002] This invention is directed generally to power management
control systems, and more particularly, to an intelligent power
management control system.
BACKGROUND OF THE INVENTION
[0003] Circuit breakers have long been used in industrial and
residential applications to prevent damage to the loads connected
to them and the building structures in which the loads are located.
Normally, when an electrical fault or a current overload condition
is sensed in a particular circuit, the breaker protecting that
circuit "trips" and creates a physical disconnect in the circuit,
thereby preventing the flow of electricity. To resume electrical
flow to the circuit, the operator must physically reconnect the
circuit breaker, typically by throwing a mechanical switch back to
a closed position. These detection systems work automatically,
tripping circuits only when certain conditions are satisfied.
[0004] However, an energy supplier or consumer may want to control
energy flow deliberately to certain loads or circuits at such times
as are desired, even when no fault or overload condition is
detected. To do so, some way of remotely controlling the
connections across the loads must be provided. But in the case of
power line communication techniques, communication with any devices
on the load side of the circuit breaker cannot occur if it has been
tripped or if the electrical contacts inside the circuit breaker
are otherwise separated. Thus, as soon as a circuit breaker trips,
no further data can be collected on electrical devices connected to
that circuit breaker nor can any further instructions be
transmitted to change the behavior of the connected electrical
devices. There is therefore a need to maintain the communication
link from the utility or line side of the circuit breaker to the
load side of the circuit breaker even when the circuit breaker has
physically disconnected the branch circuit.
[0005] Another related need involves managing the loads or
electrical devices connected to circuit breakers within a home or
other facility in a way that is flexible and adaptable to both the
homeowner and the power company. Homes typically can obtain their
power from various sources, such as the power company, a backup
generator, or an alternative power source like solar power arrays.
Electrical devices (referred to as loads) within the home draw
varying levels of electrical power at different times of the day
and at different times of the year. Furthermore, electrical devices
can be categorized and prioritized based on their consumption
behavior (some loads cycle on and off throughout the day, other
loads draw lots of power when they turn on) and importance (a
life-saving medical device would be more critical than a swimming
pool motor). For example, an oven can be used year-round and most
frequently around dinnertime. An air conditioning unit can be used
heavily during the summer months and not at all during the winter
months. Data on the usage and properties of these and other
electrical devices throughout the home can be collected over a
period of time to create a set of historical data that reflects the
usage patterns, usage frequency, usage levels of each device, and
other properties about the electrical device.
[0006] During peak times in the summer months, the power company
may wish to limit or reduce peak power consumption. Other emergency
situations may call for a reduction or change in power consumption,
such as adverse weather conditions or utility equipment failure.
One approach to reducing power consumption is to initiate rolling
blackouts, but this inconveniences homeowners and renders entire
neighborhoods without power. What is needed, therefore, is an
adaptive load management algorithm that overcomes these and other
disadvantages. The present invention addresses this and other
needs, as more fully described below.
SUMMARY OF THE INVENTION
[0007] Briefly, according to an embodiment of the present
invention, an intelligent power load management and control system
and method and an adaptive load management algorithm are described
and shown. The system generally includes a circuit breaker that has
a communications interface (specifically a PLC module in some
embodiments) that spans the open contacts across the line and load
sides of a circuit such that the communications interface can still
communicate even when the circuit breaker is tripped or the
contacts are otherwise in an open position. The communications
interface can be adapted to interface messages compatible with PLC,
Ethernet, RS-45, or wireless schemes. The circuit breaker can
further include a DC voltage supply to supply power to the circuit
breaker components in the event of a trip event or loss of utility
power.
[0008] The circuit breaker contacts are motorized so that they can
be opened and closed remotely. A web server, optionally housed
within the circuit breaker, communicates with the controller to
cause the contacts to be opened or closed based on an adaptive load
management algorithm in a specific embodiment or other criteria in
other embodiments. The web server can also be configured to adjust
dynamically the operational current, fault, or trip threshold
levels of the circuit breaker. The adaptive load management
algorithm can predict the behavior of loads connected to the
circuit using a neural network predictor. The algorithm can also be
used to adaptively manage loads under limited power circumstances
when the circuit is being powered by a backup power supply, such as
a generator. The algorithm can be applied regardless of the source
of a request for changed power supply conditions--those sources can
originate from a utility power source, an alternate power source,
and/or a backup power source.
[0009] The foregoing and additional aspects of the present
invention will be apparent to those of ordinary skill in the art in
view of the detailed description of various embodiments, which is
made with reference to the drawings, a brief description of which
is provided next.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The foregoing and other advantages of the invention will
become apparent upon reading the following detailed description and
upon reference to the drawings.
[0011] FIG. 1 is a functional block representation of an exemplary
residential power distribution system;
[0012] FIG. 2 is a functional block diagram of a residential power
panel showing energy sources and load feeds according to an
embodiment of the present invention;
[0013] FIG. 3 is a functional representation of an intelligent
circuit breaker device according to an embodiment of the present
invention;
[0014] FIG. 4 is a functional block diagram of a residential load
management system and its components according to an embodiment of
the present invention;
[0015] FIG. 5 is a functional block diagram of a residential load
management system and its components according to another
embodiment of the present invention;
[0016] FIG. 6 is a state machine diagram of an adaptive load
management algorithm according to an embodiment of the present
invention;
[0017] FIG. 7 is a flow chart diagram of an adaptive load
management algorithm for managing loads in a limited power source
environment according to an embodiment of the present
invention.
