CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority from a d claims th benefit of U.S.
Patent Application Serial No. 13/753,802, filed January 30, 20 which is
incorporated by reference herein.
This application s related to commonly assigned, copending United
States Patent Application Serial No. 13/753,793, filed January , 20 , entitled
"Annunciating or Power Vending Circuit Breaker for an Electric Load".
BACKGROUND
Field
The disclosed concept pertains generally to electric power distribution
and metering and, .more particularly; to electric power distribution systems that meter
electric energy. The disclosed concept further pertains to methods of evaluating
energy metering of an elec tric powe distribution system.
Background Information
Meters are used by electric utilities to measure and bil l for electricity
usage. Typically, meters need to be accessible, replaceable, testable and tamperresistant.
Meters need to be accessible and readable by both the utility and ts
customers to ensure correct meter readings. Meters need to be replaceable i the
event of a malfunction, and testable to ve rif accuracy. Also, a mechanism needs to
be provided to protect against theft of power or, otherwise, improper or inadvertent
bypassing or tampering of the meter, which results in inacc urate billing of actual
electricity usage.
Conventional glass bulb meters meet these requirements and are
accepted by public utility commissions due to their historical success in meeting the
above four needs in a cost effective manner. The glass bulb meter is a relatively
inexpensive, simple device used to accurately measure the energ kWh and peak
demand power ( W) within an agreed upon demand window used at a customer
premise. These meters were originally electromechanical devices, but are being
replaced b electronic meters. These meters are accessible, although not necessarily
private, since they are typically located on the outside of a building and are easily read
b anyone who walks up to them. Such meters are easily removed and replaced by
utility service personnel. Glass bulb meters can be beach tested using a know power
source and they are also protectable by using lockout tags to preve tampering.
Electric utilities are required by their public utility commissions to test
the accuracy of their meters. These tests normally follow the ANSI C 2 . ! and
ANSI/ASQ Z .9 standards. Typically, a statistical sampling plan is used to verify
meter accuracy. This statistical sampling pla states that the sample will, 95 times out
of 100, correctly determine whether at least 97.5% of a homogeneous lot of meters are
within th range of accuracy specified by the utility.
ANSI 2. allows other types of tests to verify metering accuracy
including a periodic test schedule and variable interval plan. These tests verify each
individual meter used b the utility. This is clearly a better practice for the utility and
its customers, however, meter deployments of most utilities are simpl too large for
this type of testing to be practical.
Automatic meter reading adds one-way communication, in order that a
meter can communicate bac to the electric utility office at regular intervals. Th s
improves accessibility because now the data can be made accessible over the Internet
or an appropriate, utility-owned communication network. Also, the electric utility no
longer has to send "meter reader" personnel to physically read each meter, since the
reading can be done automatically. The meter can also employ sensors, in order that
if there is some kind of malfunction or if t detects tampering, then it can send a
corresponding message to the electric utility.
Advanced meter infrastructure (AMI) or smart meter rollouts are
currently employed in various service territories. AMI adds two-way communication
between the meter and the electric utility. By adding the ability to 'listen" in addition
to being able to "talk", electric utilities can realize additional benefits. Variable time
of use schedules and real time pricing are two applications where the utility can
change how the meter is billing the customer based on the conditions of the utility
grid. Som smart meters have integrated service disconnects that can be triggered
remotely if the utility bill is not timely paid. These meters may also include
communication into the premise to communicate with end devices. This allows a
utility to perform demand response or load control and actively manage participating
loads on the utility grid. This e command functionality creates an additional metric
to value a meter. While the benefits have not yet been fully realized and standard
ways for end devices and the meter to communicate are still under development,
smart grid demonstrations across the country are proving the value created by
com and tunction 1it .
Electric vehicles (EVs) are a relatively new category of load o the
utility grid and represent a huge potential growth of electricity demand from the grid.
This is double-edged sword for utilities they want to sell more power; but want to
do so during off-peak hours. A recent report shows that the current generation asset
utilization in the U.S. is only about 47%. As a result generation capacity does not
need to be increased to support additional load, if power is consumed during off-peak
times.
EVs have an additional benefit of reducing C< emissions. This
improves air quality and reduces emissions. n places like California, this and the
success of EVs is very important. However, California has a counter-iniuitive, tiered
approach to selling electricity. As a customer buys more energy, punitive action is
taken against them, in order that the cost per kWf increases as usage increases. This
creates a dilemma. EVs put customers in a higher tier of elect c prices, but help to
reduce emissions and clean the air.
This situation has resulted in "utility grade sub-metering" in electric
vehicle supply equipment (EVSE). California wants to subsidize the energy used to
charge EVs, but currently takes punitive action against customers with electric
vehicles. The solution is that the EV becomes a "special load" with a .special rate
structure, such tha th consumer is encouraged to adopt the technology which i
mutually beneficial to both the utility and the consumer. As EV and other "special
loads" (e.g. on-site solar and wind generation; distributed energy storage; intelligent
appliances) are added to a premise it makes the utility's current methodologies for
metering less effective and less beneficial to both the utility and d e consumer. As a
result, this presents an opportunity for the public utility commissions to accept
alternative methodologies an form factors other than the current glass bulb meter.
This would allow metering and billing of every load differently and separate from one
another in a manner tha does make i mutually beneficial.
There is room for improvement ia electric power distribution systems.
There is also mom for improvement in ethod of evaluating energy
metering of an electric power distribution system.
SUMMARY
These needs and others are met by embodiments of the disclosed
concept. n accordance wit one aspec of the disclosed concept, an electric power
distribution system is for use with an electric power source. The electric power
distribution system comprises: a first device exchanging first electric power with the
electric power source, the first device being structured to exchange the first electric
power with a plurality of second devices and to meter first electric energy
corresponding to the first electric power; the plurality of second devices structured to
exchange the first electric power with the first device, each of the second devices
being structured to exchange second electric power as at leas t part of the first electric
power with a number of corresponding electric loads and to meter second electric
energy corresponding to the second electric power; and processor comprising a
routine structured to compare the metered first electric energy from the first device
with a sum of the metered second electric energy f m each of the second devices
an to responsively determine proper or improper operation of the electric power
distribution system.
As another aspect of the disclosed concept a method evaluates energy
metering of an electric power distribution system for use with an electric power
source, the electric power distribution system comprising a first device exchanging
first electric power with th electric power source, the first device exchanging the first
electric power with a plurality of second devices and metering first electric energy the
corresponding to the first electric power, the plurality of second devices exchanging
the first electric power with the first device, each of the second devices exchanging
second electric power as at least part of the first electric power with a number of
corresponding electric loads and metering second electric energy corresponding to the
second electric power. The method comprises: su ming the metered second electric
energ from each of th second devices; and comparing with a processor the metered
first electric energy from the first device with the summed metered second electric
energy from each of the second devices, and responsively determining proper or
improper operation of the metering first electric energy and the metering second
electric energy
BRIEF DESCRIPTION OF THE DRAWINGS
A full understanding of the disclosed concept can be gained from the
following descri ption of the preferred embodiments when read in conjunction with the
accompanying drawings in which:
Figure I is a block diagram of an eiectric power distribution system for
an electric power source i accordance with embodiments of the disclosed concept.
