EP3189572A1

EP3189572A1 - System and method for switching an electrical system to backup power during a utility power outage

Info

Publication number: EP3189572A1
Application number: EP15716961.6A
Authority: EP
Inventors: David A. ELDRIDGE; Brandon J. Rogers; Maximilian A. Mueller; Ronald L. Thompson
Original assignee: Eaton Corp
Current assignee: Eaton Intelligent Power Ltd
Priority date: 2014-09-04
Filing date: 2015-04-06
Publication date: 2017-07-12
Also published as: CN106688155B; CA2959590A1; WO2016036419A1; CA2959590C; CN106688155A; RU2690008C1; BR112017003386A2; MX2017002146A; BR112017003386B1

Abstract

An apparatus (215) for managing an electrical system (200) includes a main breaker (220) structured to be coupled to a utility source (205), an LER breaker (240) structured to be coupled to a local generation source (245), a number of branch breakers (230), each branch breaker being structured to be coupled to one or more loads (235), and a control component (250). The control component is structured to, in response to a determination that the utility source is experiencing a power outage: cause the main breaker to be opened, determine which one or more of the number of branch breakers are to receive backup power from the local generation source, cause the branch breakers to be configured such that only the determined one or more of the number of branch breakers are in a closed condition, and cause the local generation source to be activated.

Description

SYSTEM AND METHOD FOR SWITCHING AN ELECTRICAL SYSTEM TO BACKUP POWER DURING A UTILITY POWER OUTAGE

CROSS-REFERENCE TO RELATED APPLICATION The instant application claims priority from U.S. Provisional Patent

Application Serial Number 62/045,864, filed September 4, 2014, the disclosures of which are incorporated herein by reference.

BACKGROUND

Field

The disclosed concept pertains generally to electrical distribution systems, and, more particularly, to a system and method for switching an electrical system, such as a residential electrical system, to a local generation source during a main utility source power outage that does not employ an automatic transfer switch or similar apparatus.

Background Information

A distributed power source, also sometimes referred to as a local generation source or a local energy resource, is a small-scale power generation mechanism used to provide an alternative to or an enhancement of the traditional electric power system. Distributed power sources include, for example and without limitation, photovoltaic (PV) modules (coupled to a DC/ AC inverter), wind turbine modules (coupled to a DC/ AC inverter), natural gas turbines, backup generators, energy storage, and uninterruptible power supplies.

When PV modules, generators and/or other local generation sources as just described are installed at a location, such as a residence, they are not allowed to produce power during a utility power outage unless they are isolated from the utility grid. This restriction is in place in order to prevent power from being back fed by the local generation source onto the grid during the power outage, a condition which could pose a danger to workers working on the grid.

Typically, this issue is addressed by employing a system 100 as shown in FIG. 1 that utilizes and automatic transfer switch (ATS) to ensure a safe transition to a local generation source during the power outage. As is known in the art, an ATS is an electrical switch that switches a load between two sources. As seen in FIG. 1, system 100 includes a utility source 105, a main meter 110, and a load center 115 coupled to main meter 1 10 for receiving power from the utility source 105. Load center 115 includes a number of conventional circuit breakers, including a

conventional main circuit breaker 120, a number of conventional branch circuit breakers 125, and a conventional local energy resource (LER) circuit breaker 130 (which is merely a conventional breaker coupled to a local generation source as described below). As seen in FIG. 1, conventional branch circuit breakers 125A and 125B are coupled to and provide protection for a number of "noncritical" loads 130 (i.e., loads that have been determined in advance to not be configured to receive backup power in the case of a utility power outage). The remaining conventional branch circuit breaker, labeled 125C, is coupled to an ATS 135 (or, alternatively, another switching device such as a manual transfer switch). The output of ATS 135 is provided to a sub panel 140 which in turn feeds a number of predetermined "critical" loads 145 (i.e., loads that have been determined in advance to be configured to receive backup power in the case of a utility power outage). In addition, system 100 includes a local generation source 150, which may be, for example and without limitation, a PV module coupled to an inverter, or any other suitable distributed power source. The output of local generation source 150 is provided to ATS 135 and to a grid tie disconnect 155. Thus, ATS 135 has two inputs, namely an output received from conventional branch breaker 125C and an output received from local generation source 150, and a single output which is selectable between the 2 inputs.