[0018] While the invention is susceptible to various modifications
and alternative forms, specific embodiments have been shown by way
of example in the drawings and will be described in detail herein.
It should be understood, however, that the invention is not
intended to be limited to the particular forms disclosed. Rather,
the invention is to cover all modifications, equivalents, and
alternatives falling within the spirit and scope of the invention
as defined by the appended claims.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
[0019] Referring now to the drawings, and initially to FIG. 1, a
schematic representation of a residential power distribution system
100 is shown. A residence 106 is supplied power from an electrical
power utility 109, referred to herein as the power grid or power
utility source 110 through a utility power meter 132. Alternate
energy sources 112 can also be present in the residential
environment, such as solar panels 113, fuel cells (not shown), wind
vanes (not shown) or other methods of producing electrical energy.
Standby or backup power sources 114 can also be present such as
generators 115, storage batteries, or an uninterruptible power
supply, such as a UPS. Although a residential power distribution
system 100 is shown in FIG. 1, it is understood that the present
invention also applies to other types of power distribution
systems, such as industrial or non-residential power distribution
systems.
[0020] According to an embodiment of the present invention, the
power sources 110, 112, and 114 are connected to a power
distribution control panel 120. The power distribution control
panel 120 distributes electrical energy to various residential
circuits 150a-d. Each circuit is connected to the power sources
110, 112, and 114 through a protective device in the power
distribution control panel 120 such as an overload circuit breaker,
not shown here, but discussed in greater detail below. In various
embodiments, some or all circuit breakers to be managed by the
present scheme are coupled to or include a branch circuit meter to
provide data on the individual branch currents. Branch current
monitors (BCMs) commercially available from Veris Industries are
suitable (though not exclusively so) for this purpose.
[0021] The electrical circuits found within a residence or facility
106 are generally installed in a per-room and/or per-floor basis.
For example, as shown here for simplicity, the circuit 150b has
wall outlets for a specific group of rooms and the circuit 150a
supplies electrical power to lighting systems for a specific group
of rooms. In practice, lighting and electrical power outlets often
share a circuit and the associated protective circuit breaker
device.
[0022] Other electrical circuits that tend to be dedicated include
environmental equipment such as air conditioning 160, clothing
washers and dryers 162, heating, and audio-visual power circuits.
Specialized outdoor circuits for swimming pool, yard lighting, and
sprinkler systems can also be present in residential
environments.
[0023] According to an embodiment of the present invention, the
residential power distribution system 100 includes a power
management system 300 that has a web server 302 connected to an
internet service provider (ISP) by means of a conventional Internet
connection 308, e.g., cable modem, digital subscriber loop (DSL),
etc. The web server 302 is connected by a power cable 306 or other
network cable to a residential electrical power outlet from which
it draws electrical energy. The web server 302 conventionally
includes a controller.
[0024] A role of the web server 302 is to communicate messages
throughout the residential power distribution system 100. To do so,
the web server 302 sends and receives power line communication
(PLC) messages via a conventionally known PLC modem. Any
PLC-controllable or PLC-messaging devices connected to the
residential power distribution system 100 can communicate with the
web server 302, and can be controlled or monitored by PLC messaging
via the web server 302.
[0025] As mentioned above, the residential power distribution
system 100 can include alternate energy sources 112 or backup power
sources 114, which can supply power to the residence 106 if power
from the power utility source 110 is unavailable or diminished.
However, these types of power sources have reduced power capacity
as compared with the nearly infinite power capacity from the power
utility source 110, and therefore these alternate or backup sources
need to be used sparingly in order to prolong their ability to
supply power to the loads connected to them and to prevent
overloading the source. In the current state of the art, when
backup or standby power sources are used, they supply electrical
power via dedicated circuits within the residence or facility 106
to sensitive equipment such as medical equipment. To provide these
dedicated circuits requires rewiring or special wiring and leaves
the remainder of the residence or facility without power during a
loss of utility power. By employing the intelligent power
distribution system of the present invention, electrical power can
be made available to the entire house or facility 106 without
rewiring, and distributed electrical devices connected to the
electrical circuits can be controlled on a load basis through the
power distribution control panel 120.
[0026] Turning now to FIG. 2, a block diagram of the residential
power distribution center 100 from FIG. 1 is shown according to an
embodiment of the present invention. Electrical power from a power
utility grid 110 is connected to a utility power meter 132, which
is typically mounted on the exterior of a residence or facility 106
and is accessible to utility company personnel. Meters suitable for
the utility power meter 132 are typically called revenue meters and
are installed by the utility company. Meters suitable for user
meters 134, 136 and 138 include PM-850 PowerLogic.RTM. meters. An
isolator 126 can serve one or both of the following purposes:
first, it prevents PLC messages used within the residence or
facility 106 from being broadcast externally; and second, it
prevents PLC messages present on the utility power line from
entering the residence or facility 106. In other embodiments, the
isolator 126 is not supplied in order to permit communication
between the utility and the residence 106.