Figure 2 is a simplified block diagram of single-phase power vending
machine (PVK circuit breaker in accordance with an embodiment of the disclosed
concept.
Figure 3 is a relatively more detailed block diagram of the PV circuit
breaker of Figure 2 .
Figure 4 is a relatively more detailed block diagram of the EV add-on
module of Figure .
Figure 5 is a flowchart of a checksum function in accordance with
embodiments of the disclosed concept.
Figures 6A-6B form a relatively more detailed flowchart of a portion of
the checksum function of Figure 5.
Figure 7 is power vending machine load center including the
checksum function of Figure 5.
Figure 8 is a block diagram of a transformer and a plurali ty of load
centers including the checksum function of Figure 5.
Figure 9 s a block diagram of a transformer an a plurality of
transmission lines including the checksum function of Figure 5.
F tre 10 is a block diasram of communications for the load center of
Figure 7.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As employed herein, the ter "number" shall mean ne or an integer
greater than one (i.e. a plurality).
As employed herein, the ter "processor' shal mean a programmable
analog and/or digital device that can st re, retrieve, and process data; a computer; a
workstation; a personal computer; a microprocessor; a microcontroller; a
microcomputer; a centra! processing unit; a mainframe computer; a mini-computer; a
server; a networked processor; control electronics; a logic circuit; or any suitable
processing device or apparatus.
As employed herein, the term "load" shall mean a power-consuming
load and/or a power-generating load.
As employed herein, the term "power source" shall mean a utility grid
or another suitable electric power source that can send and or receive electric power.
As employed herein, the terms "exchange'*, "exchanging" and
derivatives thereof shall mean rece ing and/or sending. For example and without
limitation, when used in the context of exchanging electric power, this shall mean
receiving electric power for a power-consuming load and/or sending electric power
or a generator or power-generating load.
As employed herein, the statement that two or mo parts are
"connected" or "coupled" together shal 1mean that the parts are joined together either
directly or joined through one or more intermediate parts. Further, as employed
herein the statement that two or more parts are "attached" shall mean that the parts
are joined together directly.
The disclosed concept is described in association with single-pole
circ t breakers, although the disclosed concept is applicable to a w de range of circuit
breakers and other electrical devices, such as meters, having any suitable number of
poles.
Figure 1 shows an electric power distribution system 2 for an electric
power source 4 (shown in phantom ine drawing). The system 2 includes a first
device 6 exchanging first electric power with the electric power source 4. The first
device 6 is structured to exchange the first electric power with a plurality of second
devices 8 and to meter first electric energy corresponding to the first electric
power. The second devices 8 ar structured to exchange the first electric power with
the first device 6. Each of the second devices 8 are structured to exchange second
electric power as a least part of the first electric power with a number of
corresponding electric loads and to meter second electric energy corresponding
to the second electric power. A processor P) includes a routine structured to
compare the metered first electric energy from the first device 6 w th a su of the
metered second electric energy 4 from each of the second devices and to
responsively determine 2! proper or improper operation of the electric power
distribution system 2.
The first device 6 can be any upstream power distribution device up to
and including the generation source (e.g., electric power source 4) and the second
devices 8 can be plurality of any power distribution devices electricaliy connected
downstream of the first device 6 .
Exam e
The routine is further structured to notify an electric utility 20
corresponding to the electric power source 4 responsive to the determined improper
operation.
Example 2
Each of the first device 6 and the second devices 8 includes a metering
circuit (MC) 22 and 24, respectively.
Example 3
The routine is further structured to adjust the compare for at least
one of energy losses in power conductors 26 operatively associated with the second
devices 8 and expected errors in the metering circuits 22,24.
Example 4
The use of electric vehicles (EVs), and other "special loads" as
disclosed herein, presents an opportunity to change the form factor of a conventional
glass bulb utility meter. The disclosed concept can be used in connection with a
controllable, electronic circuit breaker 100 including metering 102 and
communication 134 functions along with support for a number of add-on modules 26
as shown with the example power vending machine ( M) circuit breaker (PVMCB)
0 of Figures 2 and 3. The remotely controllable PVMCB 00 and a utility grade
metering function are combined with electric vehicle supply equipmeni (EVSE) in the
example add-on module 200 (Figure 4).
The example PVMCB 0 provides branch circuit, utility-grade
metering within the circuit breaker. This allows the use of, for exa ple multiple
rates, schedules and prices, within the same premise. Furthermore it increases the
resolution of metering and exposes exactly where and when electricity s being used
(from which the "why" can be extrapolated). By embedding metering into a smart
circuit breaker, control and demand response for n n-c n cating or noncontrollable
end devices or emergency load shedding can a!so be performed.
In a PV V! pane or load center 400 (Figure 7), potentially every circuit
breaker n the panel, including the ain circuit breaker 402 (Figure 7), can be a
PVMCB. Each circuit breaker can communicate. One circuit breaker, such as the
mai circuit breaker 402, can perform the routine , which repetitively tests and
verifies the accuracy of the metering by ensuring that the incoming power matches the
outgoing power. n the eve t of failure, the pa el can automatical ly determine
which meter failed and notify both the customer a d the electric utility. This reduces
theft o f power by ensuring that power flowing into the panel is accounted for by being
sourced to specific branch power circuits.
Th example PVMCB . 0 can employ an suitable rating, number of
poles and frame size. Because it is electronic, protection is provided using software
functions (e.g., without limitation, ground fault; arc fault; combination; metering
accuracy), with or without the number of add-on modules 6. Power circuit
protection ca include overcurrent protection, short circuit protection, optional ground
fault protection, optional arc fault protection, optional overvoltage protection, and
optional iindervoltage protection. For E S applications, preferably sa automatic
and manual resetting with lockout is provided.
Electric metering with, preferably, up to utility grade accuracy (e.g.,
without limitation, ±0 2% in accordance with ANSI C-12.20 an IEC 687 can be
provided. The PVMCB 10 0 provides time-stamped val ues of both net energy (Waithours)
and peak demand (Watts) as calculated within a configurable window size and
reset at configurable time intervals. Also, other energy-related values are also
accessible and logged including voltage, current, power (being consumed by the load
or generated and fed into the circuit breaker panel), and time/clock.
The MCB 1 0 also includes an expansion port 1 4 (Figure 3) that
provides on/off control and communication. This permits th interface with a number
of add-on modules including status information, such as for example and without
limitation, o o tri pped fault reason. fault time, time until reset, number of
operations, serial number, clock, and firmware version.
The V CB 0 can replace a conventional glass bulb meter by
offering branch power circuit level metering a d two-way communication which
provides remote on/off control, status information, metering, and time of use
information back to the utility. Additionally, test points can be provided on each
circuit breaker or at single common point of the oad center or panelboard, which
can take a circuit breaker (or a grou of circuit breakers) out of service, run a known
amount of power through it, an verify the meter output. Hence, there is no need to
remove a circuit breaker and put it on a test bench. The testing apparatus could
optionally he embedded into t e load center and run the tests automatically.
