Data transmission through power line

International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN 0976 –
6464(Print), ISSN 0976 – 6472(Online), Volume 6, Issue 2, February (2015), pp. 25-34© IAEME
25
DATA TRANSMISSION THROUGH POWER LINE
Nagaraj Shet
Electronics and Communication Department, SDMIT, Ujire, Belthagudi, Karnataka
Shreesha C
Instrumentation and Control Engineering, Manipal Institute of Technology
Udupi, Karnataka
ABSTRACT
In this paper an attempt is made to transmit data over [1] power line. Now a days power line
is getting wide acceptance for sending control signals and communication signals. It has the
advantage of less intial expenses to establish a communication network. In this work it is
demonstrated power line can be used for transmitting data using simple power line communication
interface. The results are promising that power line can also be used for high speed data transfer.
Note to practitioners- Wireless communication has become very popular for data
transmission. Wireless devices are operated by using storage cell or utility power. Many Home
automation products in market are device dependent. With wireless devices huge investment is
required to automate the complete home which is just function specific. These days security is a
serious issue. One can integrate all the functionalities to have affordable commercial product if data
transmission at high rate can be done on power line.
The outcome of this work can become a part of such product which can be plugged in to all
devices which are connected to power line. Such method provides affordable and integrated solution.
If high speed data transmission is possible over power line a microcontroller is the only device that
can be programmed according to applications to make a product.
Index Terms: Power Line Communication, Power Line Data Transmission.
INTRODUCTION
The power line modem uses the power line cable as communication medium. It is convenient
as it eliminates the need to lay additional cables. However the traditionally used channels have come
INTERNATIONAL JOURNAL OF ELECTRONICS AND
COMMUNICATION ENGINEERING & TECHNOLOGY (IJECET)
ISSN 0976 – 6464(Print)
ISSN 0976 – 6472(Online)
Volume 6, Issue 2, February (2015), pp. 25-34
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to a saturation level. There is need to explore new kind of technology which is simpler to implement
and is not as expensive as other related technologies. This can be implemented in small areas such as
residences, offices, etc. Various kind of devices can be controlled remotely. The main benefit of this
system is simplicity of automation of their house. Another major factor is the ubiquity of the medium
- power outlets are commonly found and available throughout the house or the office and may very
well serve as communication nodes.
The external electrical grid can also be used for many applications whose solutions provide
many opportunities for equipment vendors and utilities to offer new services, features and products,
cut costs of current services, fully automate manual processes and procedures. It can also be used to
improve current products, monitor and collect valuable data, offer remote service options and create
new business and revenue streams utilizing the existing infrastructure [2]. Data rates over a power
line communication system vary widely. Low-frequency(about 100- 200 kHz)carriers impressed on
high-voltage transmission lines may carry one or two analog voice circuits, or telemetry and control
circuits with an equivalent data rate of a few hundred bits per second. High speed data
communication is possible using [3] OFDM techniques.
I. BACK GROUND
As technology advances and more technologies are developed and used by society, our
demand for electricity will increase at unpredictable rates. In fact, on a daily basis power companies
are faced with the challenge of distributing power through their power grids without disrupting the
flow of electricity to other users. However, when there is a sudden increase in the demand for
power in a part of the power grid then there can be disastrous effects. When the load is too great for
a power grid there can be outages that can cost the economy millions of dollars and this is simply
unacceptable. Many times it is not by fault of the power company that these outages occur, but
mainly due to mechanical failures at certain nodes or unexpected increases in power consumption at
particular nodes. Power-on-Demand [4] cannot decrease the occurrence of outages due to
mechanical failures, but it can decrease the chances of outages occurring due to unexpected increases
in demand for power. Power-on-Demand is gaining support because of the functionality it purports.
Using this technology, power companies can communicate with their large industrial clients
on an ongoing basis and be assured that their power demands will be met. This will decrease the
probability of an outage being caused by those clients and increase the efficiency of the power
network. The motivation is simple – create efficient power networks by communication. If
companies are successful in implementing Power-on-Demand systems, then this technology can be
further developed to offer other services using Power Line Data Transmission.
Power line communication has been around for quite some time, but has only been used for
narrow band tele-remote relay applications, public lighting and home automation. Broadband over
PLC only began at the end of the 1990s. Although its use is expanding into the distribution area [5]
for load control and even into households for control of lighting, alarming and a/c and heating, the
major application is on Transmission Lines in Protective relaying. A channel is used in line relaying
so that both ends of a circuit are cleared at high speed for all faults, including end zone faults. A PLC
channel can also be used to provide remote tripping functions [6] for transformer protection, shunt
reactor protection and remote breaker failure relaying. The typical application in the United States is
with dedicated power line carrier, which means that one channel is used for protective relaying only.
Single-sideband is used extensively in Europe and in “emerging growth countries” where many
functions (relaying, voice, data, etc.) are multiplexed at the audio level (1200 to 3000 Hz) over a
single RF channel (30 to 500 kHz). The trend in Europe [7] is now changing towards dedicated
carrier for relaying because fiber is taking over for generalized communications.
Methodology