In operation, under normal operating conditions wherein utility source 105 is not experiencing a power outage, automatic transfer switch 135 is configured in a manner wherein the input received from conventional branch circuit breaker 125 is coupled to the output provided to subpanel 140. In addition, under such normal conditions, grid tie disconnect 155 is closed to enable local generation source 150 to back feed power to utility source 105. When utility source 105 experiences a power outage, grid tie disconnect 155 is opened in order to isolate local generation source 150 from load center 115 and utility source 105, and therefore protect any workers that may be working on the utility grid. Once grid tie disconnect 155 is opened, automatic transfer switch 135 may be switched to a configuration wherein the input received from local generation source 150 is coupled to the output provided to subpanel 140. As a result, during such an outage condition, predetermined critical loads 145 are able to receive power from local generation source 150.

While system 100 described above is effective, it introduces an extra layer of cost and complexity to the residential electrical system. Furthermore, system 100 is restricted in that it must be sized and configured in advance based on predetermined load profiles, namely the load profiles of certain predetermined loads that are to be powered by local generation source 150 during an outage. As will be appreciated, this eliminates any flexibility in determining which loads will be powered by local generation source 150.

SUMMARY

In one embodiment, an apparatus for managing an electrical system is provided. The apparatus includes a main breaker structured to be coupled to a utility source, an LER breaker structured to be coupled to a local generation source, a number of branch breakers, each branch breaker being structured to be coupled to one or more loads, and a control component. The control component is structured to, in response to a determination that the utility source is experiencing a power outage: cause the main breaker to be opened, determine which one or more of the number of branch breakers are to receive backup power from the local generation source, cause the branch breakers to be configured such that only the determined one or more of the number of branch breakers are in a closed condition, and cause the local generation source to be activated.

In another embodiment, a method is provided for controlling an electrical system that includes a main breaker provided in a load center and coupled to a utility source, an LER breaker provided in the load center and coupled to a local generation source, and a number of branch breakers provided in the load center and each being coupled to one or more loads. The method comprising includes determining in the load center that the utility source is experiencing a power outage, responsive to determining that the utility source is experiencing the power outage, causing the main breaker to be opened by providing first communication information to the main breaker, determining which one or more of the number of branch breakers are to receive backup power from the local generation source, causing the branch breakers to be configured such that only the determined one or more of the number of branch breakers are in a closed condition by providing second communication information to branch breakers other than the one or more of the number of branch breakers, and causing the local generation source to be activated by providing third communication information to the local generation source.

BRIEF DESCRIPTION OF THE DRAWINGS

A full understanding of the disclosed concept can be gained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings in which:

FIG. 1 is a schematic diagram of a prior art system that utilizes and automatic transfer switch to ensure a safe transition to a local generation source during a power outage;

FIG. 2 is a schematic diagram of a system for ensuring a safe transition to a local generation source during a power outage according to an exemplary embodiment of the present invention;

FIG. 3 is a flowchart showing a control methodology for the system of FIG. 2 according to an exemplary embodiment of the present invention;

FIGS. 4-7 are diagrams of an exemplary circuit breaker that may be employed to implement the system of FIG. 2 and the methodology of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Directional phrases used herein, such as, for example, left, right, front, back, top, bottom and derivatives thereof, relate to the orientation of the elements shown in the drawings and are not limiting upon the claims unless expressly recited therein.

As employed herein, the term "number" shall mean one or an integer greater than one (i.e., a plurality).

As employed herein, the statement that two or more parts are

"coupled" together shall mean that the parts are joined together either directly or joined through one or more intermediate parts.

As used herein, the term "component" is intended to refer to a computer related entity, either hardware, a combination of hardware and software, software, or software in execution. For example, a component can be, but is not limited to being, a process running on a processor, a processor, an object, an executable, a thread of execution, a program, and/or a computer. By way of illustration, both an application running on a processor or a server and the processor or server can be a component. One or more components can reside within a process and/or thread of execution, and a component can be localized on one

computer/processor and/or distributed between two or more computers/processors.