In. a complete PVM pane or load center, the disclosed routine
verifies the metering function 102 (Figure 2) sub-system of each PV CB 100 by
comparing and verifying that the total or summed incoming energy matches the
total or summed outgoing energy as shown by Equation :
(£q. 1}
For an observable system in the real world. Equation 1 is expanded as
shown by Equation 2;
Eq. 2)
wherein;
¾ ¾ energy leaving the electric powe distribution system 2 that i not
directly accounted for or measured (e.g., without limitation, in an electric power
circuit, a primary contributor is the energy lost due to heating of power conductors
and the surrounding environment by ine or load current; and
Errors accounts for the fact that there are no perfect instruments and any
measurement will have errors in both accuracy and precision (e.g.. without limitation,
relatively good instruments have a relatively very low error, which may be negligible
but is always present to some degree).
For the PVM routine , Equation 2 is calculated as .follows. ¾ ¾is
the su of th incoming energy from an number of power sources. This can include
the mcoming energy from the utility grid and/or from any number of other electric
power generation sources la a circuit breaker panel, for example, this i -measured by
energy flowing through the ma PVMCB. is the sum of all outgoing energy to
any number of loads h a circuit breaker panel for example, this is the sum of all
energy flowing through all of the branch PVMCBs, such as for example and without
limitation, dedicated branch circuit breakers for VAC, washers and dryers, and nondedicated
circuit breakers for lighting and receptacles. ¾ is calculated through a
suitable software function (e.g., based on known meta-data characteristics and.
parameters, but potentially different for each installation; this coul be calibrated
during the initial installation to provide more accurate results; th on-going function
and processing could be stored in the mai circuit breaker/meter along with its initial
caiibration settings and parameters) based on current, voltage, power, energy, time
and known physical characteristics (e.g., without limitation, material composition;
conductor ratings an sizes). Through probability and statistics, this software
function can be confirmed as being a reliable solution. å rr¾r; is the sum of all
errors in the electric power distribution system 2. This could include known
measurement errors and errors in the software function for This could also be
implemented as a tolerance or an allowable percentage based error.
The routine , which constantly compares energy i and energy out,
fa s when Equation 3 is true:
¾ ³ , where « ~ å
E . 3)
When th routine fails, or optionally fails multiple cycles to prevent
false positives, the ut ity and the customer receive a notification. Ihe routine then
performs analytics to determine the failed meter. These analytics can include but are
not limited to: (1) searching for load events and comparing them with known load
signatures; (2) analyzing environmental patterns with typical oad use profiles; (3)
employing metadata; and (4) employing known failure modes.
Example
For example, searching for load events and comparing them wit
known load signatures can include searching for a power circuit of the electric power
distribution system 2 that has never previously pulled over 10 A, but is currently
reporting 50 A A load signature can include, for example, history prior failures,
typical power signatures and behavior, ti e of day, and use patterns.
Example
As another example, analyzing environmental patterns with typical
load use profiles, can include, for example, using cunent weather data that says it is
90 degrees outside, but t e air conditioning power circuit is not pulling any power.
As a result, the failure reported b the routine is likely caused by a faulty meter
associated with the air conditioning power c cuit.
Example
For metadata, power circuits can be tagged with for example, load
type, rated current, number of operating cycles, and installation date. For example, a
washing machine is tagged as not being a power generating source and the
corresponding metering circuit will not report sourced power from the washing
machine unless it has failed. As another example, a power circuit rated for 20 A will
not continuously allow 00 A to be pulled unless the corresponding circuit breaker
has fa ed.
As further examples, number of operating cycles and instal lation date
of the circuit breaker can be used to help the analytics ra k suspected failing metering
circuits. For example, based on field trials t can be learned that when a particular
circuit breaker reaches 10 years of age it has a corresponding, for example and
without limitation, 20% percent chance of failing. Similarly, one of the circuit
breakers that has gone through !0,000 operations in year may have experienced
relatively larger amount of fatigue than the others and is, therefore,, more likely to be
subject to failure.
For known failure modes, once devices are deployed to the field and
begin to fail these Mure modes can be analyzed and added to the analytics through a .
firmware update. For example, once PV'MCBs are built, tested, deployed, and
failures occur, the failures ca be studied and algorithms can be incorporated to better
detect such failures. For example and without limitation a flaw in a current or
voltage sensor used in the circuit breaker might be linked to relatively very rapid a d
repeated cycling of the circuit breaker. This newly found knowledge can be applied
to a firmware update to better detect the failure mode and, thus, the failed meter.
f the routine is able to determine the faulty meter to a
predetermined confidence, then the electric utility and customer will be notified.
If the faulty meter remains unknown, f it is allowed by the customer,
and if predetermined thresholds have not been reached fo various conditions (e.g.,
without limitation number of on. off cycles; total amount of time turned off (e.g.,
loads can be turned off i order to isolate the error, but there are certain loads that a
user may not want to be turned off for a extended period (e.g. , refrigerator; air
conditioner; washer/dryer), because f they are turned off, it could adversely affect
them; hence, the user ma allow the system to turn off the load to determine the error
as long as they are not off for longer than, for example, 5 minutes or whatever they
prefer)), then the routine ca cycle loads to gain additional information to be used
in the analytics. This cycle can continue until the faulty meter is determined or the
routine i 8 ceases to report a failure (e.g., the meter was replaced or the problem stops
happening).
Once the faulty meter s determined, the faulty meter power/energy can
be determined by the routine 18. This is given by Example 23 and Equation 4, below.
Exampjg.8
As will be discussed, below, in connection wit Figures 2 and 3 a
example single-phase PVMC 0 can bill a user for energy consumed through the
P MCB. For example, the metering function 2 (Figure 2 ) uses a logic circuit 104
(Figure 3) to store time-stamped energy values 06 in a persistent database 8 in
memory i 0. Both of th metering function . 02 and the logic circuit 4 are within
the housing of the P M circuit breaker 0 The energy values 106 during certain
t e-stamps, 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 2 (shown in phantom line drawing i Figure 2), such as an
EV, is plugged in, the energy can be suitably allocated (e.g., without li itation to the
EV's vehicle identification number (VIN) or to an D tag swiped to allow
charging, which will a ocate the energy to the corresponding user; to any number of
groups associated with the EV or the user). he PVMCB 100 also allocates energy to
its specific power circuit (e.g., to electric load 2 at terminals 1 ,1 6 (Figure 3)).
When an electricity source, such as an electric utility (shown in
phantom line drawing in Figures 2 and 3). which supplies power to breaker stab 20
(e.g., from a hot line or bus bar (not shown}} and neutral pigtail 2 (e.g., to a neutral
bar (not shown}) at a panelboard or load center (not shown), s ready to b ll the user, it
can do so in a variety of ways through conununication done via the expansion port
(Figure 3). 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 sa e as or similar to the PVMCB .0 , except having a relatively larger value of
rated current) of corresponding panelboard or load center (not shown). e value of
the "meter read" is compared with the value of the "meter read" from, for example,
the previous month's reading an the difference value s billed.