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For this project we developed a high level idea and then worked down hierarchically to
develop the individual pieces. The idea is simple – support communication through power lines by
two parties. In Figure 1 we show the typical scenario of the Meter Man being used. We envision a
system, where the consumer would go to Meter Man’s interface [8] and choose to increase or
decrease his power consumption level, and Meter Man would send a signal to the electric company
advising them of the change in demand. Overall, this implementation would be perfect for the
distribution of power between two electric grids so that power outages could be avoided. For
example, let us consider the case of a large car manufacturer that will be increasing output by 40%
for five days. This would mean that the company would be using more power than usually expected.
This increased usage would cause extra load on the power grid. Now, if several other manufacturers
had similar demands then we would be in trouble. However, if the power company knew of the
increased demand, then they could compensate for the extra demand ahead of time by ensuring that
enough power is available.
II. BLOCK DIAGRAM
Fig 1.1 Block diagram
In this project the data is being transferred over AC line, which is encoded and decoded by
PLC modem [9]. In this the source information is generated by a key board and this will be sent to
destination through power line modem.. The receiving system will check the data and displays on the
LCD. The transmitter stage must be carefully designed to take digital signals from the MCU, filter
them to eliminate out of band emissions and drive the low impedance of the AC power line. In
receiver section of the power line module receive the data through the power line communication
modem [10] and send to the receiver section of the microcontroller unit and display on the LCD.
III. SIMULATION OF MODEM
Simulation of various analog circuits of modem is done using LtSpice. Mainly the analog
part of modem gets digital bits which becomes modulating signal for digital modulation circuits. In
the simulator ASK is used which is modulated by square wave i.e. equivalent of digital bit.
Simulated circuit is shown in fig 3.1 and the resultant simulated waveforms is shown in fig 3.2.
The ASK modulator is implemented using BC547 which is the first stage. High frequency
carrier is given to collector of transistor and base is given square wave signal. High frequency signal

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is 1st
signal starting from bottom in fig.3.2. Square wave signal is 2nd
from bottom in fig 3.2. If the
simulated circuit is very big simulation times will be too long and large numbers of results will be
present. This results in difficulties of making proper representations in the paper. In the actual
modem output of modulator goes to the signal interfacing circuit which superimposes high frequency
signal on power line. In the receiver section of modem interfacing device feeds high frequency signal
to the ASK demodulator. In the simulator Tx & Rx interfacing part is not shown. Directly
modulating signal is fed to ASK demodulator which is implemented with high frequency diode
detector. Output of diode detector is 3rd
signal from bottom in fig 3.2.High frequency capacitor filter
after diode detector will make all high frequency signal to go to ground. Output from this stage is 4th
from bottom in fig 3.2. Signal restoration is done using non inverting amplifier followed by Schmitt
trigger. Output of non inverting amplifier and output of Schmitt trigger is last but one and top most
waveform respectively in fig 3.2.
Fig 3.1. Circuit schematic of analog part of modem using LtSpice.
Fig 3.2. Simulated waveforms of circuit in Fig 3.1

