design of power line communication system by

DESIGN OF POWER LINE COMMUNICATION

SYSTEM

By

ALAA ABDEL MONEIM SID AHMED

INDEX NO. 124022

SUPERVISOR

PROF. SHARIEF BABIKER

A thesis submitted in partial fulfillment for the degree of

B.Sc (HONS) in Electrical and Electronic Engineering

(ELECTRONICS AND COMPUTER SYSTEMS ENGINEERING)

University of Khartoum

Faculty of Engineering

OCTOPER 2017

ii

DECLARATION OF ORIGINALITY

I declare this report entitled “Design of Power Line Communication System” is my own work

except as cited in references. The report has been not accepted for any degree and it is not being

submitted currently in candidature for any degree or other reward.

Signature: ____________________

Name: _______________________

Date: ________________________

iii

ACKNOWLEDGMENT

I would like to express my deepest sense of gratitude to my supervisor Prof. Sharief Babiker

for both of his continuous advice, systematic guidance, encouragement and great efforts through

the course of this project.

I am deeply grateful to my project partner, Nuha Ahmed for her hard work, real team spirit,

continuous support, the unforgettable times we have spent and all good things we have learned

from each other.

I would like to thank Eng. Mahmoud Ibrahim for his grate helps, advices and

encouragements that support me.

One more personal note, I would like to express my love and gratitude from my deep heart

to my parents, my brother for teaching me values that are precious, irrespective of time and place

for their endless love, support and constant encouragement in all my endeavors.

iv

اهداء

..اميالى من جعلت للحياة معنى ولون.. من دونها ما كنت الكون هنا.. سيدة القلب والعقل.. وسيدة حياتي..

..ابي سندي..الى من اسقاني من حكمته حتى ما عدت ارى حياة ليس فيها.. علمني كيف تكون االمور..

وت احيانا.... صغيري وان قساخيالى

..ربىالى رفيقة الخمسة اعوام جليسة الوحشة والفرحة.. اختي التي لم تنجبها امي..

..نهىالى اعظم ما خرجت به من هذا المشروع..

..محمودعوني حين احتجته.. من كانالى

..سجى وتسنيمالى من تعانقت ارواحنا.. وان عز اللقاء.. اخواتي ورفيقات الدرب..

المقربين.. نكهة ايامي.. اجمل ما جادت لي به الدنيا.. ي واصدقائيصديقاتالى

..0124دفعتي الى من ما عدت اطيق تفرقهم..

v

ABSTRACT

Power lines and power system are designed to transmit power from the suppliers to the

customers at low frequency (50 Hz or 60 Hz) and high voltage (110 V, 220 V or 240 V).

Another utilization of power lines in improving the communication infrastructure is using

it as communication channel to transmit data at different high frequency ranges.

This project aims to design and implement Power Line Communication transceiver that

consist of transmitter, receiver and coupling circuit. Power lines are the communication channels.

Transmitter circuit modulate the data signal using one of the modulation techniques. This

project is using Frequency Shift Keying (FSK) modulation technique. Receiver on the other side

demodulate the modulated signal using Phase Locked Loop (PLL) technique in form of digital

data. In addition to modulation and demodulation transceiver perform multiple filtering and

amplifying operations in order to repair signals that have been attenuated and affected by the noise

after the transmission over power lines.

To enable the modulated signal to be injected into and extracted from the power line from

the two communication nodes, coupling circuit must be implemented in both sides. It also blocks

the power signal from entrance to the transceiver.

By applying this project data can be transmitted through the power lines in home

automation, automatic meter reading, broadband applications and many other applications.

vi

المستخلص

تستخدم منظومة الطاقة الكهربائية لنقل الطاقة الكهربائية من المنتجين )المولدات( الى المستهلكين عبر خطوط نقل

هيرتز. 60و 50الطاقة بترددات منخفضة تتراوح مابين

اتصال لنقل البيانات يمكن استخدام خطوط واسالك نقل الطاقة لتحسين جودة البنية التحتية لالتصاالت باستخدامها كقناة

بين اطراف االتصال المختلفة عبر نطاقات مختلفة من الترددات العالية.

يهدف هذا المشروع الى تصميم جهاز ارسال واستقبال باالضافة لدائرة االقتران. في هذه المنظومة تستخدم خطوط

قائمة بذاتها. نقل الطاقة كقناة اتصال. مما يقلل من التكلفة العالية النشاء شبكة اتصال

يستخدم هذا المشروع تقوم دائرة االرسال عن طريق استخدام احد تقنيات التشكيل بتعديل اشارة البيانات المراد ارسالها.