Alternatively, the electric utility 118 can download the database 8 of
each circuit breaker, such a 10 0 . in its entirety, query the ener values 6 as
appropriate, and then apply a suitable rate structure using the time-stamps, specific
circuits, and any allocation flags.
figures 2 and 3 show the example controllable, PVMCB 100, which
ca include optional support for communications and/or a number of different add-on
modules 2 6 , as will be discussed.
Referring to Figure 2, the example PVMCB 100 can include a number
of optional add-on modules 126. An alternating current (AC) electrical path through
the PVMCB 0 between the electricity source and the load 2 includes a
thermal-magnetic protection function 8, the metering function 2 and controllable
separable contacts 0. An AC-D power supply 2 supplies DC power to, for
example, the logic circui 4 and a communications circuit 34. Alternat ely , the
DC power supply 1 can be located outside of the PVMCB 00 and supply DC
power thereto. The nu be of optional add-on modules 6 ca pro vide specific
logic and/or I functions and a communications circuit 36. Optional remote
so are functions 138,140 can optionally communicate with the communications
circuits 134,136.
Figure 3 shows more details of the example PVMCB 0, which
includes an external circuit breaker handle 2 that cooperates with the thermal
ag etic trip function 8 to open, close and/or reset corresponding separable
contacts (not shown), an O indicator 44 that i controlled by the logic circuit 4.
and a test/reset button 46 that inputs to the logic circuit 04.
n this example, there is both a hoi Sine and a neutra l line through the
PVMCB 00 along with corresponding current sensors . 48, 49, voltage sensors
1 0, , and separable contacts .1 30A J 308 for each line or power conductor. A
power metering circuit 2 of the metering function 2 inputs from the current
sensors 148, 9 and the voltage sensors 0, . , and outputs corresponding power
values to the logic circuit 1 4 , which uses a timer/clock function 15 to provide the
corresponding time-stamped energy va es 106 in the database 8 of the memory
10. The current sensors 4 ,1 9 can be electrical I connected in series with the
respective separabie contacts 30A, 30B, can be current transformers coupled to the
power lines, or ca be any suitable current sensing device. The voltage sensors
1.50,151 ca be electrical ly connected to the respective power lines in series with the
respective separable contacts 0A 3 B can be potential transformers, or can be any
suitable voltage sensing device.
Figure 4 shows one example of the number of add-o modules 6 of
Figure 2, which can be an EV add-on module 200 The example module 200 adds a
hardware and software implementation of suitable EV communications protocol,
ground fault detection at relatively low thresholds, and control of the controllable
separabie contacts 30 (Figure 3). More specifically, the module 200 performs the
functions of SAE 3-1772 (for E A markets) or 1EC 62196 (for the rest of the world
or where applicable) and provides a pilot signal 202 (and an optional proximity signal
204) outputs an inputs in addition to interfacing an external user interface 206. The
module 200 controls the PVMCB 00 to perform proper power interlock and conform
to the appropriate standards. It allocates metering information into a plug session
history and ca perform analytic functions (e.g., without limitation, use limitation
based on energy; smart scheduling). The module 200 allocates the usage and billing,
for example, to a V N, which can be used to collect lost tax revenue from fue
purchases, enables throttling (e.g., controlling the rate of charge), and panel
coordination (e.g. coordination with other controllable V circuit breakers to
reduc or manage overall demand usage for an entir circuit breaker panel or utility
sen-ice) n order to prevent demand charges.
The module 200 includes a first conductor finger 208 for a first ho line
to the PVMCB 00, and a second conductor finger 210 for a second hot line or a
neutral to such PVMCB. The conductor fingers 208,210 are electrically connected to
respective terminals 2 2,2 4 for an electric load . These terminals can be used to
provide AC power into the EV connector (not shown). For a single-pole EV circuit
breaker, these are a hot line and a neutral. For a two-pole EV circuit breaker, these
ar two hot lines. Fo three-pole EV circuit breaker, these are three hot lines.
A number of current sensors , suc as current transformers, sense a
differential current for a ground fault protection circuit , which can output a fault
signal an other current information to a logic circuit 220. The logic circuit 220, n
turn, can communicate externally through a communication circuit 222 to a first
expansion port 224 e g., without limitation, to provide a trip signal to the PVMCB
0) and/or a second expansion port 226 to communicate with othe local or remote
devices (not shown).
The logic circuit 220 also communicates with a memory 228 and the
external user interface 206, which can include a number of indicator lights 230 and a
reset button 232. n support of various EV interface functions, the logic circuit 220
further communicates with a DC, PWM output a d sensor fi ra ctio.r 234 that interfaces
the pilot signal 202 at terminal 236 and an optional proximity circuit 238 that
interfaces the optional proximity signal 204 (or proximity resistor (not shown)) at
terminal 240 for an [EC style EV add-on module. The module 200 also includes a
ground pigtail 242 that provides a ground to a ground terminal 244.
The example module 200 can he employed with the PVMCB [00 or
an suitable circuit breaker disclosed herein that feeds a suitable electric load.
Example protective functions performed b such circuit breakers can include
overcurrent, ground fault, overvohage. load interlock and/or a safe automatic reset.
Exa p e control functions include interfaces to the module 200. a suitable algorithm
for the load (e.g., EV) and state management for the oad (e.g., EV).
Example authentication functions performed by the module 700
include verification of permission to access power or control of the circuit breaker
(i.e., ve di g power to a load either locally or remotely, an additional logic and
interlock settings. As an example, these include determining whether you are allowed
to use power for the load (e.g., to charge an EV). or determining f you are an
administrator allowed to control the circuit breakers.
Example allocation functions performed by the PV CB 0 -include
tracking energy usage by department, circuit or user, limiting the amount of energy
usage, and utility grade energy metering e.g., 0.2% accuracy of metering energy).
Example optional an additional protection and control functions that
can be enabled i the PVMCB 100 b the module 200 include interchangeable
communication interfaces, remote control an additional trip curves.
Example 10
The remote software 40 of Figure 2 can be a checksum function 300, as
show in Figure 5. Fo example and without limitation, the example checksum
function 300 can be executed as part of a PVMCB 402 (Figure 7), which can be
similar to the PVMCB 100 of Figures 2 and 3, for a plurality of branch circuit
breakers, such as the PVMCB 100 of Figures 2 and 3 or the PVMCBs 404 of Figure
First, at 301, a checksum, such as wa disclosed, above, in connection
wit Equation 2, is executed. For example, the PVMCB 402 (Figure 7) main circuit
breaker (not shown) can collect time-stamped energy values from the branch
PVMCBs 404 (Figure 7 } for comparison th its locally collected time-stamped
energy values. For particular time-stamp (e.g., without limitation one second
intervals; any suitable time range), the various energy-in time-stamped energy values
are compared with the various energy-out time-stamped energ values using, for
example. Equation 3, at 302. If there is no failure at 302, then 301 is repeated for the
next time-stamp. On the other hand, if there is a failure (e.g.. Equation 3 is true), then
at 304 the electric utility and the electric power customer are notified of the failure.
