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Circuits and Systems, 2013, 4, 245-251
http://dx.doi.org/10.4236/cs.2013.43033 Published Online July 2013 (http://www.scirp.org/journal/cs)
A Home Appliance Recognition System Using the
Approach of Measuring Power Consumption and Power
Factor on the Electrical Panel, Based on Energy Meter ICs*
Jefferson Z. Moro, Luís F. C. Duarte, Elnatan C. Ferreira, José A. Siqueira Dias
Department of Electronic and Microelectronic, State University of Campinas, Campinas, Brazil
Email: [email protected], [email protected],
[email protected], [email protected]
Received February 16, 2013; revised March 17, 2013; accepted March 25, 2013
Copyright © 2013 Jefferson Z. Moro et al. This is an open access article distributed under the Creative Commons Attribution License,
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
ABSTRACT
Currently a large effort is being done with the intention to educate people about how much energy each electrical appliance uses in their houses, since this knowledge is the fundamental basis of energy efficiency programs that can be
managed by the household owners. This paper presents a simple yet functional non-intrusive method for electric power
measurement that can be applied in energy efficiency programs, in order to provide a better knowledge of the energy
consumption of the appliances in a home.
Keywords: Energy Consumption; Energy Efficiency; Energy Metering; Power Measurement
1. Introduction
An accurate knowledge of the electric loads and appliance recognition is the foundation to promote energy
efficiency, since it generates benefits both to the customers, who can manage the use of their appliances and obtain reduced costs in their electrical bills, and also for the
utilities, which can optimize the operation and planning
of the system [1].
Many techniques and methods have been used to measure the appliances power consumption and monitor their
states. One approach to acquire the appliances power
consumption and their states is to make use of a wireless
sensor network. In this case, every appliance in a house
must be connected to a smart sensor that performs the
power measurement. The information of all the smart
meters is then concatenated and is sent to system that
generates a report [2,3].
Another approach is to make use of a single intelligent
power meter installed in the electric panel. This intelligent device monitors the power consumption of all appliances and then processes the monitored signal to identify the appliances based on load signatures. It minimizes
the number of sensors needed to monitor all appliances
and also reduces the complexity of the installation.
*
This work was partially supported by CAPES.
Copyright © 2013 SciRes.
Load Signature is an electrical expression that an appliance distinctly possesses regarding its electrical behaviour. It can be acquired from power consumption levels or from waveforms of electrical quantities such as
voltage and current. Almost every electrical measurement can be treated as a load signature. It can be represented in the time domain [4], in the frequency domain [5]
and can also be represented mathematically in terms of
wavelets, eigenvalues, or components of the Singular
Value Decomposition (SVD) [6].
In [7] the authors proposed a methodology of using
load signatures and Genetic Algorithms (GA) to identify
electrical appliances from a composite load signal. They
introduced a classification method to group the appliances and how to disaggregate the composite load signals
by a GA identification process which is generated from a
random combination of load signatures from the distinct
groups of appliances.
Recently a proposal for appliance recognition by
measuring the power consumption of each circuit at the
electrical panel distribution board has been presented [8].
The technique uses a sophisticated meter and based on
the instantaneous measurements results of the energy
meter and on expected behaviour of the residents of the
house provides good results for the appliance recognition
process.
In this paper we propose the use of a similar approach
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J. Z. MORO ET AL.
246
of measuring the electrical circuits at circuit level, with
one power meter for each circuit breaker, but using a low
cost hardware. The proposed hardware is composed of
simple energy meter integrated circuits and a recognition
algorithm which does not rely on an expected behaviour
of the residents, since this can change drastically form
culture to culture.
2. Objective
The goal of this work is the development of a system
able to measure and separate the power consumption of
different appliances in a house, in order to provide better
knowledge of the energy consumption of the appliances
in a residence.