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The modem at the transmission end modulates the signal from data terminal through RS- 232
interface onto the carrier signal in the power line[11]. At the receiving end, the modem recovers the
data from the power line carrier signal by demodulation and sends the data to data terminals through
RS-232 interface [1]. The data given to PLC module will be encoded into a carrier frequency of 120
KHz and modulated with 50Hz AC signal. (Frequency Modulation) .The modulated signal can travel
up to 1.5km through a live AC 230V power line.
The modulated AC signal is given to this module at AC terminals. Capacitors allows only
carrier frequency and blocks 50Hz signals, as XC = 1/2ПfC (Capacitor allows high frequency signal
and blocks low frequency signal). Two level capacitor based demodulation is done [12]. Inductors /
coils are used to block the high frequency signal, and bypasses the low frequency signals and derives
5V, 2A DC power source required for the module. (XL = 2ПfL. Inductor blocks high frequency
signals and allows low frequency signals). Therefore |Z| = 8Ω. However the input (and output)
impedance [13] varies in time, with different loads and locations. It can be as low as milli Ω and as
high as several thousands of Ω. So there is a chance of occurring impedance mismatch. Use of
filters will stabilize the network.
IV. IMPLEMENTATION
To visualize the working of power line modem visualizing of the data transfer is done using
human interface visualization. A keyboard is used as input device and LCD display is used as output
device. At higher level PC to PC communication is done. In the PC a hyper terminal will display the
key that is pressed and at the other end it will display the received message.
4.1 HEX KEYPAD
The hex keypad is a peripheral that connects to the DE2 through JP1 or JP2 via a 40-pin
ribbon Cable. It has 16 buttons in a 4 by 4 grid, labelled with the hexadecimal digits 0 to F. An
example of this can been seen in Figure 1, below. Internally, the structure of the hex keypad is very
simple. Wires run in vertical columns (we call them C0 to C3) and in horizontal rows (called R0 to
R3). These 8 wires are available externally, And will be connected to the lower 8 bits of the port.
Each key on the keypad is essentially a Switch that connects a row wire to a column wire. When a
key is pressed, it makes an electrical Connection between the row and column. The internal structure
of the hex keypad is shown in Figure 2. The specific mapping of hex keypad wires (C0 to C3 and R0
to R3) to pins is given in Table 1.
Figure 4.1. Hex keypad Figure 4.2. Hex keypad internal
wiring layout

30
Table 1: HEX key pad details
The keys just create a short between a row and column wire when pressed, but the row and
column wires all come from JP1 or JP2, rather than connecting to power or ground.
It is tempting to view the hex keypad as a peripheral which just tells us which key was
pressed, and all we have to do is read the value via the GPIO port. This is the wrong view to take.
The hex keypad is just a way for a user to interact with the DE2 board. As described in the previous
section, all the keypad does is make electrical connections between rows and columns - it is up to
your program to determine from that which key was pressed. The hex keypad is connected to the
DE2 Media Computer via the GPIO parallel ports. We need to remember a few things about the
GPIO ports in order to read and interpret hex keypad input properly.
Recall that each pin on JP1 or JP2 can be configured individually as input or output.
Furthermore, the port direction can be reconfigured by your program, so that the inputs and outputs
can be changed while your program is running. Finally, remember that each pin in the HEX keypad
is connected to a pull-up resistor, so any input coming from the hex keypad will read a 1 by default
(i.e. when a key is not being pressed).
These facts, coupled with our knowledge of how the row and column wires of the hex keypad
are wired up to the DE2 board, will allow us to determine which key has been pressed. If we treat all
the hex keypad wires as inputs, we will always read in a 0xFF, since there is nothing driving those
wires - they are unconnected. Even when a key is pressed, the effect is of connecting one input port
to another, so the pull-up resistors will always output a 1
The basic concept is that, since all the hex keypad wires are connected to JP1/JP2, we need to
use some of those wires to output values, and some to read in values. If we output values onto the
columns, say, then when we read from the rows, if a key is pressed there will be a short between a
row and a column and we will read in whatever value we have set the column to output. Rows in
which no key is pressed will be unconnected, and thus read in as a 1. Consequently, in order to be
able to differentiate between unconnected inputs and inputs for which a key has been pressed so that
they are reading the value put onto a column, we need to always output 0. Thus, we should write 0 to
all of the column wires, then read in from the row wires. If no key is pressed, the row wires will all
be unconnected, so the we will read a 1 value on pins 0 to 3 of JP1/2. However, if a key is pressed,
one of the row wires will be shorted with a column wire, and will thus have whatever value is on that
wire (i.e. 0). Thus, we can identify the row of which key was pressed by reading the row values and
finding which is 0.