Next, at 306, an analysis is performed to determine the failed "meter" (e.g., the failed
PVMCB 0 or metering function 2 of Figure 2; the a t circuit breaker; one of
the branch circuit breakers), as will be discussed in greater detail below, in
connection with Examples - and 32.
f a failed "meter" is determined at 308, then th electric utility and the
electric power customer are notified of the location of the failed meter and energy is
allocated appropriately at 310, as will be discussed in greater detail, below, in
connection with Example 23 and Equation 4.
Otherwise, if the failed ".meter" is not determined at 308, the at , it
is determined if the customer allows cycling loads and if load cycling limits are not
yet reached f so, then at 3 , a number of loads are cycled in order to search for the
failed meter before execution resumes at 306.
On the other hand, if the customer does ot allow cycling loads or i
the load cycling limits are reached at , then at , the checksum function 300 is
unable to determine the failed meter location, and th metering function 2 (Figure
2) continues to time-stamp metering information (e.g. , without limitation, power
values; energy values) to recover after the failed meter location is known.
Example I
At 302, the checksum function 300 can determine a predetermined
plurality of consecutive occurrences of the failure of Equation 3 before responsively
notifying at least one of the electric utility and the customer at 304,
Example
At 302, the checksum function 300 can determine a predetermined
number of consecutive occurrences of the failure of Equation 3 before responsively
notifying at least one of the electric utility and the customer at 304.
Example 13
At 306, the checksum function 300 can determine which one of the
PVMCBs fa ed by comparing a number of stored load events in the PV CB
database 108 (Figure 3 with a plurality of predetermined load signatures. For
example, at or about the time-stamp for the failure of the checksum function 300. if
the stored load event is quite different than th predetermined load signatures, then th
corresponding PVMCB is likely the failed "meter". See, also, Example 5.
Example 4
At 306, the checksum function 300 can determine which o e of the
PVMCBs failed by evaluating temperature versus time i fo rmatio a d energy versus
time infomiation for a number of the branch PVMCBs. For example, at or about the
time-stamp for the failure of the checksum function 300. if the outside temperature
was relatively quite high and the energy versus time information was about zero for
one of the branch PVMCBs associated with a air conditioner load, then thai PVMCB
is likely the failed "meter". See, also, Example 6.
Example
At 306 the checksum function 300 can determine which one of the
PVMCBs failed by evaluating at least one of: ( ) expected energy versus time
information, power source or power sink with actual energy versus time information;
and (2 load type or rated current with actual current versus time information, for a
number of the branch PVMCBs, See, for example, Example 7.
Example 1
Figures 6A-6B show a relatively more detailed flowchart of steps
306,308,3 0 , 4, 6 of the checksum function 300 of Figure 5. The goa l is to
accurately determine which meter failed, notify the electric utility and the customer
(e.g. premise) determine if accurate metering information i still possible, and make
it available, all with minimal power interruption.
f the checksum function 300 fails at 302 of Figure 5, as shown at 8
of Figure 6B, then the PVMCB with the failed "meter" is identified. At 320, it is
determined if a power circuit just begin pulling power or experienced a .relatively
large change in power. f so, then at 322, that power circuit and the corresponding
PVMCB are flagged as being the likely error. Next, at 324, i is determined if the
load for that power circuit historically turns itself off in a reasonable predetermined
amount of time. If not then at 326, the corresponding PVMCB is turned off for a new
checksum test at th next time-stamp. On the other hand, if the load for tha power
circuit does historically turn itself off in a reasonable predetermined amount of time.
then at 328, either wait for the load to turn itself off or if the predetermined amount of
time elapses, then the corresponding PVMCB is turned off for a ne checksum test at
the next time-stamp. Next, after 32 or 328, at 330, i i determined if the checksum
passed for the next time-stamp. f so. then at 332.. the PVMCB with the failed
"meter" is identified. Finally, at 334, the customer (e.g., facility manager;
homeowner) and the electric utility are notified which "meter" failed, and if any
reliable meter source remains (as will he discussed, below, in connection with
Example 23) or if immediate replacement of the failed "meter" needed.
On the other hand, if the power circuit did not just begin pulling power
and did not experience a relatively large change in power at 320, or the checksum
did not pass at 330, then beginning at 336, steps are taken to determine the most likely
failed meter. Here, power circuits with no load provide no information, unless th
routine 306 was waiting (e.g., if a load is historically cyclical in nature and it is
predictive as to when it should turn on/off. then the function 300 can wait for when
that load s anticipated to turn on before it tries to determine whether or not i is at
fault) or unless it was just turned off (e.g., steps 326, 328 or 340) and can be
determined to be the cause of the problem. The likely failed meter is determined, for
example and without limitation, by a variance in power, by whe the last major spike
(on or off) in power occurred, historical power trending and/or other possible inputs.
Next, at 338, it is determined if the PVMCB meter, as was determined
at 336, is reading power flow in a different direction than is valid (e.g., the meter for a
dedicated branch PVMCB for a power-consuming load, such as I AC, is showing
power generation in error). If so, then the PVMC B with the failed "meter" is
identified at 332.
On the other hand, if the power flow s in the correct direction at 338,
then at 340, th PVMCB meter, as was determined at 336, is toggled off at 340. Next,
at 342, it is determined if that PVMCB meter, as was determined at 336, is still
reading non-zero power. If so, then the PVMCB with the failed "meter" is identified
a 332.
On the other hand, if zero power was read at 342, then at 344 it is
determined if a new checksum test at the next time-stamp passes at 344. f so, then
the PVMCB with the failed "meter" is identified at 332.
On the other hand, if the checksum test failed at 344, then at 346 it is
determined if all branch PVMCBs are verified. f not, the execution resumes at 336
with the next most likely failed meter.
Otherwise, if all branch PVMCBs are verified at 346 then if the main
PVMCB energy is low relative to the of the energies of all of the branch
PVMCBs. the it i identified as the failed "meter" at 348. Otherwise, at 348, if the
main PVMCB energy s h gh relative to the sum of the energies of all of the bra ch
PVMCBs, then tt. s identified as the failed "meter" or the premise is identified as
having power theft at 348. Finally, after 348, step 334 i executed to suitably notify
the customer and the electric utility a was discussed above.
At either 346 or 348, it is also possible that multiple eters or
PVMCBs failed simultaneously. However, this s believed to b relatively very rare
occurrence and is not easily identified without turning the power off multiple times.
Genera y, the checksum function 300 cannot detect and treat multiple simultaneous
failures with absolute certainly. However, there are certain situations where a
simultaneous failure can be indicated as being suspected
l 1?
Other possible places to use the checksum function 300 include, for
example and without limitation, at a generation site, an within transmission lines.
The checksum function 300 can also be employed to help electric utilities locate
power "leaks" (e.g.. places where power is "leaking" or lost for example, to ground;
places where a conductive power bus or power line material is failing, increasing
resistance and heating up excessively). Here, power is not necessarily being stolen
but electric utility resources are being lost or wasted.