FIG. 2 is an electrical distribution system 200 according to one non- limiting, exemplary embodiment of the disclosed concept. As described in greater detail herein, system 200 includes a system of controllable (and in the exemplary embodiment, metering capable) circuit breakers including a main circuit breaker and a subset of branch circuit breakers downstream from the main circuit breaker. System 200 implements a control methodology (illustrated in FIG. 3 and described in detail in connection therewith) which enables a local generation source, such as, without limitation, a PV module coupled to an inverter, to be safely put into use during a power outage condition without the need to use an ATS, such as ATS 135 shown in FIG. 1, or similar switching device. As described in greater detail herein, in the exemplary embodiment, the control methodology determines when there is a utility power outage, isolates the load panel that is coupled to the utility grid, brings a local generation source safely online for as long as needed, coordinates load demand with local generation supply capacity , and restores grid power safely when the outage condition subsides. With respect to the coordination of load demand with local generation supply capacity, the methodology employs a control element wherein load demand is managed (i.e., loads are coupled to the local generation supply by closing associated breakers) so as to ensure that the load demand does not exceed the actual local generation supply capacity. The methodology may optionally employ synchronization among multiple local generation sources if provided and/or phase synchronization with grid power to allow for a seamless or "blinkless" transfer of power. As described in detail herein, this control methodology is accomplished by directly controlling the circuit breakers in system 200 rather than using a traditional switching mechanism such as an ATS. By tripping the main breaker, the load panel that is coupled to the utility grid can be isolated from the grid, and by switching a number of the branch circuit breakers on and off, the load demand can be balanced to match local generation supply capacity. In other words, the load's power demand can be controlled in order to prevent it from exceeding the power capacity of the local generation source. In practice, system 200 can dynamically determine the amount of local generation supply that is available from the local generation source (local generation source 245 described herein) and then coordinate with the other breakers (branch breakers 230 described herein) in system 200 to close only those breakers that can be supported by the local generation source without overloading.

In the non-limiting, exemplary embodiment of the disclosed concept, each of the controllable circuit breakers employed in system 200 as described herein is in the form of a power vending machine (PVM) circuit breaker 400 that is described in detail in the United States Patent Application Publication Nos.

2014/021 1345 and 2014/0214218 which are owned by the assignee of the present invention, the disclosures of which are incorporated herein by reference in their entirety. It will be understood, however, that the use of PVM circuit breaker 400 in the system 200 is for illustrative purposes only and is not limiting, as alternative types of controllable circuit breakers may also be employed. For example, and without limitation, one or more of the controllable circuit breakers employed in system 200 may be a smart breaker as described in U.S. Patent Application Serial No. 14/264,409, entitled "Microgrid System Structured to Detect Overload Conditions and Take Corrective Actions Relating Thereto", which is owned by the assignee hereof and which is incorporated herein by reference, or a remotely controllable circuit breaker having a second pair of separable contacts in series with the main separable contacts as described in, for example, United States Patent Nos. 5,301,083; 5,373,41 1;

6,477,022; and 6,507,255.

The exemplary PVM circuit breaker 400 is shown schematically in FIG. 4 and includes the following four types of functionality: (1) circuit protection functionality, including traditional thermal-magnetic circuit protection, short circuit protection, overload protection, ground fault protection, arc fault protection, and/or other types of protection as needed, (2) branch circuit metering functionality, including utility grade net metering (±0.2%) and time stamped values, (3) remote control functionality for operating controllable contacts, including on/off control relay functionality that is independent from the circuit breaker trip mechanism, (4) wired and/or wireless communications functionality, including functionality for transmitting and receiving meter control and status information, backup functionality for communications during an outage condition, and, optionally, load specific control features/signals which are configured to control particular types of connected loads (such as an electric vehicle supply equipment (EVSE) version of the breaker that can directly charge an electric vehicle (EV), a HVAC breaker that can directly and independently control the fan, compressor, and heating unit either directly through the opening and closing of the circuits or through low voltage signaling, essentially removing the need for a control thermostat, and a lighting control breaker that includes dimming capabilities; LER breaker 240 as described herein is another example wherein load specific control features may be employed to turn a connected local generation source on and off as needed). In the exemplary embodiment, functions (2)-{4) under the control of a microcontroller 401, which may be, for example and without limitation, a microprocessor or any other suitable processing device. In addition, while in the exemplary embodiment function (1) is not controlled by microcontroller 401, it will be understood that in alternative embodiments function (1) may also be under the control of microcontroller 401. Furthermore, in the illustrated embodiment, PVM circuit breaker 400 also includes indicator functionality (labeled (5)) controlled by microprocessor 401 to indicate information such as fault states and/or current flowing through PVM circuit breaker 400.