تقنية االرسال بازاحة الذبذبة لتعديل اشارة البيانات بما يسمح نقلها عبر خطوط الطاقة. وعلى الطرف االخر يقوم المستقبل بازلة

باالضافة لما سبق فان ( واعادتها الى بيانات رقمية.او دارة تثبيت الطورارة المرسلة باستخدام تقنية الطور المقفل )تشكيل االش

النظام يحتوي على دوائر تنقية وتضخيم متعددة العادة اصالح االشارات المرسلة والتي تأثرت بالضوضاء و تعرضت للتوهن

تصميم دائرة االقتران بقيم مكونات تسمح بحقن االشارة المشكلة واستخراجها من خطوط بعد انتقالها عبر خطوط نقل الطاقة. تم

الطاقة. كما ان هذه الدائرة تمنع وصول الفولتية المرتفعة المحمولة في خطوط نقل الطاقة الكهربائية ذات التردد المنخفض الى

نظام االرسال واالستقبال.

تفادة من شبكة خطوط نقل الطاقة الكهربائية الموجودة مسبقا في انشاء شبكة االسمن خالل تطبيق هذا المشروع يمكن

لنقل البيانات بترددات مختلفة مما يسمح باستخدامها في العديد من التطبيقات كأتمتتة المنازل، والقراءة التلقائية للعدادات، ونقل

بيانات االنترنت.

vii

TABLE OF CONTENTS

Declaration of originality .............................................................................................................................. ii

Acknowledgment ......................................................................................................................................... iii

iv ............................................................................................................................................................... اهداء

Abstract ......................................................................................................................................................... v

vi ........................................................................................................................................................ المستخلص

Table of contents ........................................................................................................................................ vii

List of Figures ............................................................................................................................................... xi

List of Tables ............................................................................................................................................... xii

List of abbreviation .....................................................................................................................................xiii

1 CHAPTER ONE: INTRODUCTION ........................................................................................................... 1

1.1 overview ........................................................................................................................................ 1

1.2 Problem statement ....................................................................................................................... 1

1.3 Project objectives .......................................................................................................................... 1

1.4 Thesis layout ................................................................................................................................. 1

2 CHAPTER TWO: LITRETURE REVIEW ..................................................................................................... 3

2.1 PLC history..................................................................................................................................... 3

2.2 PLC applications: ......................................................................................................................... 10

2.2.1 according to the frequency: ................................................................................................ 10

2.2.2 According to the voltage: .................................................................................................... 12

2.2.2.1 Low voltage or in-house: ................................................................................................. 13

2.2.2.1.1 Home automation: .................................................................................................... 13

2.2.2.1.2 Street lightening monitoring: .................................................................................... 13

2.2.2.1.3 Low cost inter-device peer-to-peer networking: ...................................................... 13

2.2.2.2 Medium Voltage and Low Voltage: ................................................................................. 13

2.2.2.2.1 Utility: ........................................................................................................................ 13

2.2.2.2.2 Broadband data transmission: .................................................................................. 14

2.3 PLC Types .................................................................................................................................... 14

2.3.1 Ultra-narrow band plc ......................................................................................................... 15

2.3.2 Narrowband plc................................................................................................................... 16

viii

2.3.3 Broadband plc ..................................................................................................................... 18

2.4 Plc standards ............................................................................................................................... 19

2.4.1 CENELEC .............................................................................................................................. 20

2.4.2 FCC ...................................................................................................................................... 21

2.4.3 IEEE ...................................................................................................................................... 21

2.4.4 IEC ....................................................................................................................................... 22

2.5 PLC protocols and Technologies ................................................................................................. 23

2.5.1 X-10 ..................................................................................................................................... 23

2.5.1.1 Protocol description ........................................................................................................ 23

2.5.1.2 Disadvantages ................................................................................................................. 25

2.5.2 CsBus technology ................................................................................................................ 25

2.5.3 LonWorks technology ......................................................................................................... 25

2.6 PLC system components ............................................................................................................. 26

2.6.1 Modem ................................................................................................................................ 26

2.6.1.1 Amplitude shift keying ASK ............................................................................................. 26

2.6.1.2 Phase Shift Keying ........................................................................................................... 27

2.6.1.3 Orthogonal Frequency Division Multiplexing (OFDM) .................................................... 28

2.6.1.4 Frequency Shift Keying .................................................................................................... 28

2.6.2 Coupling circuit ................................................................................................................... 29

Capacitive Coupling: ........................................................................................................................ 29

Inductive Coupling .......................................................................................................................... 29

3 CHAPTER THREE: METHODOLOGY AND DESIGN ................................................................................ 30

3.1 Design goals ................................................................................................................................ 30

3.2 System components .................................................................................................................... 30

3.2.1 PLC Transmitter ................................................................................................................... 30

3.2.2 PLC receiver ......................................................................................................................... 31


3.2.4 Decoupling circuit ............................................................................................................... 31

3.2.5 Power lines .......................................................................................................................... 31

3.3 Tools and instruments ................................................................................................................ 32

3.3.1 Software tools ..................................................................................................................... 32

ix

3.3.1.1 Proteus 8.6 ...................................................................................................................... 32

3.3.2 Hardware............................................................................................................................. 32

3.3.2.1 Oscilloscope .................................................................................................................... 32

3.3.2.2 Function generator ......................................................................................................... 33

3.3.2.3 Breadboard ..................................................................................................................... 34

3.3.2.4 Cpacitors and resistors .................................................................................................... 34

3.3.2.5 NPN transistors ............................................................................................................... 34