Example S
Figure 7 shows a .power vending machine (PVM) oa center 400
including a main. PVMCB 402 having the checksum function 300 of Figure 5. The
PVM load center 400 also includes a plurality of branch PVMCBs 404. The branch
PVMCBs 404 can generally be associated with piurality of power-consuming loads
406. However, it is possible that a number of the branch PVMCBs 404 can be
associated with a generation source, such as 408, or with an EV (with vehicle to grid
support) .
For example, an EV contains a battery or other suitable stored energy
medium h a normal application, the EV battery i charged from the grid and is
therefore consuming power. However, there are applications where the EV battery
could also supply power to a home by converting the stored e ergy back to A power
and act essentially like a generator in an emergency situation (this i also sometimes
referred to as reverse power flow). As a result, the EV is unique in that it can serve as
both a consumer and generator of power. There a e also applications where utilities
are a a simple battery ba k as distributed energy storage to do the same thing
except without the actual vehicle. In addition to e ergenc usage, it can also be used
where it charges the battery at night (during utility off-peak hours when rates a e
relatively cheaper) and then discharges during the day (during utility on-peak hours
when rates a e relatively more expensive).
Generally the main PVMCB 402 receives power 4 from the utility
grid 4. However, with the generation source 408, for example, it is possible that
the main PVMCB 402 can source power 4 to the utility grid 4 . m Equations 2
and 3, power 4 fr o the utility grid 4 corresponds to a positive value of E and
power 416 to the utility grid 4i4 corresponds to a negative value of l¾.
Similarly, for the branch PVMCBs 404, power flowing to the loads
406 corresponds to a positive value of and power flowing from the generation
source 408 back toward the utility grid 4 corresponds to a negative value of E
Example
The main PVMCB 402 includes a communication circuit 4 and/or
36 (Figure 2) structured to receive information from the branch MCBs 404 and
communicate the information to a re ote location, such as 0 (Figure 2). This
information can include, for example and without limitation, an identification of trip
status an time of trip for each of the branch PVMCBs 404, an an identification of
trip status and occurrence of a predetermined power signature for each of the branch
PVMCBs 404. The branch PVMCBs 404 similarly include a communication circuit
34 and/or 6 (Figure 2 ) structured to send such information to the main PVMCB
402. Figure shows one example of communications between the various PVMCBs
402,404, and the add-on modules 200,200 for the PVMCBs 404.
Example 20
Similar to Example , the main PVMCB communication circuit 1 4
and/or 6 (Figure 2) can he structured to receive an open or close command from the
remote location and communicate the open or close command to a corresponding one
of the branch PVMCBs 404 using their corresponding co u icatio circuit
and/or 6 (Figure 2).
Example
The disclosed concept ca be directed to for example, a panel o
PVMCBs, including the main PVMCB 402 and branch PVMCBs 404 as are shown in
Figure 7. This provides the checksum function 300 (Figure 5) that can verify hilling
accuracy and notify an electric utility in the event of theft or insufficient billing of
electric power. Alternatively, the checksum function 300 can be applied in other
areas, such as between transformer 502 and a plurality of downstream load centers
504,506,508 as are shown n Figure 8.
Example 22
The PVMCB checksum function 300 can be applied to applications
other than load centers or panelboards. This function 300 can prevent theft of power
and automatically verify the accuracy of meter readings anywhere in an electric power
distribution system.
Example 2
n Figure 7, energy flows inside the example PVM load center 400.
Power can flow in either direction and the disclosed function 300 still works correctly.
n addition to ver ication if a single meter fails and is identified, the PVM load
center 400 can still correctly allocate energy usage to each individiia! branch PVMCB
404 (including the branch power circuit of th failed PVMCB) by employing
Equation 4;
( q. 4)
wherein;
$ ¾ » i i ¾ inaccurate energy reading from a failed
PVMCB that must be remo ve from Equations 2 and 3; and
¾ k i the actual energy flowing through the failed
PVMCB.
As was discussed, above, in connection with Figures 6A-6B, the routine 306 allocates
a plurality of time-stamped energy values for a predetermined time period to one of
the PVMCBs 402,404 that failed after the failure of the checksum function 300 at 302
(Figure 5) or (Figure 6B).
Equation 4 assumes that the energy measurement erro s negligible
and that a meter reading at the required level of accuracy is stil possible . When the
example PVM load center 400 i operating in this mode, it can no longer perform step
3 of the checksum function 300, and assumes that all other meters are operating
correctly (i.e., the PVM load center 400 can no longer perform verification). This
mode is intended to be employed for a relatively short duration until the faulty meter
can be identified and replaced.
Example 24
The energy loss ¾ term of Equations 2-4 can correspond to energy
losses (e.g., in, for example and without limitation, line bus bars (not shown) of
the PVM load center 400 between the main PVMCB 402 and the branch PVMCBs
404.
Example 25
The main PVMCB 402 can be placed in a lock-out compartment 420 in
order to prevent tampering. The service disconnect (e.g., operator handle 422 is still
accessible and remotely controllable. The lock-out compartment 420 substantially
encloses the main VMCB 402 and restricts access thereto. The lock-out
compartment 420 includes an opening 4 , and the operating handle 422 passes
through the lock-out compartment opening 42 i , in order to permit access to the
operating handle 422 by a user.
Alternatively, the lock-out compartment 420 ' of Figure 8 includes
openings 4 ,42 1' for the operating handles 422,422 ' of all of the respective PVMCB
circuit breakers 402,404, which are substantially enclosed therein to restrict access to
prevent tampering.
Example 26
A shunt tr p 424 can be added to the main PVMCB 402 with, for
example and without limitation, a button or other suitable user i put device 426 on the
exterior 428 of a building 430 in order to meet fire codes requiring an accessible
whole-home disconnect .
impie 27
Additional information can be communicated n real time to
emergency responders at a remote location, such as 40 (Figure 2), by the main
PVMCB 402 This can include information, such as which ones of the branch
PVMCBs 404 have tripped and in what order. This could assist firefighters to
determine the source and location of a fire in the building 430. Another possibility i
automatic notification of a possible electrocution if a certain power signature i
observed (e.g., without limitation, a ground fault 432 in a bathroom).
Example 2
Also, remote control of individual branch power circuits associated
with the branch PVMCBs 404 could be given to emergency responders at a remote
location, such as 0 (Figure 2).
Example 29
A faulty meter can arise from any number of the components of the
example PVMCB 0 (e.g., without limitation, voltage se sor(s ; the current
sensor(s) 48, 49; analog-to-digttal converter (ADC) (not shown) of power metering
circuit 2; processor 4 and could involve gain and/or offset error(s). However, an
offset error calibration from the factory should not normally drift or change ver
much over time. As a result, expected errors likely involve a change in the gai
calibration.