3. Hardware
The developed hardware has four modules: a PCB with
the energy meter IC, a microcontroller that is responsible
for the management of all modules, a memory for data
storage and a Wi-Fi module which transmits the data to
any device with Wi-Fi connection. A block diagram of
the system is shown in Figure 1.
The power meter is basically composed of a modular
printed circuit board with small current transformers, one
for each circuit breaker at the distribution panel. The
voltage at circuit is also fed to modular board, so that
each energy meter integrated circuit (one per module)
receives both the current (via current transformer) and
the voltage at that circuit. The energy meter IC is the
ADE7763 [9]. This IC was chosen because it has the
capability of measuring both active and apparent energy,
and it communicates to others ICs using SPI. Thus, only
a few wires are required to interconnect all the modular
energy meter boards with the microcontroller.
The microcontroller is an ATmega328. A high-performance Atmel 8-bit AVR RISC-based microcontroller
with 32 kB of flash memory, 2 kB of RAM and 1 kB of
EEPROM. It is an inexpensive and easy to programs IC
with many open source codes and libraries available.
The Wi-Fi network was chosen in order to allow the
energy information data to be accessed both from computers and mobile devices with wireless internet capability, such as tablets and smartphones.
Figure 1. Block diagram of the proposed system.
Copyright © 2013 SciRes.
Figure 2. Diagram of installation showing the measurement
performed in each circuit apart.
On Figure 2, T represents a group of three potential
transformers supplied by each one of the three phases of
the mains line. These transformers reduce the voltage and
also isolate the grid allowing the ICs to sample the voltage. The current of each electric circuit Ci that comes
from circuit breakers Di, pass through a current transformer and is then acquired by the a dedicated power
meter IC Mi.
The prototype was mounted on the form of two boards:
one main board and one measuring board. The main
board is composed by the memory, the Wi-Fi module,
the processing unit (microcontroller), power supply, potential transformers and auxiliary circuits. Figures 3 and
4 show the schematic of the main board circuit and a
photograph of the assembled main board is shown in
Figure 5.
The measuring board is basically composed by the
measuring electronics circuits and by the currents transformers. It was designed and fabricated according to the
schematic diagram presented in Figure 6.
Each measuring board was fabricated with nine IC
power meters. The position of the current transformer
was set-up to be perfectly aligned with the wire input of
the circuit breaker, so that the installation of the board is
extremely simple. The complete measuring board with
the current transformers soldered on it is presented in
Figure 7.
The final assembling of the measurement board in an