[0027] According to some embodiments, a user meter 134 is
accessible to the user and allows the user to track and monitor the
amount of electrical current and/or power used from the power
utility source 110 on a real-time basis. The amount of electrical
current and/or power from the backup power source 114 is monitored
by a backup power monitor 136. Power from the power utility source
110 and the backup power source 114 are coupled to a transfer
switch 133. The transfer switch 133 provides the user a way to
control the source of residential power, and is present only when
multiple power sources are available. Power from the transfer
switch 133 is routed to the power distribution control panel 120
through the main breaker 122.
[0028] According to another embodiment of the present invention, an
alternate power source 112, such as the solar panel array 113 or a
wind vane, is also present. The alternate power source 112 supplies
power to the distribution control panel 120 through another
user-accessible power meter 138, which allows the user to control
the output power level of the alternate power source 112. A
separate, alternate power meter monitors the amount of electrical
current and/or power delivered by the alternate power source
112.
[0029] According to yet another embodiment of the present
invention, a power quality monitor 140 monitors the quality of the
energy received from the power utility source 110 or backup power
source 114 and/or an alternate power source 112. Power quality
information is obtained from the power quality monitor 140 (or
monitors) via PLC messaging or meters 132, 134 and 138 via
conventional serial communications by the power management system
300 described below.
[0030] User access and control to the various devices mentioned,
e.g., the transfer switch 133, the backup power source 114 and/or
the alternate power source 112, the power meters 134, 136 and 138
as well as the power quality monitor 140 is accomplished, according
to an embodiment of the present invention, by means of power line
communication messaging. In other embodiments, user access and
control can be carried out using other suitable communications
messaging schemes, such as via Ethernet, RS-485, RS-232, Universal
Serial Bus (USB), or wireless schemes.
[0031] Turning now to FIG. 3, a functional representation of an
intelligent circuit breaker 200, according to an embodiment of the
present invention, is shown. The circuit breaker 200 is operatively
connected to a line conductor 202 and a neutral conductor 204. The
line conductor 202 has a line side 202a and a load side 202b. A
separate ground conductor 206 is also shown. A single pole breaker
200 is shown here as an illustrative example having contacts 210 on
the line conductor 202. In other embodiments, a double pole breaker
having breaker contacts for each phase load line can be utilized
for two-phase loads, such as clothes dryers 162, HVAC units 160,
pool pumps, and the like.
[0032] Part of the circuit breaker 200 operates similarly to
conventional circuit breakers. A conventional mechanical mechanism
(not shown) is used to set or engage the breaker contacts 210,
which allow current to flow through the load conductor 202. If the
circuit breaker 200 trips, i.e., opens the breaker contacts 210,
because of a detected overload or fault condition, the breaker
contacts 210 can only be reclosed manually by means of the
aforementioned mechanical mechanism and cannot be reclosed
remotely.
[0033] Current and/or fault sensing device(s) 226 are operatively
coupled to the line and/or neutral conductors 202 and 204 depending
on the type of current and/or fault sensing circuit used. The
sensing device(s) 226 and sensing circuit 222 are exemplary only,
and the configuration and deployment of these components is well
known to those of ordinary skill in the art. The sensing circuit
222 is connected to the sensing device(s) 226 and to a controller
220. According to an embodiment of the present invention, the
controller 220 is a micro-controller. According to another
embodiment of the present invention, the controller 220 is a
special-purpose integrated circuit. According to yet another
embodiment of the present invention, the current sensing circuit
222, shown here to be a separate function, can be integrated into
the controller 220.
[0034] A communications interface 224 is coupled to the controller
220 and optionally coupled to an optional 24 VDC source 232. The
communications interface 224 can, in alternate embodiments, enable
communications via PLC messaging, Ethernet, RS-485, or wireless
communications schemes. The communications interface 224 can be a
PLC module capable of handling PLC messaging schemes. The following
discussion assumes that the communications interface 224 is a PLC
module, however, it should be understood that the present invention
is not limited to such communication scheme. One of the problems
with PLC messaging is that when current state-of-the-art circuit
breakers are in the open position the communication link is broken.
To overcome this problem, the PLC module (communications interface
224) spans the gap to provide a communication path between the line
side of the circuit and the load side by means of power line
couplers 250a-d. The power line couplers 250a-d are positioned to
span the circuit breaker contacts 210 and to provide a
communication path even when the circuit breaker contacts 210 are
in the open or tripped position.
[0035] Signals from a messaging source on the load side 202b are
sent across power line coupler 250d through the communication line
252a to the communications interface 224. The communications
interface 224 passes the message signal out the communication line
252b through the coupler 250a to the line side 202a. Couplers 250b
and 250d and communication lines 254a and 254b are used for signals
passing in the other direction--i.e., from the line side 202a to
the load side 202b. According to another embodiment of the present
invention, the communications interface 224 is also a repeater,
used to boost the signal strength of the communication link between
the line side and the load side of the circuit. According to yet
another embodiment of the present invention, the communications
interface 224 is also connected to the controller 220 and thus acts
as a local modem. This connection allows for remotely communicating
with and controlling the controller 220 and thereby the circuit
breaker contacts 210, as well as accessing the state of the circuit
breaker 200 by means of PLC messaging. A message detected at the
load and line side of the contacts would indicated that the
contacts are in closed or in contact with one another. Signal
strength of the two signals could also be compared on line and load
side to access the open or closed state.
