A Home Appliance Recognition System Using the Approach of Measuring Power Consumption and Power Factor on the Electrical Panel, Based on Energy Meter ICs

doi:10.4236/cs.2013.43033

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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

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 ap-

pliance 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 appli-

ance recognition is the foundation to promote energy

efficiency, since it generates benefits both to the custom-

ers, who can manage the use of their appliances and ob-

tain 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 meas-

ure 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 intelli-

gent device monitors the power consumption of all ap-

pliances and then processes the monitored signal to iden-

tify 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.

Load Signature is an electrical expression that an ap-

pliance distinctly possesses regarding its electrical be-

haviour. It can be acquired from power consumption lev-

els or from waveforms of electrical quantities such as

voltage and current. Almost every electrical measure-

ment can be treated as a load signature. It can be repre-

sented 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 appli-

ances 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.

*This work was partially supported by CAPES. In this paper we propose the use of a similar approach

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-per-

formance 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 com-

puters and mobile devices with wireless internet capabil-

ity, such as tablets and smartphones.

Figure 1. Block diagram of the proposed system.

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 volt-

age. The current of each electric circuit Ci that comes

from circuit breakers Di, pass through a current trans-

former 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, po-

tential 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 trans-

formers. 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

J. Z. MORO ET AL.

247

Y7 2

Y6 3

Y5 4

Y4 5

Y3 6

Y2 7

Y1 8

Y0 9

GND

13 S2

Y15 16

Y14 17

Y13 18

Y12 19

Y11 20

Y10 21

Y9 22

Y8 23

VCC

PC6 (RESET)1

PD0 (RXD)

PD1 (TXD)

PD2 (INT0)

PD3 (INT1)

PD4 (XCK/T0)

VCC 7

GND 8

PB6 (XTAL1/TOSC1)

PB7 (XTAL2/TOSC2)

PD5 (T1)

PD6 (AIN0)

PD7 (AIN1)

PB0 (ICP)

PB1 (OC1A)

PB2 (SS/OC1B)

PB3 (MOSI/OC2)

PB4 (MISO)

PB5 (SCK)

AVCC 20

AREF 21

GND 22

PC0 (ADC0)23

PC1 (ADC1)24

PC2 (ADC2)25

PC3 (ADC3)26

PC4 (ADC4/SDA)27

PC5 (ADC5/SCL)28

ATmega8-16PI

910

1112

1314

1516

1718

Header 9X2

DVCC

DGND

910

1112

1314

1516

1718

Header 9X2

Y7 2

Y6 3

Y5 4

Y4 5

Y3 6

Y2 7

Y1 8

Y0 9

GND

13 S2

Y15 16

Y14 17

Y13 18

Y12 19

Y11 20

Y10 21

Y9 22

Y8 23

VCC

CH1

DVCC

DGND

100n

47k

22p

16MHz

DGND

DVCC

LED1

AGND

DGND

DVCC

WiFi_CS

MOSI

MISO

SCLK

MOSI

MISO

SCLK

DVCC

AGND

MOSI

MISO

SCLK

1 2

3 4

5 6

ICSP

DVCC

DGND

MOSI

MISO

SCLK

RST

R11R12R13R14R15R16R17R9R10

R26R27R28R29R30R31R32R33R34 DGND

DVCC

Header 3

DGND

INT0

Flash_CS

CH2

SW-PB MJTP1230

DGND

LED_CV

R40

R41

Figure 3. Schematic of the main board circuit including the µC and the switching connections.

Diode 1N4148

DVCC

3V3

DGND

Trafo 2 saídas

AGNDNEUTRO

FASE A

FASE B

FASE C

2700u

C7 100u

100n 10u

C10

Trafo 2 saídas

OUT 4

GND

OUT 2

SPX1117M3-L-5-0

GND 1

VOUT 2

VIN

MCP1700T-33 02E/TT

Diode 1N4148

Header 3DGND

Header 2

R42

Res Varistor

GND

VDD_1.8

JTAG_TDO

JTAG_TCK

JTAG_TMS

JTAG_TDI

RST_N

DNC

JTAG_RST_N

GND

VDD_1.8

DNC

RES

VDD_3.3

GND

18 GND 19

CE_N 20

JTAG_EN 21

DNC 22

SCS_N 23

VDD_1.8 24

GND 25

UART_RX 26

UART_TX 27

GND 28

VDD_3.3 29

GND 30

VDD_1.8 31

SDO 32

INT_NX 33

SCK 34

SDI 35

GND 36

ZG2100MG

SCK

RESET

4WP 5

VCC 6

GND 7

SO 8

AT45DB161D-S U

DGND DGND

3V33V3

100n C1

100n

4k7

MOSI

SCLK

INT0

MISO

WiFi_ CS

RST

DVCC

MOSI

SCLK

RST

Flash_CS

MISO

DGND

3V3

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 no-

ticed. Since the board receives 3 phases and the neutral,

he voltage of the corresponding phase is selected with t

J. Z. MORO ET AL.

248

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 no-

tation follows the following rule: VXY = Vxn − Vyn. Us-

ing jumpers it is possible to select any voltage signals to

each energy power meter, properly setting up the system

according to the circuit each meter is connected to. Fig-

ure 9 shows two examples illustrating this situation.

Figure 10 the phase selector jumpers.