Although the exact source of the error cannot he determined, it might
be possible to pinpoint it close enough for correction. For example, the voltage
determination is combination of a reading from a voltage sensor 0, and th
ADC. nside load center such as 400, for example, the voltage should be nearly
exactly the same for all of the PVMCBs 404. Hence, a voltage error can readily be
detected and corrected b the analytics. By adjusting a u ber of coefficients used i
its determination (e.g., without limitation a simple multiplication term), then the
voltage can be re-calibrated back to ts correct value. f the re-calibrated voltage
changes or drifts, then this error ay be unrecoverable, although an average of the
various voltages in the load center 400 ca be used as a substitute. f however, the
re-calibrated volta s suhstantiallv constant, although it raav be difficult to
determine what went wrong, the voltage sensor 0 or nevertheless s operational.
Similar calibration ca be used for the current sensor(s) 8, 49.
Since power is derived from current and voltage, and since energy is
derived fro power or from current and voltage, knowing the particular device that
failed and the amount of erroneous energy, these can be used to re-calibrate th
current o voltage sensor(s).
Example 30
The disclosed checksum function 300 improves metering verification
(and thereby a utility s ability to meter customers accurately) b performing repetitive
verification in rea time. When accuracy has been compromised and verification fails
on a system wit ' meter points, the checksum function 300 will determine the
faulty meter, notify the utility, and then recover the system to operate in a failure
mode with -F meters, but without loss of metering capability. Due t the
arrangement of the meters, the checksum function 300 is able to properl and
accurately mete the meter points with N- Ϊ meters until the faulty meter can be
replaced. The checksum function 300 permits a system of self-verifying devices to
remove the burden of meter testin and verification from the electric utility. It also
creates a more reliable and accurate metering system for utilities which prevents the
theft of electric power while ensuring that customers are properly billed.
Example 3
The checksum function 300 cannot guarantee detection of multiple
simultaneous failures. There are certain cases where the checksum function 300 can
detect/suspect simultaneous failures based on its analysis, but there are various other
cases where it cannot. One example would be when o meter reading errs on th
high side and a second meter reading errs of equal magnitude on the low side and the
combination of the two offset each other. As a result, the checksum function 300 may
no be able to detect such errors. However, the occurrence of multiple, simultaneous
errors occurring (having started at the same time), is statistically an outlier.
f the are multiple errors thai offset each other. but t e ' are ot
simultaneous (having started at different times), then the checksum function 300 may
uot be able to discern whether there are multiple errors or f the first error has bee
ixed or was a anoma . Therefore, the checksum function 300 la s this scenario as
an error and notifies the utility and customer appropriately.
The checksum function 300 may not be able to allocate energy to every
power circuit after a simultaneous failure has occurred. Each individual meter point
can still be allocated, but it will be unverified, since the checksum function 300 does
not have enough information to fully properly function.
Example 32
Figure 8 shows an upstream PVMCB 500 including the checksum
function 300 of Figure 5, a transformer 502 and a plurality of loa centers
504,506,508. Each of the load centers 504,506,508 includes a mai PVMCB 1
which s similar to the main PVMCB 402 of Figure 7, except that the main PVMCB
need not include the checksum function 300. Here the checksum function 300 is
employed to check energy flowing through the transformer 502 and through multiple
load centers 504,506,508 possibly located at different premises. This is an additional
place in a distribution system where an electric utility could employ this checksum
function 300 to, for example, annunciate and prevent the theft or loss of power.
Example 33
As was discussed, the disclosed concept does not address, with
certainty, a scenario of a plurality of meter fai res occurring simultaneously, in this
example, the mai PVMCB 510 does include the checksum function 300 for operation
with its downstream branch PVMCBs 404. Using an additional set of devices, such
as shown in Figure 8, to perform multiple checksum functions 300 could help validate
where a "meter" has actually failed. For example, if two branch PVMCBs 404
(Figures 7 and 8} fail simultaneously, then the checksum function 300 of Figure 5
would indicate that the main PVMCB 402 (Figure 7) or the main PVMCB 5 0 of the
load center 508 (Figure 8) failed. However if the checksum function 300 is still
passing between the transformer 502 as executed at the example PVMCB 500 and the
main PVMCBs 5 0 (Figure 8} electrically connected thereto, then the mai PVMCB
0 of the load center 508 (Figure 8) has not failed even though the checksum
function 300 VMCB 0 could say thai it i f the two branch PVMCBs 404
( gure 8} fa simultaneously.
Ex nipi 34
Figure 9 shows a transformer 600 and a plurality of transmission lines
602,604,606 including the checksum function 300 of Figure 5. The transformer 600
includes a plurality of secondary windings 608.610.612 and a primary winding 614
having a first metering circuit 16 including the checksum function 300. Each of the
downstream transmission lines 602,604,606 corresponds to one of the secondar
windings 608,610,612, respectively and includes second metering circuit 6 18. The
metering circuits 616,618 can be part of respective PVMCBs 620,622, as shown. For
equation 4, the I¾w ter can include expected energy losses in the transformer 600.
For utilities branc circuit metering and control wit guaranteed
accuracy allows better service to their territories, increases the amou t of information
used to make decisions, offers new rate structures, provides remote meter reading,
remote senice disconnects and an emergency demand response system, prevents theft
of power, and helps to improve asset utilization.
For consumers, Bs. suc as 0, and add-on modules, such as
6 or 200. assure accurate billing help conserve energy, and increase the value and
usefulness of their load center and the devices supported therein.
While specific embodiments of the disclosed concept have been
described in detail, it wi l be appreciated by those skilled in d e 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
an and al equivalents thereof.

What is claimd is:
!. An electric power distribution system (2) for use with an
electric power source (4), said electric power distribution system comprising:
a first device (6) exchanging first electric power with said
electric power source, said first device being structured to exchange said first electric
power with a plurality of second devices (8) ami to meter first electric energy ( )
corresponding to said first electric power;
said plurality of second devices (8) structured to exchange said
first electric power with said first device, each of said seco d devices being structured
to exchange seco d electric power as at least part of said first electric powe with a
number of corresponding electric loads (12) and to meter second electric energy (14)
corresponding to said second electric power; and
a processor ( ) comprising a routine ( ;3 0) structured to
compare the metered first electric energy f om sa d first device with a sum of the
metered second electric energy from each of said second devices, and to responsiveiy
determine proper or improper operation of said electric power distribution system.
2 . The electric power distribution system (2) of Claim 1 wherein
said routine is further structured (304) to notify an electric utility (20) corresponding
to said electric power source responsive to said determined improper operation, (306)
to determine which one of said first device and said second devices failed responsive
to sai determined improper operation, (302) to determine a predetermined plurality
of consecut e occurrences of sai determined improper operation and responsiveiy
notify (304) at least one of an electric utility (20; . 18) corresponding to said electric
power source and a customer for said second electric power, (302) to determine a
predetermined number of occurrences of said determined improper operation a d
responsiveiy notify (304) at least one of an electric utility (20; 8) corresponding to
said electric power source and a customer for said second electric power, or (306:338)
to determine which one of said first device a d sai second devices fai le responsive
to said determined improper operation by checking for reverse power flow back
toward said electric power source.