[0036] According to an embodiment of the present invention, an
AC-to-DC power supply 230 that is integrated with the circuit
breaker 200 provides DC power to the controller 220, the sensing
circuit 222, and the communications interface 224. The power supply
230 draws electrical energy off of the power lines 202a, 204
coupled to the circuit breaker contact 210. According to an
alternative embodiment of the present invention, DC power is
obtained from an optional 24 VDC power source 232 to supply power
to the circuit-breaker devices in the intelligent circuit breaker
200 as well as providing power for communication to other
components of the power distribution control panel 120 and uses an
uninterruptible power source to back-up the power to the optional
24 VDC power source 232.
[0037] Variations in the controller 220, the current sensing
circuit 222, and the sensing device(s) 226 can produce circuit
breaker devices with different operating characteristics or
combination of operating characteristics. These variations can
affect the conditions under which a fault or overload is detected
by the following devices within the circuit breaker: current
overload device, ground-fault circuit interrupter, or arc-fault
circuit detector.
[0038] When a fault or overload condition is detected, the
controller 220 energizes a conventionally known trip mechanism 212
such as a solenoid or other mechanism, which physically opens the
circuit breaker contacts 210. Using the intelligent circuit breaker
200, the operational current and fault threshold levels can be
altered on a real-time basis depending on circuit requirements or
environmental conditions. The alterations can include any of the
following and be carried out automatically or under user
control:
[0039] 1. Adjusting the GFI trigger levels. The intelligent circuit
breaker 200 can change the trip point, for example, from 5 mA to 30
mA depending on the application.
[0040] 2. Calibrating any sensing element, such as sensing
device(s) 226 to account for variations in the loads.
[0041] 3. Dynamically lowering or raising the trip threshold levels
of the intelligent circuit breaker 200 to account for variances in
the construction of various loads, for example. A load on a
dedicated circuit, such as a refrigerator, can be monitored over
time, and a new threshold can be established once a sufficient
amount of load data has been accumulated. The threshold levels can
also be set during the manufacturing process or during final
installation to account for variability of component material.
[0042] According to an embodiment of the present invention, the
controller 220 controls aspects of the power line communication. A
PLC module (communications interface 224) is connected to both the
line side of the power conductor 202a and the load side of the
power conductors 202b. This allows power line communication to
occur across open circuit breaker contacts 210, thereby permitting
access to PLC-capable devices connected to the load side of the
power conductors. It also allows PLC messages to be communicated to
and from the line side 202a of the contacts 210. In such a
configuration, an additional connection 256 from the communications
interface 224 to the neutral conductor 204 is required. According
to other embodiments of the present invention, the communications
interface 224 is incorporated into the controller 220 or special
purpose integrated circuit.
[0043] The intelligent circuit breaker 200 can be powered by a 24
volt DC source (shown generically as the AC-to-DC power supply 230
in FIG. 3) connected to the line side of the circuit and draws its
power from the un-switched line conductors 202a and 204 so that the
intelligent circuit breaker 200 remains powered even when the
circuit breaker contacts 210 are open. The AC-to-DC power supply
230 can be housed within the circuit breaker 200. According to
another embodiment of the present invention, the AC-to-DC power
supply 230 contained within the circuit breaker 200 also has an
uninterruptible power source, such as a battery or U.P.S., to
provide communication power during a power interruption. According
to another embodiment of the present invention, the optional 24 VDC
power source 232 exists to power the components of the power
distribution control panel 120. This 24 VDC power source 232 also
provides an uninterruptible power source to ensure PLC
communications. The 24 VDC power source 232 supports power line
communications even when the utility power is not in service and no
alternative or backup power 112, 114 sources is available.
[0044] Because the breaker contacts 210 are under control of the
controller 220, they can be opened or closed remotely (such as by a
conventionally known motorized mechanism) and without manual
intervention even when no overload or fault condition exists. An
example of such a circuit breaker is found within the G3
PowerLink.TM. motorized circuit breaker panel and also found in the
QOPL PowerLink# Circuit Breaker, although any other suitable remote
operable circuit breaker can be used. The breaker contacts 210 are
opened or closed in this manner by messages, such as PLC messages
or messages in Ethernet packets, from a central load management
system 300, such as the one described below in connection with FIG.
4.
[0045] In some embodiments of the present invention, the status of
the intelligent circuit breaker 200 can be queried by the load
management system 300 or similar residential control unit. The
expected statuses of the intelligent circuit breaker 200 include,
but are not limited to:
[0046] 1. Engaged, closed
[0047] 2. Disengaged, open, i.e., manually open, not
controllable
[0048] 3. Tripped, cause of trip (overload, fault, etc.)
[0049] 4. Open, i.e., commanded open and recloseable
[0050] FIG. 4 illustrates a functional block diagram of a load
management system 300 that depicts components of the power
distribution control panel 120. A power feed from the power utility
source 110 provides electrical energy to the power distribution
control panel 120. The isolator 126, on the utility power feed
line, prevents PLC or other communication signals from external
line-side sources from being broadcast internally and also prevents
internal load-side PLC or other communication signals from being
broadcast externally. The isolator 126 is particularly useful in
multi-dwelling units, preventing one unit from accessing or
controlling power levels to another unit. In embodiments where such
communication is desired, the isolator 126 is omitted. The backup
power source 114 supplies power to the distribution control panel
120 when power from the power utility source 110 is unavailable or
diminished. User-accessible meters 134 and 136 monitor the usage of
electrical energy of the utility power source 110 and the backup
power source 114, respectively.