Before proceeding with a detailed description of the individual or elements and operation of system 200 according to the exemplary embodiment, the exemplary implementation of PVM circuit breaker 400 as shown in United States Patent Application Publication Nos. 2014/021 1345 and 2014/0214218 will be described in detail below with reference to FIGS. 5, 6 and 7.

PVM circuit breaker 400 can support billing a user for energy consumed through the PVM circuit breaker 400. For example, a metering function 402 (FIG. 5) uses a logic circuit 404 (FIGS. 5 and 6) to store timestamped energy values 406 in a persistent database 408 in memory 410. Both of the metering function 402 and the logic circuit 404 are within the housing of the PVM circuit breaker 400. The energy values 406, during certain timestamps, can be "flagged" as belonging to a number of specific users, which provides energy allocation to each of such number of specific users. For example, when the electric load 412 (shown in phantom line drawing)is plugged in, the energy can be suitably allocated to the specific power circuit (e.g., to electric load 412 (shown in phantom line drawing in FIG. 5) at terminals 414,416).

When an electricity source, such as an electric utility 418 (shown in phantom line drawing in FIGS. 5 and 6), which supplies power to breaker stab 420 (e.g., from a hot line or bus bar (not shown)) and neutral pigtail 422 (e.g., to a neutral bar (not shown)) at a panelboard or load center (not shown), is ready to bill the user, it can do so in a variety of ways through communication done via an expansion port 424 (FIG. 6), or optionally through a built-in wireless interface (e.g., without limitation, Wi-Fi; BlueTooth). One example method is a "meter read" of the total energy at the time of the reading from a main circuit breaker (not shown, but which can be substantially the same as or similar to the circuit breaker 400, except having a relatively larger value of rated current) of a corresponding panelboard or load center (not shown). The value of the "meter read" is compared with the value of the "meter read" from, for example, the previous month's reading and the difference value is billed.

Alternatively, the electric utility 418 can download the database 408 of each circuit breaker, such as 400, in its entirety, query the energy values 406 as appropriate, and then apply a suitable rate structure using the timestamps, specific circuits, and any allocation flags.

FIGS. 5-7 show the example controllable, PVM circuit breaker 400, which can include optional support for communications and/or a number of different add-on modules 426, as will be discussed.

Referring to FIG. 5, the example PVM circuit breaker 400 can include a number of optional add-on modules 426. An alternating current (AC) electrical path through the PVM circuit breaker 400 between the electricity source 418 and the load 412 includes a thermal-magnetic protection function 428, the metering function 402 and controllable separable contacts 430. An AC-DC power supply 432 supplies DC power to, for example, the logic circuit 404 and a communications circuit 434.

Alternatively, the DC power supply 432 can be located outside of the PVM circuit breaker 400 and supply DC power thereto. The number of optional add-on modules 426 can provide specific logic and/or I/O functions and a communications circuit 436. Optional remote software functions 438,440 can optionally communicate with the communications circuits 434,436.

FIG. 6 shows more details of the example PVM circuit breaker 400, which includes an external circuit breaker handle 442 that cooperates with the thermal magnetic trip function 428 to open, close and/or reset corresponding separable contacts 429 (FIG. 7), an OK indicator 444 that is controlled by the logic circuit 404, and a test/reset button 446 that inputs to the logic circuit 404.

In this example, there is both a hot line and a neutral line through the PVM circuit breaker 400 along with corresponding current sensors 448,449, voltage sensors 450,451, and separable contacts 430A,430B for each line or power conductor. A power metering circuit 452 of the metering function 402 inputs from the current sensors 448,449 and the voltage sensors 450,451 , and outputs corresponding power values to the logic circuit 404, which uses a timer/clock function 454 to provide the corresponding timestamped energy values 406 in the database 408 of the memory 410. The current sensors 448,449 can be electrically connected in series with the respective separable contacts 430A,430B, can be current transformers coupled to the power lines, or can be any suitable current sensing device. The voltage sensors 450,451 can be electrically connected to the respective power lines in series with the respective separable contacts 430A,430B, can be potential transformers, or can be any suitable voltage sensing device.