4. Software

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 microcon-

troller 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. Oth-

erwise 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

RESET

DVDD

AVDD

V1P

V1N

V2N

V2P

AGND

REF

DGND

10 CF 11

ZX 12

SAG 13

IRQ 14

CLKIN 15

CLKOUT 16

CS 17

SCLK 18

MISO 19

MOSI 20

ADE7763

DGND

DVCCAVCC

AGND

1 2

XTAL

DGND

AVCCDVCC

AGNDDGND

18p

C17

100n

C20

100n

10u

C19

10u

C18

10u

100n

Ferrite Bead

AGND

MOSI

MISO

SCLK

CS1

AGND

AGND DGND

DVCC

CS3

CS2

CS1

CS4

1 2

3 4

5 6

1 2

3 4

5 6

7 8

RESET

DVDD

AVDD

V1P

V1N

V2N

V2P

AGND

REF

DGND

10 CF 11

ZX 12

SAG 13

IRQ 14

CLKIN 15

CLKOUT 16

CS 17

SCLK 18

MISO 19

MOSI 20

ADE7763

DGND

DVCCAVCC

AGND

1 2

XTAL

DGND

C10

18p

C16

10u

C15

100n

AGND

MOSI

MISO

SCLK

CS2

AGND

1 2

3 4

5 6

1 2

3 4

5 6

7 8

1IP 2

Current _Trafo

1IP 2

Current _Trafo

CS6

CS5

CS7CS9

MISO

CS8

MOSI

SCLK

1 2

3 4

5 6

7 8

910

11 12

13 14

15 16

17 18

Header 9X2

1kR1

1kR2

1kR3

1kR4

22k

R9 1k

R10

1kR11

1kR12

R13

R14

22k

R15

22k

R16

33n

C11

33n

C12

33n

C13

33n

C14

33n

Figure 6. Schematic of the measuring board circuit.

J. Z. MORO ET AL. 249

Figure 7. Measuring board.

Figure 8. Measuring board installed inside of the circuit

breakers box.

Figure 9. Example of phase voltage and line voltage, se-

lected 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.

Figure 10. Detail of the measuring board, showing the se-

lectors jumpers.

Figure 11. Flowchart of the embedded firmware.

5. System Setup and Operation

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 note-

book 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 ac-

tive 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 ex-

ample, 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

J. Z. MORO ET AL.

250

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 bed-

room incandescent lamps) the system has to be updated

by deleting the old information about the replaced de-

vices 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 micro-

controller 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 be-

tween 3 lamps instead of 30.

This technique reduces significantly the number of ap-

pliances 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 pow-

erful than the other techniques currently available.

6. Experimental Results

The system was tested and the loads were chosen to in-

tentionally 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 incandes-

cent 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 iden-

tify precisely which 20 W lamp was on, because of the

P.F.

A second test was made turning on/off the 40 W in-

candescent 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 cir-

cuit” 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 appli-

ances 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 identifica-

tion becomes easier, so the program used to do that iden-

tification can be executed by a simple 8 bits microcon-

troller, which parallel executes others tasks such as those

requested by TCP/IP stack.

REFERENCES

[1] L. F. C. Duarte, E. C. Ferreira and J. A. S. Dias, “Energy

Measurement Techniques for Energy Efficiency Programs,”

In: Moustafa Eissa, Ed., Energy Efficiency—The Innova-

tive Ways for Smart Energy, the Future Towards Modern

Utilities, InTech, 2012, pp. 193-208. doi:10.5772/47791

[2] H. Serra, J. Correia, A. J. Gano, A. M. de Campos and I.

Teixeira, “Domestic Power Consumption Measurement and

Automatic Home Appliance Detection,” Proceedings of

J. Z. MORO ET AL.

251

2005 IEEE International Workshop Intelligent Signal Pro c-

essing, 1-3 September 2005, pp. 128-132.

[3] L. F. C. Duarte, J. D. Zambianco, D. Airoldi, E. C.

Ferreira and J. A. S. Dias, “Characterization and Break-

down of the Electricity Bill Using Custom Smart Meters:

A Tool for Energy-Efficiency Programs,” International

Journal of Circuits, Systems and Signal Processing, Vol.

5, No. 2, 2011, pp. 116-123.

[4] C. Laughman, K. Lee, R. Cox, S. Shaw, S. Leeb, L. Nor-

ford and P. Armstrong, “Power Signature Analysis,” IEEE

Power and Energy Magazine, Vol. 1, No. 2, 2003, pp. 56-

63. doi:10.1109/MPAE.2003.1192027

[5] J. Duan, D. Czarkowski and Z. Zabar, “Neural Network

Approach for Estimation of Load Composition,” IEEE

International Symposium on Circuit and Systems (ISCAS),

New York, 23-26 May 2004, pp. 988-991.

[6] W. K. Lee, G. S. K. Fung, H. Y. Lam and F. H. Y. Chan,

“Exploration on Load Signatures,” Proceedings of Inter-

national Conference on Electrical Engineering (ICEE),

2004.

http://lucente.us/db/pubs/ICEE2004Signature-reprint.pdf

[7] J. S. K. Leung, K. S. H. Ng and J. W. M. Cheng, “Identi-

fying Appliances Using Load Signatures and Genetic

Algorithms,” Proceedings of International Conference on

Electrical Engineering (ICEE), 2007.

http://www.icee-con.org/papers/2007/Oral_Poster%20Pa

pers/01/ICEE-031.pdf

[8] G. Lin, S. Lee, J. Y. Hsu and W. Jih, “Applying Power

Meters for Appliance Recognition on the Electric Panel,”

Proceedings of the 5th IEEE Conference on Industrial

Electronics and Applications (ICIEA), Taichung, 15-17

June 2010, pp. 2254-2259.

[9] Analog Devices, “ADE7763 Data Sheet,” Single-Phase

Active and Apparent Energy Metering IC, 2009.