[0051] Generally, the power distribution control panel 120 can, in
alternate embodiments, include any combination of a controllable
transfer switch 133, a surge protector 140, a main breaker 122, an
overload breaker 200a, a GFI breaker 200b, an AFCI breaker 200c,
and a 24 VDC power supply 232. The breakers 200a-c are connected to
electrical circuits 150, some or all of which can be protected by
the surge protector 140 in various embodiments.
[0052] The transfer switch 133 selects the source of electrical
power, such as utility or standby/backup power. In the event of a
utility power failure, the transfer switch 133 can switch the
source of electrical power from the power utility source 110 to the
backup power source 114. In a specific embodiment, the surge
protector 140 protects the entire residence or facility 100.
[0053] The circuit breakers 200a-c are not meant to represent an
exhaustive list. The circuit breakers have a mechanical, manual set
and reset mechanism, and an optional override switch. According to
an embodiment of the present invention, the functional state of the
circuit breaker is detectable. A partial list of such functional
circuit-breaker state information includes:
[0054] 1. Manual off
[0055] 2. Engaged
[0056] 3. Tripped
[0057] 4. Remote off.
[0058] The 24 VDC power supply 232 supplies power to various
components in the power distribution control panel 120 and enables
PLC message communication and remote operation of the circuit
breakers 200a-c. Although the 24 VDC power supply 232 is shown as a
separate block in FIG. 4 as supplying power to all of the
components in the distribution control panel 120, it can in other
embodiments be incorporated into individual components within the
control panel 120, such as in any one or more of the circuit
breakers 200a-c.
[0059] The dynamic load management system 300 further includes an
internet modem 314 coupled to an Internet Service Provider (ISP)
310, a firewall router 312, a web server 302, and a PLC modem 304.
In an embodiment, the web server 302 obtains power from a wall
outlet by means of a power cord 306 and is capable of sending power
line control (PLC) messages by means of the PLC modem 304 through
the power cord 306 to an electrical circuit 150. Alternatively, in
other embodiments, the web server 302 obtains its power from the 24
VDC power supply 232 optionally housed within the circuit breaker
200 or in the distribution control panel 120. Software running on
the web server 302 is responsive to user configuration and command
information to display a variety of electrical status information,
to control alternate power sources, and to limit power usage, such
as by carrying out an adaptive load management algorithm 600
described in connection with FIGS. 6 and 7 below. The power utility
company 109 can thus access the distribution control panel 120 over
the Internet via the user's ISP, allowing the power company to take
advantage of the existing infrastructure and technology without
having to reconfigure the power grid for use as a communications
network, although such reconfiguration is within the scope of the
present invention.
[0060] As noted above, although the present discussion refers to
PLC messaging, the present invention is not limited to PLC
messaging but rather contemplates other communication schemes such
as Ethernet, RS-485, or wireless communication schemes, to name a
few. For example, in an embodiment employing an Ethernet
communication scheme, the PLC modem 304 can be replaced by a
conventional Ethernet controller. Similarly, for a wireless
communication scheme, the PLC modem 304 can be replaced by an
802.11 wireless controller.
[0061] The Internet modem 314 can be any conventional Internet
modem, such as a cable modem, digital subscriber loop (DSL) modem,
or a wireless modem, to name a few. The ISP allows commands and
information to be communicated externally from the residence or
facility 100. For example, the user can access, monitor, and
control from a remote location via the ISP 310 the loads connected
to the electrical circuits 150 by logging into or otherwise gaining
access to the web server 302. In some embodiments, the web server
302 receives commands from the power utility 110 or passes messages
to the power utility 109. The power utility 109 has access to the
web server 302 through internet access across the user's firewall
312. In these embodiments, for example during peak power demand
periods or during emergencies, the power utility 109 can disable
certain electrical loads or initiate rolling blackouts to selected
loads connected to the power grid. By way of example only, during a
peak power demand, the power utility 109 can disable or cycle air
conditioning units or swimming pool motors in selected facilities
connected to the power grid 110 on a rolling basis by sending
appropriate messages via the Internet to each facility's web server
302, which in turn communicates a message to the appropriate
breaker in the distribution control panel 120 to remotely disengage
the contacts across the breaker to which the air conditioning unit
is connected thereby preventing that unit from receiving power.
[0062] To address "Big Brother" concerns, the user can allow or
disallow the utility company access to certain loads. For example,
to avoid the furnace motor from being cycled or turned off during
peak periods of electrical usage, the user can disallow remote
access to that load. Of course, the user can grant himself such
access, in case he leaves for an extended vacation and forgets to
turn the furnace off, for example, in order to save
electricity.