31
This could also work if we treated the rows as outputs and the columns as inputs. In that case,
we would output 0 to the rows, and read in from the columns, and whichever column wire was 0
would indicate the column in which the pressed key resides. So, being able to identify the row or
column of a pressed key helps, but still does not tell us which key was pressed. The trick is that if
you know both the row and the column, you can determine which key was pressed from their
intersection. This means that we must take advantage of the ability to change the direction of the
individual pins of JP1/2 within our program. First, we set one half of the lower 8 bits as input (bits 0
to 3, say) and the other as output (bits 4 to 7), and get one value (the row, in this case), then we set
them the other way around, get the other value, and then we determine which key was pressed. So,
for example, if we read in that row wire R2 is 0 and column wire C3 is 0, we know that the B key on
the hex keypad was pressed. There are a number of different ways you can write code that will figure
out which key was pressed based on the row and column numbers Thus, to summarize, the following
steps should be followed in order to determine which key on the hex keypad has been pressed.
Table 2: Details of Hex key pad
STEPS PROCESS TO BE COMPLETED
1
JP1 or JP2 should be configured to have the pins connected to row wires R0 to
R3 Set as inputs. The pins connected to column wires C0 to C3 should be set as
Outputs. (That is, pins 0-3 are inputs, and 4-7 are outputs.)
2 The outputs (bits 4-7) should be set to 0.
3 Whichever input (bits 0-3) reads in as 0 indicates the row of the pressed key.
4
JP1/JP2 should then be reconfigured to have the pins connected to row wires
R0 to R3 set as outputs, and the pins connected to column wires C0 to C3 should
be Set as inputs. (That is, bits 0-3 are outputs, and 4-7 are inputs.)
4.2. SOFTWARE
Fig 4.3. Flow chart

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After successfully transferring key pressed information to display by using the power line
communication interface, the circuit was implemented for transferring data between two computers.
All the concepts are same except computers are used instead of key board and display. Message
display is done on the hyper terminal. This is shown below.
4.3. WORKING
This circuit contains key board, LCD display and microcontroller both side. We send the data
using program prepared in Embedded C through serial port. This serial port is connected to power
line communication module (PLM). This PLM is assigned supply of 230V mains. On the receiver
side, same circuit is connected to power line on the same phase. This circuit receives data which is
connected to pic 16F877A microcontroller. Whenever you press switch0, on the LCD screen it asks
to enter the data. After entering the data you have to press switch1 then the microcontroller reads the
data and transmits to the modem. This modem injects the data in power line. At the receiver side
same modem is used to decode the data and it is fed to microcontroller. Finally the message that you
entered is displayed on LCD.
In order to transmit the message first you have to plug in the power supply for both
transmitter and receiver. At the transmitter circuit, first to press sw0 (switch0) before that at the
receiving end lcd display shows some message like “HELLO IT IS DATA TRANSMISSION OVER
POWER LINE ” and After pressing sw0, the corresponding assigned data will be send to the power
line modem. After that it will be inserted into the power line by the power module
After pressing switch0 at transmitter, immediately at the receiver side the power module
takes the data from power line and processed by microcontroller after that received data send to the
LCD then LCD displays the data.
Fig 4.4. PC to PC communication using power line
Fig 4.5. PC to PC communication using power line