3.3.2.6 Opamps ........................................................................................................................... 35

3.3.2.7 VCO (lm566) .................................................................................................................... 35

3.3.2.8 PLL ................................................................................................................................... 35

3.3.2.9 Timer 555 ........................................................................................................................ 35

3.4 System design steps .................................................................................................................... 35

3.4.1 Step one: Generation of FSK signal ..................................................................................... 35

3.4.1.1 Design 1: Using Multiplexer ............................................................................................ 36

3.4.1.2 Design 2: Using 555 timer ............................................................................................... 37

3.4.1.3 Design three: using Voltage Controlled oscillator (VCO) LM566 .................................... 39

3.4.2 Step two: Demodulation ..................................................................................................... 42

3.4.2.1 Using Phase Locked Loop ................................................................................................ 42

3.4.3 Step three: coupling circuit ................................................................................................. 45

4 CHAPTER FOUR: RESULT AND DISCUSSION ....................................................................................... 48

4.1 Overview ..................................................................................................................................... 48

4.2 Calculations ................................................................................................................................. 48

4.2.1 FSK modulation ................................................................................................................... 48

4.2.1.1 For timer circuit ............................................................................................................... 48

4.2.1.2 For VCO circuit ................................................................................................................ 50

4.2.2 Demodulation using PLL:..................................................................................................... 52


4.3 Discussion .................................................................................................................................... 54

4.3.1 Modulation .......................................................................................................................... 54

4.3.2 Demodulation ..................................................................................................................... 56

4.3.3 Coupling .............................................................................................................................. 56

x

5 CHAPTER FIVE: CONCLUSION AND RECOMINDATIONS ...................................................................... 58

5.1 Conclusion ................................................................................................................................... 58

5.2 Problems and solutions ............................................................................................................... 58

5.3 Future works ............................................................................................................................... 59

References .................................................................................................................................................. 60

xi

LIST OF FIGURES

Figure 2.1: PLC system layers ...................................................................................................................... 20

Figure 2.2: Representation of the X-10 signal ............................................................................................. 24

Figure 2.3: tow packet of the X-10 protocol. .............................................................................................. 24

Figure 2.4: Amplitude Shift Keying .............................................................................................................. 27

Figure 2.5: Phase Shift Keying ..................................................................................................................... 27

Figure 3.1: Blocks of system components................................................................................................... 31

Figure 3.2: proteus 8.6 ................................................................................................................................ 32

Figure 3.3: oscilloscope ............................................................................................................................... 33

Figure 3.4: Function generator ................................................................................................................... 33

Figure 3.5: Breadboard ............................................................................................................................... 34

Figure 3.6: capacitors .................................................................................................................................. 34

Figure 3.7: Resistors .................................................................................................................................... 34

Figure 3.8: NPN transistor ........................................................................................................................... 34

Figure 3.9: VCO LM566 ............................................................................................................................... 35

Figure 3.10: FSK signal and data signal ....................................................................................................... 36

Figure 3.11: Multiplexor circuit ................................................................................................................... 37

Figure 3.12: 555 timer simulation ............................................................................................................... 38

Figure 3.13: Real Circuit .............................................................................................................................. 39

Figure 3.14: LM566 circuit simulation. ....................................................................................................... 41

Figure 3.15: LM566 circuit implementation ............................................................................................... 42

Figure 3.16: Block diagram of PLL. .............................................................................................................. 42

Figure 3.17: Phase Locked Loop components............................................................................................. 43

Figure 3.18: 4046 PLL simulation ................................................................................................................ 43

Figure 3.19: coupling circuit simulation. ..................................................................................................... 45

Figure 3.20: modulation circuit connected to coupling circuit. .................................................................. 47

Figure 3.21: demodulation circuit connected to coupling circuit. .............................................................. 47

Figure 4.1: timer circuit output ................................................................................................................... 49

Figure 4.2: timer circuit with prober values ............................................................................................... 49

Figure 4.3: real circuit result ....................................................................................................................... 50

Figure 4.4: FSK modulation output ............................................................................................................. 51

Figure 4.5: VCO final circuit simulation ....................................................................................................... 51

Figure 4.6: transceiver circuit ..................................................................................................................... 52

Figure 4.7: overall transceiver circuit results .............................................................................................. 53

Figure 4.8: coupling circuit result ................................................................................................................ 54

Figure 4.10: Mux good result ...................................................................................................................... 55

Figure 4.9: Mux bad result .......................................................................................................................... 55

file:///C:/Users/user/Downloads/thesisSemifinal.docx%23_Toc495837009



































xii

LIST OF TABLES

Table 2-1: Applications of PLC ..................................................................................................................... 12

Table 2-2: PLC Classifications ...................................................................................................................... 15

Table 2-3: Frequency band for NB-PLC ....................................................................................................... 17

Table 2-4: Industrial specification of BB-PLC .............................................................................................. 19

Table 2-5: CENELEC categories ................................................................................................................... 21