[0063] Utility companies can provide incentives for power reduction
in the form of rebates or other utility rate guarantees. For
example, users who sign up for a power reduction program and agrees
to grant the power utility company 109 remote access to the
distribution control panel 120 can receive rebates or a reduction
in the rate available to users who do not take advantage of the
program. Regardless of whether the power utility companies 109 have
access to the distribution control panel 120, the present invention
allows the user great flexibility in remotely controlling and
monitoring the loads connected to the control panel 120.
[0064] For example, the user can use dynamic load management to
limit the electrical power consumption by self-imposed limitations
based on occupancy, power consumption, power efficiency,
cost-of-power considerations, time-of-day or time-of-year pricing
and/or real-time pricing. When an alternate power source 112 is
present, it can be selected to supply part of the residential load.
According to another embodiment of the present invention, when an
alternate power source 112 is present power can be supplied
backwards onto the utility grid 110. The user meter 134, provides
the user with information on the amount of power fed onto the power
grid 110. The power meters 132 and 134 are also accessible to the
power utility 109 so that rebates, etc. can be applied to the
customer's account when excess electricity is so obtained.
[0065] The Internet-connected web server 302 can communicate with
weather forecasting services to protect against lightning damage
and other weather-related occurrences. Designated circuits, such as
those supplying electrical power to sensitive equipment, can be
shut down, unless overridden, to offer a further degree of
protection even when surge protection is used. This is especially
useful when the occupants are away from the residence or facility
100.
[0066] According to an embodiment of the present invention, when
there is a loss of power from the power utility source 110,
alternate power sources 112 or backup power sources 114 are
switched into the residence 100. When a standby or backup power
source 114, such as a power generator 115 is used, commands can be
sent over the PLC link to start the power generator 15. An
uninterruptible power source (not shown), which usually is a
battery or set of batteries, maintains the devices that use the PLC
link.
[0067] During utility power source 110 failures the backup power
source 114 is usually unable to supply all of the needs of the
residence. Therefore, a new set of user-configurable guidelines are
used to configure the dynamic load management system 300 based on
the capacity of the backup power source 114 or the alternate power
source 112 or a combination of local energy sources. Therefore,
according to an embodiment of the present invention, designated
circuits have a priority over non-designated circuits for power,
however, electrical power is still available to the entire
residence. Conventional systems utilizing backup power generally
run dedicated circuits to supply power to selected systems
requiring rewiring and a loss of power elsewhere in the
residence.
[0068] According to another embodiment of the present invention,
when there is a failure of the power grid such as a dangerous
undervoltage condition, there is an opportunity to protect
equipment using induction motors from brownout conditions by
turning off the designated circuits supplying such equipment. When
the brownout condition ceases, power can be restored by the dynamic
load management system 300. During excessive overvoltage
conditions, the loads can be similarly shut off to protect the
power distribution system of the residence or facility 100.
[0069] In FIG. 5, the configuration is the same as shown in FIG. 4
except that the web server 302 is incorporated into the
distribution control panel 120 in FIG. 5. The web server 302 in the
configuration shown in FIG. 5 can be powered by the AC-to-DC power
supply 230 or the 24 VDC power supply 232 optionally housed within
the distribution control panel 120.
[0070] To reduce peak power consumption and to accommodate an
existing set of loads to changed power supply conditions, the
present invention uses an adaptive load management algorithm 600
shown in state machine form in FIG. 6. The changed power supply
conditions can include: switching to the alternate power source 112
or to the backup power source 114, a request from power utility 109
to "shed" a load, etc. The adaptive load management algorithm 600
of the present invention preserves as much as possible the
functionality of the system. For example, household loads could be
rearranged to comply with changing power supply requirements and
still perform their functions if the available power supply is only
slightly lower than the demand. If the power demand increases, the
most important loads can stay online while the least important
could be disconnected. The decision to switch the load on or off is
made on the basis of the importance (priority) of the load, and/or
historical data regarding the load behavior gathered beforehand by
the dynamic load management system 300.
[0071] The adaptive load management algorithm 600 of the present
invention learns the behavior of the loads as well as the load
properties available for some loads in order to make the best guess
regarding the best load-control strategy. The algorithm is
preferably applied to residential installations, but could be also
used in any other installations. The same adaptive load management
algorithm 600 can be applied regardless of the power source,
whether it be the utility power source 110, the alternate power
source 112, or the backup power source 114.
[0072] Conditions of a limited power could arise during emergency
situations such as bad weather conditions resulting in power
outages, utility equipment failure, or higher electricity cost
hours. Usually a simple disconnection of "not important" loads is
used to comply with the restrictions. For example, an existing
practice is to shut down an HVAC unit when a power utility 109
requires "shedding" the load during peak hours. Or, in the case of
backup power source 114, a customer should chose a fixed,
non-configurable set of loads to be turned on, while all other
loads have to be shut down. Such selection normally has to be done
during construction, when the distribution control panel 120 is
installed. This inflexibility disadvantageously does not allow
post-installation dynamic reconfiguration of the loads.
[0073] Power usage by a load is not constant. Some loads are
cycling, like a refrigerator or hot water heater. Some loads
(kitchen range or lights) could be switched on or off manually.
Other loads have a significant in-rush current (air conditioning
units, for example), which could be prevented from starting when
the power source is unable to provide an overload current even for
couple seconds. An optimal managing of the loads in such conditions
is critical to keep as many loads functioning as possible.