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Fig 4.6. Messages transferred through power line
V. RESULT AND DISCUSSION
Power line communication can be used for Remote control, Emergency alarms, Security
purpose, Messaging, Home and Industrial Automation.
ADVANTAGES
• It's inexpensive
• It uses existing electrical wiring.
• It provides Flexibility & Stability.
• It's easy to install.
• PLC solution is a complementary solution to traditional fixed line networks, wireless networks.
VI. CONCLUSION
PLC solutions may be seen as complementary or alternative solutions to traditional fixed line
networks, wireless networks and VDSL networks. According to existing network architectures,
buildings or technical constraints, either solution can be chosen, but one can also consider one
solution to complement another. PLC bandwidths are set to increase, the Hompelug AV standard is
being considered for broadcasting digital television. Many research projects are ongoing into these
solutions and their applications, it is all to come, and one should pay close attention to news about
this technology
REFERENCES
1. Power line communication by John Wiley volume 16 issue5
2. Hendrik C Ferreira and Olaf Hooijen, -Power Line Communications: An Overview,
Transactions of the S.A.Institute of Electrical Engineers
3. Broadband is Power: internet access through power line network, IEEE Communications
Magazine.
4. Comm. Eur. Union, “Smart grids technology platform. European technology platform for the
electricity networks of the future.” Belgium, EUR 22040, 2006. [Online]. Available:
www.smartgrids.eu

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5. N. Jenkins, J. B. Ekanayake, and C. Strbac, Distributed Generation. London, UK: IET Publ.,
2010.
6. D. Coll-Mayor, M. Paget, and E. Lightner, “Future intelligent power grids: Analysis of the
vision in the European Union and the United States,” Energy Policy, vol. 354, pp. 2453–
2465, 2007.
7. S. Galli, A. Scaglione, and Z.Wang, “For the grid and through the grid: The role of power
line communications in the smart grid,” Proc.IEEE, vol. 99, no. 6, pp. 998–1027, Jun. 2011.
8. S. Grenard, O. Devaux, O.Carre, & O.Huet, “Power steering,” IEEE Power Energy Mag. ,
vol. 9, no. 5, pp. 43–51, Sep./Oct. 2011.
9. S. Roy, D. Nordell, and S. S. Venkata, “Lines of communication,” IEEE Power Energy Mag.
, vol. 9, no. 5, pp. 65–73, Sep./Oct. 2011.
10. U.S. Dept. Energy, “A systems view of the modern grid: Integrated communications,” Feb.
2007.
11. V. C. Gungor and F. C. Lambert, “A survey on communication networks for electric system
automation,” Comput. Netw. vol. 50, pp. 877– 897, 2006.
12. IEEE Standard for Broadband over Power Line Networks: Medium Access Control and
Physical Layer Specifications, IEEE Standard 1901–2010, Sep. 2010.
13. A. Ametani, “A general formulation of impedance and admittance of cables,” IEEE Trans.
Power App. Syst. , vol. PAS-99, no. 3, pp. 902–910, May 1980.
14. Chinju K Sunil and Prathibha Varghese, “A Secured Data Transmission System by
Reversible Data Hiding with Scalable Compression” International journal of Electronics and
Communication Engineering &Technology (IJECET), Volume 5, Issue 12, 2014, pp. 84 - 92,
ISSN Print: 0976- 6464, ISSN Online: 0976 –6472.
15. Suvendu Chandan Nayak and Sasmita Parida, “An Approach For Secured Data Transmission
at Client End In Cloud Computing” International journal of Computer Engineering &
Technology (IJCET), Volume 4, Issue 4, 2013, pp. 381 - 389, ISSN Print: 0976 – 6367, ISSN
Online: 0976 – 6375.
16. Anu K George and Aby Mathew, “Remote-Control System of High Efficiency and Intelligent
Street Lighting Using Power Line Communication and Sensors” International journal of
Electronics and Communication Engineering &Technology (IJECET), Volume 5, Issue 12,
2014, pp. 112 - 117, ISSN Print: 0976- 6464, ISSN Online: 0976 –6472.

Data transmission through power line

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