Table 4-1: coupling circuit parameters ....................................................................................................... 54

xiii

LIST OF ABBREVIATION

AC Alternating current

AM Amplitude Modulation

AMI Advanced Metering Infrastructure

AMR Automatic Meter Reading

AMRA Automatic Meter Reading Association

ANSI American National Standards Institute

ASK Amplitude Shift Keying

AT&T American Telephone and Telegraph

BBPLC Broad Band Power Line Communication

BPL Broad Band over Power Lies

BPSK Binary Phase Shift Keying

CSMA/CA Carrier sense multiple access with collision

avoidance

CTP Carrier Transmission over Power Line

DCSK Differential Chaos Shift Keying

DPSK Differential Phase Shift Keying

DQPSK Differential Quadrature Phase Shift Keying

DTOPL Data Transmission Over Power Lines

FCC Federal Communication Commission

FEC Forward Error Correction

FFH Fast Frequency Hopping

FSK Frequency Shift Keying

GE General Electric

HD High Definition

HV High Voltage

HVAC Heat Ventilation and Air Conditioning

IEC International Electrotechnical Commission

xiv

IEEE Institute of Electrical and Electronics

Engineers

ITU International Telecommunication Union

LAN Local Area Network

LMT Last Mile Telecommunication

LV Low Voltage

MAC Medium Access Control

MCM Multiple Carrier Modulation

MV Medium Voltage

NARUC National Association of Regulatory Utility

Commissioners

NBPLC Narrow Band Power Line Communication

OFDM Orthogonal Frequency Division Multiplexing

PLCC Power Line Communication Carrier

PLL Phase Locked Loop

PRIME Power Line Related Intelligent Metering

Evolution

PSK Phase Shift Keying

RCS Ripple Carrier Signaling

SDO Standards Developing Organization

SFSK Spread Frequency Shift Keying

TDMA Time Division Multiple Access

UNBPLC Ultra-Narrow Band Power Line

Communication

UPA Universal Power Line Association

VCO Voltage Controlled Oscillator

CHAPTER ONE INTRODUCTION

1

1 CHAPTER ONE:

INTRODUCTION

1.1 overview

the power line carrier communication system uses the existing AC electrical wiring as the

network medium to provide high speed network access points almost anywhere there is an AC

outlet.

1.2 Problem statement

Power lines were originally devised to transmit electric power from a small number of

sources (generators) to a large number pf sinks (consumers) in the frequency range of 50-60 Hz.

Nowadays with the emergence of modem networking technologies and the need for information

spreading, data transmission over power lines has seen a really big growth. The technologies

already used for spreading information such as telephone wiring, Ethernet cabling, fiber optic and

wireless have each its limitations in costs and reliability.

The advantage of using power lines for data transmission is that every building and home

is already equipped with the power line and connected to the power grid.

1.3 Project objectives

Study of the possibility and visibility of using power lines as a solution for sending

and receiving data.

Design power line communication system.

1.4 Thesis layout

This thesis is organized into 5 chapters:

Chapter 2 (Literature review): This chapter introduce the history of Power Line

Communication and its applications and types. Also it reviews the protocols and technologies used

in PLC.

CHAPTER ONE INTRODUCTION

2

Chapter 3 (Methodology and Design): This chapter describes the goals of designing such

a system, the system components, tools and instruments used and the steps of designing the PLC

system.

Chapter 4 (results and discussion): This chapter shows the results of the simulation

circuit design and the actual results of the real circuits. Also it discusses the results.

Chapter 5 (Conclusion): This chapter contains the thesis conclusion and expected future

works.

CHAPTER TWO LITRETURE REVIEW

3

2 CHAPTER TWO:

LITRETURE REVIEW

2.1 PLC history

The idea of utilizing power lines to carry signals is a very old invention. In 1838, the first

remote electricity supply metering was proposed to check the voltage levels of batteries in an

unmanned site of the London-Liverpool telegraph system. In 1897, the first PLC patent on power

line signaling electricity meter was proposed in Great Britain [1]. In 1905, the remote reading of

electricity meters using an additional signaling wire was patented in the USA. In 1913, the first

products of electromechanical meter repeaters were launched commercially.

In 1920, the carrier frequency transmission of voice signal over high voltage (HV) power

lines was deployed. The carrier transmission over power lines (CTP) was important for the

management and monitoring tasks and also at the beginning of electrification the full-coverage of

telephone network was not available. The frequencies used for CTP were between 15−500 kHz.

Under favorable circumstances, it was possible to bridge the distance of 900 k.m between

transmitter and receiver with the transmission power of 10 W (40 dBm). Firstly, only Amplitude

Modulation (AM) was applied as it was simple and optimal for voice transmission [1]. Later, the

telemetering and the telecontrolling systems were also implemented.