electrical panel is presented in Figure 8. As it can be
CS
J. Z. MORO ET AL.
247
DVCC
R9R10
R11
R12
R13
R14
R15
R16
R17
10
11
14
13
DVCC
P4
MISO
SCLK
RST
1
3
5
2
4
6
MOSI
ICSP
S0
S1
S2
S3
DVCC
24
12
DGND
VCC
GND
DGND
15
CH2
1k
D1
2
LED1
1
C5
22p
C6
22p
DGND
P5
3
2
1
PB0 (ICP)
PB1 (OC1A)
PB2 (SS/OC1B)
PB3 (MOSI/OC2)
PB4 (MISO)
PB5 (SCK)
PB6 (XTAL1/TOSC1)
PB7 (XTAL2/TOSC2)
PD0 (RXD)
PD1 (TXD)
PD2 (INT0)
PD3 (INT1)
PD4 (XCK/T0)
PD5 (T1)
PD6 (AIN0)
PD7 (AIN1)
Header 3
DGND
1k
PC0 (ADC0)
PC1 (ADC1)
PC2 (ADC2)
PC3 (ADC3)
PC4 (ADC4/SDA)
PC5 (ADC5/SCL)
PC6 (RESET)
VCC
AVCC
AREF
GND
GND
Z
1
2
14
15
SW-PB MJTP1230
WiFi_CS16
MOSI 17
MISO 18
SCLK 19
9
X1
10
16MHz
2
3
INT0
4
5
6
11
R40 R41
12
Flash_CS13
23
24
25
26
27
28
1
9
8
7
6
5
4
3
2
23
22
21
20
19
18
17
16
P1
18
16
14
12
10
8
6
4
2
FC
FB
FA
17
15
13
11
9
7
5
3
1
MOSI
MISO
SCLK
DVCC
Header 9X2
AGND
DGND
1
R7
E
U1
3
4
Y0
Y1
Y2
Y3
Y4
Y5
Y6
Y7
Y8
Y9
Y10
Y11
Y12
Y13
Y14
Y15
U5
RST
DVCC
3
4
R8
47k
7
20
C4
C3
21
100n 100n
22
8
CH1
1
2
10
11
14
13
S0
S1
S2
S3
DVCC
24
12
DGND
1k
ATmega8-16PI
D2
D3
LED_CV LED_CV
VCC
GND
DGND
15
Z
E
9
8
7
6
5
4
3
2
23
22
21
20
19
18
17
16
P2
18
16
14
12
10
8
6
4
2
FC
FB
FA
17
15
13
11
9
7
5
3
1
MOSI
MISO
SCLK
DVCC
Header 9X2
AGND
R26
R27
R28
R29
R30
R31
R32
R33
R34
1
DGND
Y0
Y1
Y2
Y3
Y4
Y5
Y6
Y7
Y8
Y9
Y10
Y11
Y12
Y13
Y14
Y15
DGND
DVCC
U6
Figure 3. Schematic of the main board circuit including the µC and the switching connections.
D6
D4
Diode 1N4148
Diode 1N4148
D7
D5
3V3
DVCC
P6
1
2
3
3
R42
C7
Res Varistor
2700u
DGND
Diode 1N4148
Diode 1N4148
IN
C8
100n
U8
OUT
OUT
GND
2
4
1
Header 3
U7
C9
100u
3
VIN VOUT
GND
2
C10
10u
1
MCP1700T-3302E/TT
SPX1117M3-L-5-0
DGND
T1
7
FASE A1
3V3
3V3
R3 R4
4k7 4k7
FA
U2
6
2
1
5
3
2
4
3
Trafo 2 saídas
R1
P7
T2
2
1
7
FASE B 1
RST
4
7
8
Trafo 2 saídas
Header 2
5
6
5
3
2
1
4k7
6
2
Header 2
P8
FB
4
9
T3
7
FASE C1
FC
10
6
2
11
5
3
12
4
13
Trafo 2 saídas
NEUTRO
14
AGND
15
16
DVCC
R6
4k7
3V3
17
U3
MOSI
SCLK
RST
Flash_CS
1
2
3
4
SI
SO
SCK
GND
RESET VCC
CS
WP
8
7
6
5
MISO
DGND
100n C1
R5
4k7
18
GND
VDD_1.8
ZG2100MG
GND
SDI
JTAG_TDO
SCK
JTAG_TCK
INT_NX
JTAG_TMS
SDO
JTAG_TDI
RST_N
DNC
JTAG_RST_N
VDD_1.8
GND
VDD_3.3
GND
GND
UART_TX
VDD_1.8
UART_RX
DNC
GND
DNC
VDD_1.8
DNC
SCS_N
DNC
DNC
RES
JTAG_EN
VDD_3.3
GND
CE_N
GND
36
35
MOSI
34
SCLK
33
INT0
32
MISO
31
30
29
28
27
26
25
24
23
WiFi_CS
C2
100n
22
21
20
19
R2
4k7
ZG2100MG
AT45DB161D-SU
DGND
DGND
Figure 4. Schematic of the main board circuit including the Wi-Fi module and the power sources.
observed, the board is on the background at the panel and,
except for the current transformer, it can hardly be noCopyright © 2013 SciRes.
ticed. Since the board receives 3 phases and the neutral,
the voltage of the corresponding phase is selected with
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J. Z. MORO ET AL.
248
according to the circuit each meter is connected to. Figure 9 shows two examples illustrating this situation.
Figure 10 the phase selector jumpers.