FIG. 7 is an example one-line diagram of the example PVM circuit breaker 400. Although one phase (e.g., hot line and neutral) is shown, the disclosed concept is applicable to PVM circuit breakers having any number of phases or poles. A hot line is received through the termination 420 to a bus bar (not shown). Electrical current flows through the first circuit breaking element 429 of the thermal-magnetic overload protection function 428 and flows through a set of controllable separable contacts 430 (only one set is shown in this example for the hot line) to the load terminal 414. A first current transformer (CT) 448 provides current sensing and ground fault detection with customizable trip settings. The return current path from the load 412 (FIG. 5) is provided from the load terminal 416 for load neutral back to the neutral pigtail 422 for electrical connection, for example, to a neutral bar of a panelboard or load center (not shown). A second CT 449 provides current sensing and ground fault detection with customizable trip settings. The outputs of the CTs 448,449 are input by the logic circuit 404, which controls the controllable separable contacts 430. The power supply 432 receives power from the hot and neutral lines. The logic circuit communications circuit 434 also outputs to a communication termination point 456 of the expansion port 424 (FIG. 6).

Referring again to FIG. 2, the elements of system 200 according to the non-limiting, exemplary embodiment will now be described. System 200 includes a utility source 205 coupled to a main meter 210. A load center 215 is coupled to the output of main meter 210 for receiving utility power from the utility grid of utility source 205 therefrom. Load center 215 includes a main breaker 220 coupled to main meter 210. In alternative embodiments, main meter 210 may be omitted, with load center 215 being connected directly to utility source 205. In any such alternative embodiments, the metering functionality may instead be provided by main breaker 220, which, as described below, is provided with such metering functionality.

Load center 215 further includes a main busbar 225 and a number of branch breakers 230 coupled to main busbar 225. As seen in FIG. 2, each branch breaker 230 is coupled to an associated load or loads 235. In the illustrated, exemplary embodiment, load center 215 feeds dedicated circuits, meaning that each branch breaker 230 feeds and is coupled to a single load 235 (each load 235 is not, however, necessarily a dedicated circuit). It will be understood, however, that this is meant to be exemplary only and that other configurations wherein non-dedicated circuits and/or a combination of dedicated circuits and non-dedicated circuits may also be employed within the scope of the disclosed concept. Load center 215 further includes an LER breaker 240 having a local generation source 245 coupled thereto. Local generation source 245 may be any type of distributed power source such as, without limitation, a distributed power source that employs a PV module, a generator, a wind turbine, a natural gas turbine, or battery storage.

In the non-limiting, illustrated exemplary embodiment, main breaker 220, branch breakers 230, and LER breaker 240 are each a PVM circuit breaker 400 described in detail elsewhere herein. Thus, each of those breakers will have circuit protection functionality, branch circuit metering functionality, remote control functionality and communications functionality as described herein (FIG. 4).

Furthermore, as seen in FIG. 2, load center 215 includes a control component 250. Control component 250 is structured to control operation of system 200 as described herein, and, in particular, is structured and programmed to implement the control methodology shown in FIG. 3 and described in detail below. Control component 250 may reside anywhere within load center 215, such as within main breaker 220, branch breakers 230, LER breaker 240, or may be spread among and distributed across one or more of those elements. In a an alternative embodiment, control component may be a computing device having a processor and a programmed memory that plugs into load center 215. In still a further alternative embodiment, control component may be remotely located from load center 250 yet still in communication with and in control of aspects of load center 250 as described herein. In the exemplary embodiment described herein for illustrative purposes, control component 250 forms part of main breaker 220 to enable main breaker 220 to act as a system coordinator for load center 215.

Referring to FIG. 3, the control methodology of the disclosed concept according to an exemplary embodiment will now be described. The method begins at step 300, wherein an outage at utility source 205 is detected. In the exemplary embodiment, this outage is detected by main breaker 220 by sensing that the voltage from utility source 205 has dropped below a certain predetermined level. Next, at step 305, control component 250 opens main breaker 220 to isolate load center 215 and local generation source 245 from the main grid of utility source 205. Then, at step 310, control component causes LER breaker 240 to be opened by communicating a control signal to LER breaker 240 (by a suitable wired or wireless connection).