In 1927, the use of thermionic valves for metering was patented. From 1930 onwards, the

ripple carrier signaling (RCS) system was applied in the Medium Voltage (MV) and Low Voltage

(LV) networks where its main functions were the load distribution. It also made possible the

avoidance of extreme load peaks and made the load curve smooth. MV and LV networks have

large number of branches, so these were poor medium compared to the HV overhead lines. As

RCS worked in the low frequency range (approximately 125−3000 Hz), the transmission power

had to be according to the peak load of the network. Hence, the transmission power was large, in

practice it is around 0.1−0.5 % of the maximum apparent power. Here, the applied carrier

frequencies enabled the information to flow over transformers between MV and LV networks with

less attenuation. Also, the data rates were low and the data transmission was unidirectional as it is

from the power supply company to the consumers end. To transmit information through electrical


4

networks, RCS was used with the Amplitude Shift Keying (ASK- a type of amplitude modulation

that assigns bit values to discrete amplitude levels) as well as the Frequency Shift Keying (FSK- a

type of frequency modulation that assigns bit values to discrete frequency levels) methods [1].

In 1936, the indirectly heated cathode valve was introduced. In 1947, theinvention of

transistor reduced the size of all electrical and electronic devices. The invention of integrated

circuits in 1958-59 by Robert Noyce from Fairchild Semiconductor and Jack Kilby from Texas

Instruments and later the invention of microprocessor in 1971 by Ted Hoff at Intel launched the

development of low cost integrated circuits for power line carrier communications. Also by the

late 1980s and the early 1990s, sophisticated error control coding techniques and their

implementation into low cost microcontrollers within the hardware of PLC modems were

proposed.

The development of modulation methods and the use of higher frequencies in the carrier

signal enabled higher data transmission rates and decreased the required transmission power. Also

bidirectional data transmission was introduced and the benefits of using power lines for data

transmission indoors were implemented along with the introduction of Internet. Several

technologies concerned with PLC such as X10, MELKO™, LonWorks, CEBus, INSTEON and

HomePlug® were used during the last few decades.

The X10 standard was developed by Pico Electronics in 1975. X10 is an international and

open industry standard for communication of electronic devices used for home automation. It

mainly uses LV power lines for signaling and control. In this system, the digital data is encoded to

a 120 kHz carrier and is transmitted as bursts during zero crossings of AC voltage network. Here,

every single bit is transmitted at each zero crossing. Hence, data rates of 100 bps and 120 bps can

be obtained in 50 Hz and 60 Hz electric networks respectively.

The next generation devices were based on more effective modulation methods and those

provided higher data transfer rates and these were designed for load management in medium and

low voltage distribution networks. Here, the transmit power was decreased and it supported bi-

directional data transfer. The decrease in transmit power was achieved by increasing the carrier

signal’s frequency and using more sophisticated electronic devices. In 1984 the Enermet

MELKO™ system was published which utilized the Phase Shift Keying (PSK- a type of angle

modulation in which the phase of the carrier is discretely varied) modulation technique and


5

frequency band between 3025−4825 Hz for data transmission. Here, in MV and LV distribution

networks the data transmission rate of 50 bps was possible which were between a substation and

measurement or control units. As the frequency band was low and the carrier signal could pass 4

through the distribution transformers, bidirectional data transmission was possible by

MELKO™. However, its main applications were remote meter reading and load management.

The members of the Electronic Industries Alliance (EIA) realized the necessity of standards

that provides more capability than the X10. Hence, in 1992, they released the consumer electronic

bus (CEBus) standard which was also known as EIA-600. CEBus provides protocols to

communicate through power lines, twisted pairs, coaxial cables, infrared, RF, and fibre optics. It

used spread spectrum modulation technique on power lines within the frequency band of 100−400

kHz. CEBus was a packet-oriented, connectionless and peer-to-peer network which was intended

to transmit commands and data. It was mainly suitable for indoor applications.

In 1990, the Local Operation Networks (LonWorks) platform was created by Echelon. It

is a flexible, robust and expandable standard based on control networking platform. Here, the

physical layer (PHY) signaling can be implemented over twisted pair, power line, fibre optics and

radio frequency (RF). The LonWorks provides information based control systems in contrast to

the previous command based control systems. The LonWorks PLC technology have data

transmission rate of either 3.6 or 5.4 kbps depending on the frequency. Some applications of

LonWorks technology are lighting control, energy management, security and home automation

systems. The Universal Powerline Bus was introduced in 1999 by PCS Powerline Systems. It is a

protocol for communication among the devices used for home automation which uses power line

wiring for signaling and control.

In 2001, SmartLabs Inc. introduced a home automation networking technology called

INSTEON. It was developed for domestic control and sensing applications and was based on the

X10 standard. INSTEON technology is a dual band mesh topology which enables devices to be

networked together using power lines or radio frequency. Thereby it is less susceptible to the noise

interferences compared other single band networks. Here, PLC uses the frequency of 131.65 kHz

and binary phase shift keying (BPSK) modulationG.hn/G.9960 which is a home network

technology standard for high-speed networking over power lines, phone lines and coaxial cables

with data rates up to 1 Gbit/s.