4. Software
Figure 5. Main board.
configuration jumpers existent in each input of every
measuring circuit.
Each one of the electric circuits can be referred to six
voltage values: three possible phase voltages Van, Vbn
and Vcn that are respectively the three voltage of the
three phases A, B and C, referenced to neutral, and three
line voltage VAB, VBC and VCA, that are the voltage of
the three phases referenced between each other. The notation follows the following rule: VXY = Vxn − Vyn. Using jumpers it is possible to select any voltage signals to
each energy power meter, properly setting up the system
R5
AVCC DVCC
5R
2
U1
IP
T1
Current _Trafo
C18
10u
C19
10u
C20
100n
IN
C17
100n
R1
R2
R3
R4
1k
1k
1k
1k
L1
1
C3
R6
Ferrite Bead
DGND
R7
22k
5R
AGND
1
2
3
4
5
6
7
8
9
10
C4
C5
C6
33n 33n 33n 33n
R8
22k
C7
100n
C8
10u
RESET MOSI
DVDD MISO
AVDD SCLK
V1P
CS
V1N CLKOUT
V2N
CLKIN
V2P
IRQ
AGND
SAG
REF
ZX
DGND
CF
20
19
18
17
16
15
14
13
12
11
MOSI
MISO
SCLK
CS1
C1
2
AVCC
1
DVCC
The firmware installed in the microcontroller program
memory is detailed in the flowchart in Figure 11. The
main task executed on the initialization sets up the power
meters ICs, performing an individual circuit calibration.
After that, the firmware verifies if the user wants to make
actualizations on memory data. If yes, the program is
switched to memory loading routine.
The power meter ICs store the measured data. Once
per minute, the microcontroller reads the data of each
circuit via Serial Peripheral Interface (SPI) and then
writes the data in the external flash memory.
The data in the external flash memory is available to
the user via an embedded web server that is accessed via
Wi-Fi. After reading the power meters, the microcontroller verifies if there is any request from the Wi-Fi
module to access the web page. If so, the request is
treated by the TCP/IP stack, and the cycle restarts. Otherwise the cycle is restarted immediately.
The load recognition software was developed using
JavaScript. It was stored in the external flash memory.
From the moment that the web page is requested by the
user, the JavaScript code is sent to client browser and
18p
X1
XTAL
C2
18p
ADE7763
AGND
AGND
DGND
1
3
5
7
CS8
2
4
6
Fa
Fb
Fc
AGND
R13
CS6
U2
T2
Current _Trafo
IP
CS4
IN
P5
1
3
5
7
9
11
13
15
17
2
4
6
8
10
12
14
16
18
AVCC DVCC
5R
CS5
Fa
CS3
1
2
3
4
5
6
7
8
9
10
1k
1k
1k
1k
C11 C12 C13 C14
R14
CS2
CS1
R9
R10
R11
R12
1
Header 9X2
AGND DGND
DVCC
1
3
5
R15
22k
5R
33n 33n 33n 33n
R16
22k
C15
100n
C16
10u
RESET MOSI
DVDD MISO
AVDD SCLK
V1P
CS
V1N CLKOUT
V2N
CLKIN
V2P
IRQ
AGND
SAG
REF
ZX
DGND
CF
20
19
18
17
16
15
14
13
12
11
MOSI
MISO
SCLK
CS2
C9
2
Fb
CS7
Fa
Fb
Fc
1
Fc
2
4
6
8
DGND
2
CS9
AGND
P1
P2
18p
X2
XTAL
C10
18p
ADE7763
AGND
AGND
DGND
MOSI
SCLK
MISO
1
3
5
7
AGND
P3
P4
2
4
6
8
Fa
Fb
Fc
1
3
5
2
4
6
DGND
Fa
Fb
Fc
AGND
Figure 6. Schematic of the measuring board circuit.
Copyright © 2013 SciRes.
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J. Z. MORO ET AL.
249
Figure 7. Measuring board.