Alternatively, the order of steps 305 and 310 may be switched such that step 310 is performed first followed by step 305. Next, at step 315, control component 250 identifies which ones of the branch breakers 230, if any, are to not receive backup power from local generation source 245. This step may be performed in a number of ways and includes determining which breakers are and which breakers are not to receive backup power based upon one or more stored and/or measured parameters and/or functions. For example, control component 250 may be programmed to identify certain predetermined ones of the loads 235 that are to receive backup power in the event of a power outage (i.e., "critical loads"), and thus at step 315, the loads 235 that are not "critical loads" will be identified. The programming and

identification of the "critical loads" in this particular implementation may be done by the utility and or the local user of load center 215, and thus this aspect of the disclosed concept provides great flexibility for the provision of backup power by allowing for dynamic load management during power outage conditions. The programming and identification of the "critical loads" may also be prioritized such that when an outage is detected, loads 235 will be selected to receive back up power based on the power that is available according to the predetermined priority. Alternatively, control component 250 may be programmed to dynamically select the ones of the loads 235 that are to receive backup power based upon predetermined parameters such as time of day and/or date, with certain loads 235 being identified for receiving backup power based upon the current state of such parameters. Furthermore, many additional alternative control schemas are also possible. For example, in one alternative control schema, each load 235 is identified in advance as "critical" or "non-critical", and control element 250 coordinates with metering data measured by the associated branch breaker as 230 to ensure that as many "critical" loads are operational without overloading/straining local generation source 245 (i.e., without exceeding the local generation source supply capacity). In another alternative control schema, each load 235 is assigned a priority level, with, for example, "1" being the highest priority and so on. Control component 250 then coordinates with metering data measured by the associated branch breakers 230 to ensure that as many of the highest prioritized loads 235 are operational without overloading/straining local generation source 245. Thus, the first example schema provided above is essentially a two-priority example of this second control schema. In still another alternative control schema, each load 235 is assigned a priority and a preferred "run time". Control component 250 then coordinates with metering data and time data to ensure that as many of the highest prioritized loads 235 are operational for their specified run times, and at the end of the run time of a load 235 other lower-prioritized loads 235 may have their associated branch breakers 230 closed. In yet another alternative control schema, control component 250 may implement any of the above schemas, with a "user override" component wherein the user may select particular branch breakers 230 to be opened and/or closed.

Following step 315, the method proceeds to step 320, wherein control component 250 causes the branch breakers 230B identified in step 315 to be opened. Next, at step 325, control component 250 causes a signal to be sent to local generation source 245 (using a suitable wired and/or wireless connection between those components) which causes local generation source 245 to be activated. Next, at step 330, control component 250 causes LER breaker 240 to be closed by causing a signal to be sent to LER breaker 240 (using a suitable wired and/or wireless connection between those components). Following step 330, the method proceeds to step 335, wherein system 200 is able to run on power from local generation source 245 with power being provided to any of the loads 235 that were not identified in step 315.

At step 340, a determination is made as to whether utility power at utility source 205 has been restored. If the answer is no, then the method returns to step 335. At this time, the user of load center 215 may reconfigure the system to change the branch circuit breakers 230 that are open (or closed) and thus the loads 235 that receive power using control components 250. For example, if during a power outage event, a user determines that they now need a load 235 that was originally determined "non-critical" or low priority, they can now close that circuit, and, if necessary, open another circuit of lower priority in order to prevent