6

Further, in 2008, a standard named IEEE 1675 was developed by Institute of Electrical and

Electronics Engineers (IEEE) standards association for broadband over power lines. It provided

electric utility authorities or companies a standard for safely installing the required hardware for

internet access capabilities over power lines. Subsequently, in 2009, the IEEE P1775 standard

concerned with electromagnetic compatibility requirements, testing and measurement methods for

powerline communication equipment is being completed by IEEE. Afterward, in 2011, the IEEE

1901 standard is published for high speed (up to 500 Mbit/s) communication devices via electric

power lines, hence called broadband over power lines (BPL). The standard uses transmission

frequencies below 100 MHz and it is usable by all classes of communication devices including

internet access services within a building for local area networks, smart energy applications,

transportation platforms (vehicle) and other data distribution applications less than 100m between

devices. It includes a mandatory coexistence inter system protocol which prevents interference

between different BPL implementations operated within close proximity. Moreover, in September

2011, the standards association of the IEEE published a standard named IEEE 2030 which

recognizes the interactive nature of the interconnection with the grid and all of its parts and realizes

the significance of the integration of power, communications and information technologies into

the smart grid (a modernized electrical grid that uses analogue or digital information and

communications technology) with interoperability of energy technology and information

technology operation with the electric power system, end-use applications and loads [2].Then, in

2013, IEEE standard association published a standard called IEEE 1905 which defines a network

enabler for home networking with support of both wireless and wire-line technologies. For IEEE

1905, the consumer certification program named nVoy was announced in June 2013 and consumer

level products were expected by year end 2013 but are delayed till 2014. On the other hand, the

Automated Meter Reading (AMR) system was firstly tested by AT&T Corporation (American

Telephone and Telegraph Corporation) in cooperation with a group of electric utilities in the USA

in 1968. It was a successful experiment and after this AT&T offered to provide AMR service

which was based on telephone communication link. However, from economical point of view, this

project was non profitable. In 1972, the General Electric (GE)’s corporate research center in

association with its meter department started a research and development attempt for a remote

meter reading system. Meanwhile, in 1977, at Rockwell International a utility communication

division had been introduced to develop distribution carrier communication systems. Later in


7

1984, General Electric achieved a license from Rockwell International to commercialize their

project of distribution line carrier product designs and technology for AMR.

From 1985, the modern era of AMR started as several full-scale projects of AMR were

implemented. Very firstly, the introduction of AMR technology was made by Hackensack Water

Corporation and Equitable Gas Corporation into their water and gas measurements systems

respectively. Following that, in 1986, the radio based AMR system was installed by Minnegasco

for 450,000 customers. Further, in 1987, Philadelphia Electric Co. had installed thousands of

distribution line carrier AMR units with the meters which were previously not accessible.

The primary implementation of the automation of meter reading was for reducing labor

costs and obtaining data that was difficult to obtain. Because of technical advance in solid-state

electronics, microprocessor components and communication sphere, a modern AMR system can

provide more useful information which are beneficial for distribution authorities and also enables

others additional services which is known as Smart Integrated Metering System. However, the

basic idea of remote electricity measurement is common for both AMR and Smart Integrated

Metering Systems. Originally AMR devices just collected meter readings electronically and

matched them with accounts. As technology has advanced, additional data could then be captured,

stored and transmitted to the main computer and often the metering devices could be controlled

remotely. This can include events alarms such as tamper, leak detection, low battery or reverse

flow. Many AMR devices can also capture interval data and log meter events. The logged data can

be used to collect or control the time of use or rate of use and that data can be used for energy or

water usage profiling, time of use billing, demand forecasting, demand response, rate of flow

recording, leak detection, flow monitoring, water and energy conservation enforcement, remote

shutoff, etc. Advanced Metering Infrastructure (AMI) represents the networking technology of

fixed network meter systems that go beyond AMR into remote utility management. The meters in

an AMI system are often referred to as Smart Meters, since they often can use the collected data

based on programmed logic.

In 2003, in Europe, the Northern Europe became the hotspot of Advanced Metering when

Sweden announced the decision to acquire monthly readings of all electricity meters by 2009. Soon

activities spread to the other Nordic countries like Finland, Denmark and Norway. In 2004, the

Essential Service Commission of Victoria, Australia has brought corrections to the electricity


8

customer metering code to implement an order in the installation of interval electronic meters for

Victorian electricity customers. According to the paper entitled "Mandatory Rollout of Interval

Meters for Electricity Customers" for all small businesses and residences, the meters have to be

installed by 2013, starting from the year 2006. It forecasts that, within seven years from the

beginning of the replacing, up to one million large and other customers will have upgraded meters.

However, by mid July 2013, the first Smart Meter in home displays was being made available to

Victorian consumers. At the beginning of 2014, over 2.5 million meters installed at homes and

small businesses across the state.

The United States (US) energy policy act of 2005 asked the electric utility regulators to

consider time-based rate schedule and enable the electric consumer to manage the energy use and

cost through advance metering and communication technology. Besides, in November 2005, the

Meridian Energy in New Zealand introduced the usage of smart meters in the Central Hawkes Bay

area for over 1000 households. The communication link was based on radio andmobile

technologies. It was expected to install over 6,300 smart meters by late 2006 as part of the initiated

experiment. In Italy, the world's largest smart meter deployment was undertaken by Enel SpA for

more than 30 million customers. Between 2000 and 2005, Enel SpA deployed smart meters to its

entire customer base. These meters are fully electronic and smart, with integrated bi-directional

communications, advanced power measurement and management capabilities with solid-state

design.