[0074] To manage loads in the most flexible way, the
decision-making process can be improved by learning more about the
load-specific properties. For example, a refrigerator could present
a health hazard if disconnected for a long time, so special
attention is required for shedding it. The user also can apply a
beforehand knowledge and learned data to dynamically change a set
of loads that should be put on or off in each particular period of
time. For instance, a dishwasher scheduled for running at 11:00
p.m. could be easily rescheduled to 3:00 a.m., if necessary, but it
should not be shut down if it is already running. The same is true
for cooking. Shutting down the range in the midst of food
preparation to yield half-cooked food would ruin the meal.
[0075] Therefore, knowledge of the load properties, as well as its
previous state, should be used to select the best order and time
for running each load. The previous state is the state of the load
before it was shut down and could be determined by monitoring the
consumed power for a previous predetermined length of time. For
instance, the kitchen range would cycle on and off to keep burner
surface in a required temperature range. Thus, a zero immediate
consumed power does not necessary mean that the burner is off. It
could mean that the burner load is in an OFF part of the ON/OFF
cycle, and therefore could return to ON state at any time.
[0076] The types of loads are categorized according to any of the
following:
[0077] 1. Having significant in-rush current (HVAC, arrays of
incandescent lights, etc.)
[0078] 2. Interruptible or not interruptible: for example, a hot
water heater could be disconnected for a short period of time
without much inconvenience (interruptible), but it can be desirable
to have a TV set on all the time as long as it is being watched
(not interruptible).
[0079] 3. Cycling or not cycling load: a cycling load could share
the available power in different time slots, reducing the peak
power.
[0080] 4. Acceptable for long (e.g., hours) interruptions or not.
For example, a hot water heater could be disconnected for hours
during the daytime when hot water consumption is low (acceptable),
but a refrigerator must keep food cold and cannot be disconnected
for long periods of time (not acceptable).
[0081] Power sources are categorized by any of the following:
[0082] 1. Ability to tolerate an overload: High (such as the
utility power source 110), Low (such as the backup power source
114), and Zero (such as the alternate power source 112). This
category is important for starting the "high in-rush current" loads
like a HVAC compressor.
[0083] 2. Ability of the different power sources 110, 112, and 114
to work synchronously: a typical solar cell inverter (alternate
power source 112) can, while a low-cost emergency generator 115
(backup power source 114) normally cannot.
[0084] The adaptive load management algorithm 600 of the present
invention carries out several goals. First, it works with a
distribution system, such as the dynamic load management system of
the present invention, which includes:
[0085] 1. Load center (panel board) such as the distribution
control panel 120 equipped with either conventional (manual) and
controllable (motorized) or controllable only (and no conventional)
circuit breakers 200. One such suitable distribution control panel
120 is the G3 PowerLink.TM. motorized circuit breaker panel.
[0086] 2. Branch circuit meters such as the sensing circuits 222
provide data on individual branch currents. Exemplary branch
current monitors for this purpose are commercially available from
Veris Industries.
[0087] 3. A controller adapted to communicate with a network, such
as the web server 302. An example of such a server is a
PowerServer.TM. running Tridium-Niagara.TM..
[0088] 4. A network for communicating between the controllers,
meters, panels, some loads, and user interface, such as the
communications interface 224 and related interconnected devices
shown in FIGS. 3-4.
[0089] Second, the adaptive load management algorithm 600 of the
present invention provides a way to use a smaller size alternate
power source 112 for emergency or reduced energy consumption for
the house or facility 106.
[0090] Third, the adaptive load management algorithm 600 of the
present invention reduces (or "shaves") the power consumed by the
loads during peak periods. It does so by sequencing the
interruptible loads, briefly shutting down the interruptible loads
to provide extra power for starting "high in-rush current" loads,
or postponing the running of "low priority" loads. For example, a
dishwasher could be rescheduled to run at nighttime, when the
consumption is minimal.
[0091] Fourth, the adaptive load management algorithm 600 of the
present invention reduces energy consumed during the "high energy
cost" hours, as described above.
[0092] Fifth, the adaptive load management algorithm 600 of the
present invention provides a smart adaptive management of loads
when in restricted power mode (such as when power is supplied by a
backup power source 114, etc.) by at least any of the
following:
[0093] 1. Monitoring each load (branch) to collect (learn) data on
recent power consumption of the load to be able to predict possible
consumption if the load is online.
[0094] 2. If the utility power source 110 has been shut down
(because of an emergency or other reason), the adaptive load
management algorithm 600 turns all loads off and, after the backup
power source is on, turns a pre-calculated set of loads back on.
The pre-calculated set of loads is determined based on predicted
power consumption (calculated from historical data), the dynamic
priority of each particular load, and available power.
[0095] 3. Dynamically changes the list of loads with time according
to measured present power consumption, dynamic priority of each
particular load, and availability of power from the backup power
source 114.
[0096] 4. Maintains the dynamic list of active loads according to a
dynamic priority list, present state of the loads, and the power
available from the backup power source 114.
[0097] 5. Maintains the dynamic list of priorities for each
load.
[0098] 6. Manages switching of the loads ON or OFF by controlling
the load branches in the distribution control panel 120 using
controllable circuit breakers 200, or by communicating directly
with loads and instructing them to change the ON/OFF state if the
loads are capable for such a communication.