overstraining the local generation source 240 (as described below). For instance, if a user determines that they need to recharge their EV that was originally determined "non-critical", they may choose to temporarily turn off their air conditioning unit in order to allow charging of their EV. Then, once the EV has sufficiently charged, the user may choose to turn the EVSE off and the air conditioning unit back on. This provides a substantial amount of extra flexibility and resiliency for the user that traditional systems cannot offer. Care should be taken, however, to manage/match the connected loads 235 so as to not overstrain the capacity of local generation source 245 and either tripping its back feed breaker or over straining it to the point of failure. In the exemplary embodiment, control component 250 includes control features to assist with the management and matching of loads 235 so as to prevent overstraining of local generation source 245. For example, before any changes are made, control component 250 can examine metering data and determine what effect the changes will have on load demand and prevent any changes that would result in an over straining condition. If, however, the answer at step 340 is yes, then the method proceeds to step 345 wherein control component 250 causes the LER breaker 240 to be opened. Next, at step 350, control component 250 causes local generation source 245 to be deactivated. Thereafter, at step 355, control component 250 causes main breaker 220 to be closed. Then, at step 360, control component 250 causes all of the branch breakers 230 to be closed by sending one or more signals to those branch breakers 230 (using a suitable wired and/or wireless connection between those components). Alternatively, the order of steps 355 and 360 may be switched such that step 360 is performed first followed by step 355. Finally, at step 365, control component 250 causes local generation source 245 to be activated so that it can return to back feeding utility source 205 now that the outage has been rectified.

Thus, the methodology shown in FIG. 3 and described above provides a safe mechanism for switching to backup power via a local generation source in the case of a power outage and back to utility power following the outage that does not require a cosdy, complex and inflexible switching mechanism such as an ATS (FIG. 1)·

Furthermore, while system 200 shown in FIG. 2 and the methodology described in connection with FIG. 3 include only a single local generation source 245, it will be understood that the disclosed concept may also be employed in systems that include multiple local generation sources 245 and multiple LER breakers 240. In such an alternative implementation, the methodology as implemented in control component 250 would need to ensure that the multiple local generation sources 245 are able to synchronize to each other. In one exemplary embodiment, one local generation source 245 would be promoted to become the "utility" and would be connected to a main bus bar 225. That local generation source 245 then provides the wetting voltage for other local generation sources 245 to synchronize to. In another alternative embodiment, control component 250 is provided with metadata about local generation source 245 for example, weather data for solar embodiments or fuel capacity in fuel consumption for generator embodiments, and metering data received from the branch breakers 230 may be used to predict "uptime remaining" for how long local generation source 245 can continue to provide power to the connected loads 235. Load management decisions can be made more intelligently with the addition of metadata from which important statistics may be derived, such as, but not limited to, "uptime remaining."

In still a further alternative embodiment, local generation source 245 shown in FIG. 2 may, rather than being provided at a customer location such as a residence, be a local generation source that is intended for a group of utility customers within an electrical distribution system (e.g., a "neighborhood" local generation source). For example, local generation source 245 may be a local energy storage device (e.g., battery) that is configured to serve a number of customers in a particular area in the event of a power outage. In such a configuration, one or more customers may have a load center 215 as described herein having an LER breaker 240 that is coupled to that "neighborhood" local generation source 245. Thus, as described herein, each customer having such a load center 215 can determine which loads 235 will receive backup power from the "neighborhood" local generation source 245 in the event of an outage. In addition, since main breaker 220, LER breaker 240, and branch breakers 230 are, in the exemplary embodiment, each PVM circuit breakers 400 as described herein having a metering functionality, the utility providing the "neighborhood" local generation source 245 will be able to bill the customers for their usage thereof. In one example, customer usage may be unlimited and customers will pay for any power that is consumed. In another embodiment, customers may subscribe for (and pay for) a certain amount of backup power in the case of an outage, and their access to the "neighborhood" local generation source will be limited to the amount of power covered by their subscription (i.e., the LER breaker 240 will be opened once the subscription amount of power has been consumed). In such a case, the customer may want to actively manage the loads 235 of load center 215 as described herein in order to ration the power to which they have access.

While specific embodiments of the disclosed concept have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the disclosed concept which is to be given the full breadth of the claims appended and any and all equivalents thereof.

Claims

What is claimed is:

1. An apparatus (215) for managing an electrical system (200), comprising:

a main breaker (220) structured to be coupled to a utility source (205); an LER breaker (240) structured to be coupled to a local generation source (245);

a number of branch breakers (230), each branch breaker being structured to be coupled to one or more loads (235); and

a control component (250), the control component being structured to, in response to a determination that the utility source is experiencing a power outage:

cause the main breaker to be opened;

determine which one or more of the number of branch breakers are to receive backup power from the local generation source;

cause the branch breakers to be configured such that only the determined one or more of the number of branch breakers are in a closed condition; and

cause the local generation source to be activated.