The Commonwealth issued a joint communiqué at the council of Australian Governments

meeting in Canberra in February 2006, committing all governments to the progressive rollout of

smart metering technology from 2007. In September 2006, the Netherlands government conducted

a cost benefit analysis of AMR for their country and proposed that all residential customers will

get a smart meter by the year 2013, starting from 2008. Since then, two utilities named Continuon

and Oxxio have been undertaking some pilot projects for the implementation of AMR. The smart

meter’s register electricity and communicate through PLC.

In February 2007, the Automatic Meter Reading Association (AMRA) endorses the

National Association of Regulatory Utility Commissioners (NARUC) resolution to eliminate

regulatory barriers to the broad implementation of Advanced Metering Infrastructure (AMI). The

resolution passed acknowledged the role of AMI in dynamic cost savings in revenue protection,


9

outage management and its benefits to the consumers. In June 2007, the Norwegian energy

authority declared that it would recommend new legislation for requiring smart meters to take

effect in 2013. Also in 2007, the Republic of Ireland pledged to introduce smart meters in every

home within a five-year period. In December 2007, the smart metering was included in the national

meter substitution plan of Spain for end users with an aim of remote energy management with a

deadline for the completion of the plan by 31st December, 2018. The Ontario Energy Board in

Ontario, Canada set a target of deploying smart meters to 800,000 homes and small businesses by

the end of 2007, which was surpassed, and throughout the province by the end of 2010In July

2008, from government of Australia the Advanced Metering Infrastructure was mandated and

being planned in Victoria for deployment of 2.6 million meters over a four-year period. Also in

2008, Austin Energy of Texas, United States began deploying approximately 260,000 residential

smart meters. According to the report from VaasaETT of October 2008, an energy think tank in

Helsinki, Finland found that smart meters are saving energy by around 10%. At the end of 2008,

the installed base of smart meters in Europe was about 39 million units, according to the analyst

firm Berg Insight.

In 2009, Florida Power and Light in United States began installing smart meters in the

Miami-Dade area for residential customers and it’s expected to be completed by 2013. In October

2009, the U.S. Department of Energy awarded $200 million grant for the deployment of

CenterPoint Energy's smart meter network in Texas. In December 2009, the United Kingdom's

Department of Energy announced its intention to have smart meters in all homes by 2020. Here,

the principal media of communication in the Home Area Network is ZigBee Smart Energy. ZigBee

is a specification for a suite of high level communication protocols used to create personal area

networks built from small, low power digital radios.

In January 2010, it was estimated to install 170,000 domestic smart meters in United

Kingdom and in October 2010, First Utility became the first energy supplier to offer smart meters

to all new and existing customers across the U.K. A smart metering pilot project named Linky was

conducted by Electricité Réseau Distribution, France involving 300,000 clients supplied by 7,000

low-voltage transformers. The experimentation phase started in March 2010. A key determining

factor will be the interoperability of the equipment of various suppliers. The general deployment

phase will start in 2016 and continue through 2020.


10

In January 2011, the American Council for an Energy-Efficient Economy reviewed more

than 36 different residential smart metering and feedback systems internationally. Their conclusion

was “To realize potential feedback induced savings, advanced meters must be used in conjunction

with in home displays and well-designed programs that successfully inform, engage, empower and

motivate people." In United States, Texas based CPS Energy has launched a pilot program with

40,000 smart meters deployed in the summer of 2011. CPS plans to complete the installation of

smart meters (electricity and gas) for all customers by the end of 2016.

The United Kingdom rollout is considered to be the largest program involving more than

27 million homes to replace meters for both gas and electricity. The rollout officially started in

2012 but some energy suppliers started installing smart meters in people's homes before this.

Besides, in spring 2012, Baltimore Gas and Electric of Maryland, United States began installing

or upgrading approximately two million electric and gas meters in every home and small business

in their service area. This process will take about three years to complete. These smart meters help

customers to manage their energy budgeting, tracking and save money. By July 2013, the first

Smart Meter in home displays was made available to Victorian consumers of Australia. At the

beginning of 2014 Smart Meter in home displays were spreading rapidly. By the end of 2014, in

United Kingdom the full rollout with the data communications for domestic customers are almost

completed. Most households will have smart meters installed by their energy providing

company/authority between 2015 and 2020, although some energy companies are starting to install

smart meters already.

2.2 PLC applications:

2.2.1 according to the frequency:

In accordance with the application, the axis is divided into three portions. Any portion is

suitable for some specific applications. The broadband PLC uses the frequency band between

1MHz and 300MHz. It is suitable for high data rate transmission, more than 10Mbps. The

NBPLC’s portion uses the CENELEC bands for low data rate transmission, less than 50kbps. Over

the frequencies from 145.3kHz to 500kHz, the NBPLC’s technologies are used to perform high

data rate transmission between 50 kbps and 1 Mbps. Thereby, the applications of the power line

communications technology are related to the frequency band used. The applications of BBPLC


11

cannot be deployed over NBPLC frequencies. The deployment of the technology over each range

of frequencies is supported by many companies and organizations. Table (2-1) gives some

specifications on the application of the power line communications technology. It shows the

frequency band, some modulation schemes proposed by the SDOs for both NBPLC and BBPLC.