3 . The electric power distribution system (2;400) of Claim Ϊ
wherein said first device is a main circuit breaker (402) and said second devices are a
plurality of branch circuit breakers (404), wherein said first device is a transformer
(502) including a first metering circuit (500) and said second devices are a plurality of
downstream load centers or panelboards (504,506,508) each of which includes a
second metering circuii (5 0) sai first device is a first transformer (600) including a
plurality of secondary windings (608, 0 , ) an a primary winding (614) having a
first metering circuit ( ), an said second devices are a plurality of downstream
transmission lines (602,604,606), each of said downstream transmission lines
corresponding to one of said secondary windings and including a second metering
circuit ( 8), or said first device is an upstream power distribution device (6;600)
having a first metering circuit (22;6I6) and said second devices are a plurality of
downstream power distribution devices (8;6 2 6G4 6G6) each of said downstream
power distribution devices including a second metering circuit (24;6i 8).
4 . The electric power distribution system (2) of Claim 1 wherein
said routine is further structured (306) to determine which one of said first device and
said second devices failed responsive to said determined improper operation; and
wherein said routine is further structured to allocate ( 1 ) energy to said one of said
first device and said second devices that failed responsive to said determined
improper operation, or wherein said routine is further structured to allocate ( ) a
plurality of time-stamped energy values fo a predetermined time period to said one of
said first device and said second devices that failed after said determined improper
operation
5. The electric power distribution system (2) of Claim 1 wherein
each of said first device an said second devices includes a metering circuit (152); and
wherein said routine is further structured (301) to adjust said compare for at least one
of energy losses i power conductors operative!y associated with said second devices,
and expected errors in the metering circuii of each of said first device and said second
devices.
6 . The electric power distribution system (2) of Claim 1 wherein
said routine is further structured (302) to determine a predetermined number of
occurrences of said determined improper operation and responsively notify (304) at
least one of an electric utility (20; ) corresponding to said electric power source
and a customer for said second electric power; and wherein said routine is further
s ctured (306) to determine which one of said first device and said second devices
failed by comparing a number of load events with a plurality of predetermined load
signatures, (306) to determine which one of said first device and said second devices
failed by evaluating temperature versus time information and energy versus time
information for number of said second devices, (306) to determine which one of
said first device and said second devices failed by evaluating at least one of: (!)
expected energy versus time information, power source or power sink with actual
energ versus lime information; and (2) load type or rated current with actual current
versus time information, for a number of said second devices, (306 to determine
which one of said first device and said second devices failed by evaluating at least one
of: ( ) installation date; and (2) number of operating cycles, for a plurality of said first
device and said second devices, (306;326,328,330;340344) to determine which one
of said first device and said second devices failed by turning one of said second
devices off and repeating said compare the metered first electric energy from said first
device with a sum of the metered second electric energy fro each of said second
devices except for said one of said second devices and to responsively re-determine
said proper or said improper operation based upon sai repeating said compare, or
(306) to determine whic one of said first device and said second devices failed, and
to responsively determine (306,3 ) a second electric energy for said one of said first
device and sai second devices that failed from the metered first electric ener v from
said first device, less the sum of the metered second electric e ergy from each of said
second devices, less energy losses in power conductors operatively associated with
said second devices, less the metered second electric energy from said one of said first
device and said second devices that failed.
7 The electric powe distribution system (2) of Claim 3 wherein
said main circuit breake (402) and said plurality of branch circuit breakers (404) are
housed in a paneiboard or load center (400); wherein said main circuit breaker
includes an operating handle (422); wherein said paneiboard or load center includes a
lock-out compartment (420) substantially enclosing said main circuit breaker and
restricting access thereto, said lock-out compartment including an opening (42 ), the
operating handle passing through the opening of said lock-out compartment, in order
to permit access to the operating handle by a user.
8 the eiectric power distribution system ( ) of Clai 3 wherein
said main circuit breaker (402) a d said plurality of bra ch circuit breakers (404) are
housed in anelboard or load center (400) inside of a buddi g (430); and wherein
shunt tr p user interface (426) is disposed outside of said building a d interfaced to
said main circuit breaker in order to manually trip open said main circuit breaker
fro outside of said building.
9 The electric power distribution system (2) of Claim 3 wherein
said main circuit breaker (402) comprises communication circuit ( 4, 6)
structured to receive information om said branch circuit breakers and communicate
said information to a remote location ( 0); and wherein said information is selected
from the group consisting of an identification of trip status and time of trip for each of
said branc circuit breakers, and an identification of trip status and occurrence of a
predetermined power signature for each of said branch circuit breakers.
10 The electric power distribution system (2) of Claim 3 wherein
said main circuit breaker (402) comprises a communication circuit (134,136)
structured to receive an open or close command from a remote location ( 0) and
communicaie said open or close command to a corresponding one of said branch
circuit breakers.
11 The electric power distribution system ( ) of Claim 3 wherein
said main circuit breaker (402) and said plurality of branch circuit breakers (404) are
housed in a panelboard or load center (400); wherein each of said main circuit breaker
an said branch circuit breakers includes an operating handle (422); wherein said
panelboard or load center includes a lock-out compartment. (420 ') substantially
enclosing said main circuit breaker and said branch circuit breakers and restricting
access thereto; and wherein said lock-out compartment includes a plurality of
openings (42 ' ), the operating handle of a corresponding one of said main circuit
breaker and said branch circuit breakers passing through a corresponding one of the
openings of said lock-out compartment, in order to permit access to th operati ng
handle by a user.
12. The eiectric power distribution system (2) of Claim 1 wherein
at least one (408,410) of said number of corresponding electric loads is structured to
generate eiectric power; wherein a corresponding one of said second devices is further
structured to send said generated electric power back to said first device; and whereto
said metered second electric energy of said corresponding one of said second devices
has a negative value.
13 . The electric power distribution system (2) of Claim 12 wherein
said first device is further structured to send electric power back to said electric power
source; a wherein said metered first electric energy has a negative value.
14. A method of evaluating energy metering of an electric power
distribution system (2 for use with an electric power source (4), the electric power
distribution system comprising a first device (6) exchanging first electric power with
said electric power source said first device exchanging the .first electric power with a
p lurality of second devices (8) and metering first electric energy corresponding to said
first electric power, sai plurality of second devices exchanging the first electric
power with said first device, each of said second devices exchanging second electric
power as at least part of said first electric power with a number of corresponding
electric loads (12) and metering second electric energy corresponding to said second
electric power said method comprising:
summing (301) the metered second electric energ from each
of said second devices; and
comparing (3 ) with a processor ( 4) the metered first
electric energy from said first device with the summed metered second electric energy
from each of sai second devices, and responsively determining proper or improper
operation of said metering first electric energy and said metering second electric
energy
15 The method of Claim mrther comprising;
determining (302) said improper operation when the metered
first electric energy from said first device less the summed metered second electricenergy
from each of sai second devices is greater tha a sum of losses in power
conductors operatively associated with said second devices, plus expected errors in
metering by each of said first device and said second devices.