2. An apparatus according to claim 1, wherein the control component is structured to cause the LER breaker to be opened before determining which one or more of the number of branch breakers are to receive backup power from the local generation source and to cause the LER breaker to be closed after the local generation source is activated.

3. An apparatus according to claim 1 , wherein the main breaker, the LER breaker, and each of the branch breakers includes remote control functionality for operating controllable contacts thereof, communications functionality for transmitting and receiving information, metering functionality for metering an amount of power consumed therethrough, and circuit protection functionality including thermal- magnetic circuit protection.

4. An apparatus according to claim 1, wherein the control element is: (i) provided as part of the main breaker, (ii) provided as part of the LER breaker or one of the branch breakers, (iii) provided remotely from the main breaker, the LER breaker, and each of the branch breakers, or (iv) distributed over two or more of the main breaker, the LER breaker, and a number of the branch breakers.

5. An apparatus according to claim 1, wherein the control component is structured to cause the LER breaker to be opened after the main breaker is opened and wherein the control component is structured to cause the LER breaker to be closed after the local generation source is activated.

6. An apparatus according to claim 1 , wherein the control component is structured to, in response to a determination that power outage has ended, cause the LER breaker to be opened, cause the local generation source to be deactivated, cause the main breaker to be closed, cause all of the number of branch breakers to be closed, and cause the local generation source to be activated.

7. An apparatus according to claim 1 , wherein the control component is structured to determine which one or more of the number of branch breakers are to receive backup power from the local generation source based upon a stored, predetermined identification of the one or more of the number of branch breakers.

8. An apparatus according to claim 1 , wherein the control component is structured to detennine which one or more of the number of branch breakers are to receive backup power from the local generation source based upon a stored, pi^etermined prioritization of the of each of the one or more loads.

9. An apparatus according to claim 1 , wherein the control component is structured to determine which one or more of the number of branch breakers are to receive backup power from the local generation source based upon one or more predetermined parameters measured by, determined by, or received by the control component.

10. An apparatus according to claim 1, wherein the control component is structured to determine which one or more of the number of branch breakers are to receive backup power from the local generation source by selecting the one or more of the number of branch breakers in a manner that ensures that load demand through the one or more of the number of branch breakers will not exceed a supply capacity of the local generation source when the local generation source is activated.

1 1. An apparatus according to claim 1 , wherein the control component is structured to determine which one or more of the number of branch breakers are to receive backup power from the local generation source based upon a stored, predetermined priority assigned to each of the number of branch breakers.

12. An apparatus according to claim 1 , wherein the control component is further structured to ensure that a maximum number of the branch breakers receives backup power without exceeding a supply capacity of the local generation source when the local generation source is activated, and wherein the one or more of the number of branch breakers that are to receive backup power are determined based upon a stored, predetermined priority assigned to each of the number of branch breakers.

13. An apparatus according to claim 1 , wherein the control component is structured to determine which one or more of the number of branch breakers are to receive backup power from the local generation source based upon a stored, predetermined priority and a stored predetermined runtime assigned to each of the number of branch breakers.

14. An apparatus according to claim 1 , wherein the control component is structured to, during the power outage and after the local generation source is activated, enable the electrical system to be reconfigured by receiving an

identification of certain ones of the branch breakers that are to receive power and certain other ones of the branch breakers that are not to receive power and in response thereto cause the branch breakers to be configured such that only the certain ones of the branch breakers are in a closed condition.

15. A method for controlling an electrical system (200) that includes a main breaker (220) provided in a load center (215) and coupled to a utility source (205), an LER breaker (240) provided in the load center and coupled to a local generation source (245), and a number of branch breakers (230) provided in the load center and each being coupled to one or more loads (235), the method comprising:

determining in the load center that the utility source is experiencing a power outage;

responsive to determining that the utility source is experiencing the power outage, causing the main breaker to be opened by providing first

communication information to the main breaker;

determining which one or more of the number of branch breakers are to receive backup power from the local generation source;

causing the branch breakers to be configured such that only the determined one or more of the number of branch breakers are in a closed condition by providing second communication information to branch breakers other than the one or more of the number of branch breakers that are to receive backup power; and

causing the local generation source to be activated by providing third communication information to the local generation source.