Figure 10. Detail of the measuring board, showing the selectors jumpers.
Figure 11. Flowchart of the embedded firmware.
5. System Setup and Operation
Figure 8. Measuring board installed inside of the circuit
breakers box.
Figure 9. Example of phase voltage and line voltage, selected by jumpers.
there, it is executed by client computer. This is a way to
reduce the work of the microcontroller. Figure 12 shows
the flowchart of the program that is sent to browser of the
user through the Wi-Fi module.
Copyright © 2013 SciRes.
After being installed, the system is initiated in learning
mode, with all the electrical appliances of a given circuit
turned off. Next, each appliance is turned on and its
name and location can be entered with the use of a notebook or any other device with internet connection.
The active and reactive energy are measured during a
small period of time (typically 15 s) and the value of active energy and the power factor of that is sent to the PC.
Since the measurement is made during a known period of
time, the PC calculates the active power and the power
factor of the appliance and stores it in a table, associating
this data with the location and the type of load. For example, the table will store the data: Dining room, ceiling
lamp, 100 watts, P.F. 0.98.
In the sequence this load is turned off and one by one
all the other appliances which are connected to the same
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J. Z. MORO ET AL.
erful than the other techniques currently available.
6. Experimental Results
Figure 12. Flowchart of the program executed by the browser.
circuit breaker are turned on, identified and stored by the
software.
The same procedure is made for every circuit until the
whole house is completely identified. If an appliance is
used in more than one place, and these locations are not
protected by the same circuit breaker, the load can be
registered in both locations without problems. As for
example, if a coffee machine is used in the kitchen and in
the dining room.
If an appliance is substituted (for example, the bedroom incandescent lamps) the system has to be updated
by deleting the old information about the replaced devices and acquiring the new one.
Once every appliance signature is recorded, the system
starts to operate, measuring each circuit separately. Then,
in reduced universe, steps in power consumption are
monitored. Not only the active power steps are monitored,
but also the apparent power steps. It allows the microcontroller to calculate the power factor and then use it
together with the active power step as a load signature.
For example, if in a given house there are 30 lamps of
15 watts distributed in 10 rooms (10 different circuits)
the identification software will have to “guess” only between 3 lamps instead of 30.
This technique reduces significantly the number of appliances that have to be identified, making the correct
identification much easier.
Furthermore, the use of simple energy meter ICs that
can measure both active and reactive power leads to an
identification of load appliances that is much more powCopyright © 2013 SciRes.
The system was tested and the loads were chosen to intentionally create difficulty to the proper identification of
appliances in the systems that do not measure reactive
energy.
A test set-up was prepared with one 40 W incandescent lamp, one 20 W compact fluorescent lamp and one
20 W incandescent lamp. The system was capable of
identifying when the 40 W lamp was on by the energy
consumption (measuring during 1 s) and also could identify precisely which 20 W lamp was on, because of the
P.F.
A second test was made turning on/off the 40 W incandescent lamp and the two 20 W lamps simultaneously,
in order to simulate a 40 W appliance. The software can
detect that a step of 40 W was measured with a P.F.
which is not in the table. So, it combines all possible
loads that result in a power step of 40 W and calculates
the P.F. to determine which combination matches the
measured value.
Using this technique it was possible to detect properly
all combinations of these 3 appliances.
7. Conclusions
This paper has presented a novel technique of “per circuit” electrical power metering system able to identify
loads.
The “per circuit” measurement technique significantly
reduces the computational cost of the project, while it
increases the chance of recognizing the loads correctly.
It also facilitates the insertion of a new load in the
system by allowing the user to switch off only the appliances in the same circuit and not all appliances in the
house during the learning event.
Investing in a hardware a little more elaborated, allied
to a good distribution of the currents transducers in the
circuit breakers box, have shown that the load identification becomes easier, so the program used to do that identification can be executed by a simple 8 bits microcontroller, which parallel executes others tasks such as those
requested by TCP/IP stack.
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