[0099] The adaptive load management algorithm 600 maintains a state
machine that switches the system into one of predefined states.
FIG. 6 shows a state machine diagram of an embodiment of a state
transition algorithm. Four states are illustrated: Full Power,
Shedding, Generator, and UPS. Each of these states will be
described next in further detail.
[0100] 1. Full Power state: the main power source (such as the
power utility 110) is running at full power and does not request
any restrictions. All loads are online. A "smart" algorithm can in
some embodiments be applied to make the cycling loads share the
same power using sequential time slots if possible to reduce peak
power.
[0101] 2. Shedding state: the main power source requests reducing
consumed power. Some less important loads are temporarily set
offline to reduce power.
[0102] 3. Generator state: the utility power source 110 is out of
service, so the system is powered from the alternative power source
112 (generator 115, fuel cell, etc.). The adaptive load management
algorithm 600 works to optimize the set of loads able to work with
the limited power supply (discussed in further detail in connection
with FIG. 7). A dynamic list of priorities is maintained for the
loads reflecting a possible state change of the loads.
[0103] 4. UPS state: the system is running on the backup power
source 114. Only the most critical loads are online. In this state,
the system waits until the backup power source 114 is online. If
the backup power source 114 fails to come online, the system has to
be shutdown.
[0104] Turning now to FIG. 7, the adaptive load management
algorithm 600 for managing loads in a limited power source
environment maintains a maximum possible number of loads online
while keeping the total consumed power under the power source
limit, Pmax. If the total load (Pload) is higher than a predefined
part A of Pmax (for example 95%), then a subset S of online loads
with lowest priorities and present total power consumption P is set
offline to reduce the total consumption to lower than predefined
part B of Pmax (for example 90%).
[0105] If the total load (Pload) is lower than a predefined part D
of Pmax (for example 60%), then a subset S of offline loads with
highest priorities and total estimated power consumption P is set
online to increase the total consumption. The subset S is defined
to increase the total consumed power to a level higher than
predefined part B of Pmax (for example 70%) and not higher than
part A of Pmax. It allows maximizing a number of loads able to work
with a limited power source.
[0106] Coefficients A, B, C, and D are selected with respect to the
following rule: 0<D<C<B<A<1.0.
[0107] Historical data is used to estimate a power consumption of
the loads that are supposed to be turned on. A load could cycle
and/or have a significant in-rush current, so if the load was not
consuming power just before being switched offline, it would be in
the OFF stage of cycling and would consume significant power if
suddenly brought online. Historical data would provide information
on expected consumption from that load, particularly if an in-rush
current is expected.
[0108] One difficulty in defining a correct set of the loads is the
unknown state of the load after it has been in the OFF state for an
extended period of time. While in the OFF state, the load could be
changed by customer. For example, someone could switch a burner of
the kitchen range on when the range was off, or the load can change
itself (such as in the case where a refrigerator detects a
temperature rise and tries to switch on). In both cases, the power
consumed by a load after some OFF period of time could be different
from power consumed just before it had been shut down. Therefore,
the power that would be consumed by the load if it were switched ON
needs to be estimated or predicted. A neural network predictor
could be applied to predict the behavior of the particular
load.
[0109] The adaptive load management algorithm 600 takes a maximum
steady (not in-rush) current observed earlier as estimates, and
defines a set of loads for putting online considering estimated
load, priority of the loads, and power supply sources 110, 112, or
114. Loads are then put online one by one with a short interval to
reduce step-load effect. If the resulting power is still under a
desired level, the process will be repeated until an optimal level
is achieved.
[0110] The adaptive load management algorithm 600 also assists in
starting up loads having a large in-rush current. To help to start
such a load, the algorithm 600 briefly, for a second or two, shuts
down all but the most important loads, starts the load in question
with a large in-rush current, and finally puts all recently
disconnected loads back online. This optional function can benefit
systems working in hot climate regions, where the inconvenience of
a brief shutdown of some devices would be much less important than
the ability to run an air-conditioning unit from a backup power
source 114, such as the generator 115.
[0111] Each state of the state machine of the adaptive load
management algorithm 600 can have its own algorithm for
initialization and operation. For example, the UPS state (FIG. 6)
begins operation by shutting down all load branches to prevent an
overload of the emergency power source 114 when it comes
online.
[0112] On entry, the Full Power state does not switch all loads ON
at the same time, but instead switches them ON one by one to reduce
step-loading of the utility power source 110 with a cumulative
in-rush current. The Full Power state collects the historical data
on consumed power for individual loads. It also communicates with
any available "smart loads" to reduce peak power by intelligent
scheduling or time-sharing.
[0113] The Generator state provides adaptive load management, or
allows the user to choose what set of loads can be ON when a backup
power source 114 is providing power. These sets could be predefined
by the user or by the installer.
[0114] The Shedding state can utilize a time sharing to comply with
a request from a power utility 109 for reducing consumed power.
[0115] While particular embodiments and applications of the present
invention have been illustrated and described, it is to be
understood that the invention is not limited to the precise
construction and compositions disclosed herein and that various
modifications, changes, and variations can be apparent from the
foregoing descriptions without departing from the spirit and scope
of the invention as defined in the appended claims.
* * * * *