The complexity of the forward error correction (FEC), the access method and some companies and

organizations supporting the standards are also mentioned. The NBPLC frequency bands are used

for metering, lighting, energy and grid management.

The BBPLC frequency band is used for applications such as last mile telecom, voice over

IP and high definition television. Companies such as Gorlitz and alliances such as G3-PLC,

PRIME are specialized in meter manufacturing. The KNX organization is the standard for home

and building control.


12

Table 2-1: Applications of PLC

UNBPLC NBPLC BBPLC

Frequency 3~148.5 KHz 145.3~478.125 KHz 1~300 MHz

Modulation and

Coding

FSK, BPSK, FFH (Fast

Frequency Hopping),

SFSK (dual ch/spread

FSK), DCSK diff chrip

shift keying

DBPSK, DQPSK,

OFDM, MCM

(Multiple carrier

modulation)

MCM/COFDM Bit

loading

FEC Low complexity and

reliability

Strong, hirgh

reliability design

Medium Maximum

throughput

Access CSMA/CA, TDMA CSMA/CA, TDMA CSMA/CA, TDMA

Transport layer IPv6, IPv4, Ethernet IPv6, IPv4, Ethernet IPv6, IPv4, Ethernet

Applications Automatic meter AMR,

Power line area network

Airfield lighting,

Energy

management, Smart

Grid application and

metering, ARM

Last Mile Telecom

(LMT), Internet,

VoIP, IH networking,

High definition TV

(HD TV)

2.2.2 According to the voltage:

The applications are very wide and we can divide them into two categories: The Medium

Voltage or access technology mainly used by the utility authority, the Low Voltage or in home

which cover the area of sending data over power lines within the consumer’s side and extends to

all the electrical outlets within the home.


13

2.2.2.1 Low voltage or in-house:

2.2.2.1.1 Home automation:

Many years ago control of appliances in the home used to call for the establishment of new

cable wiring in the home. With the DTOPL technology automation of a building can be done using

power lines only. Hence we can control home appliances, light switches, wall outlets, thermostats,

Heat Ventilation and Air Conditioning systems (HVAC), sensors, alarm and security. One of our

project goals is to implement the home automation.

2.2.2.1.2 Street lightening monitoring:

The use of DTOPL to monitor street lights leads to big savings in the electricity bill of the

government by introducing selective dimming or selective turn-off features. This application can

increase energy savings by 25%.

2.2.2.1.3 Low cost inter-device peer-to-peer networking:

Power lines may be used to create a network that links devices together on the power grid.

Since such a network makes use of the existing infrastructure, installation time and cost are

virtually non-existent. Also since every outlet or junction box becomes a point where a device may

be connected, the device can be moved around numerous times. An example of such a network

can be to replace the RS232 wiring required to set audio and video inputs on various systems in a

house or a building.

2.2.2.2 Medium Voltage and Low Voltage:

2.2.2.2.1 Utility:

Automatic Meter Reading is a technology that uses the power line to send

information to the utility directly. Meters can be linked to concentrators to allow

suppliers to have remote access to each individual meter, to read or write

information such as rates, pre-paid amounts, current and cumulative counts,

tampering detection, etc. Meters and/or concentrators can also be used along

with AC Remote LCD devices to replicate and distribute their information to

one or more points located anywhere on the electrical network.

Load shedding: this is done when we need to reduce power given to loads when

we have peak demands hours. As an example incandescent lights, with the help


14

of a load control circuit will receive less power when the utility notices that the

demand for electricity is at its peak in certain periods.

2.2.2.2.2 Broadband data transmission:

This developing technology which is at its testing level (Italy, USA) nowadays enables

broadband internet to be provided to your home using the electrical grid. This feature is behind the

scope of our project however we will give a brief overview of what this technology is about:

An example of a company developing this technology is ABB Medium Voltage Power

Solution. This system certified for use up to 24 KV provides data transfer rates of up to 10 Mbps

and hence challenging the xDSL and the broadband cable technology. The main problem in this

technology is the connection between the MV and the LV grid which is done using optical fibers,

copper pairs or wireless[3].[4].

2.3 PLC Types

Power Line Communication (PLC) which uses power cable as communication media has

received attention as a candidate communication technology for smart power system. PLC is not

a new technology. Utility companies have used PLC for metering and control of applications for

several decades. PLC which has been used for this purpose has few bps of data rate and used a

narrow band frequency. PLC is only a wire technology which can compete with wireless

technologies economically because cost for cable deployment is not necessary. Also PLC can

support ubiquitous solution with distributed power grid. PLC can be classified in three types

through the use of frequency band. Table 2.1 shows summary of these three types of PLC.


15

Table 2-2: PLC Classifications

Classification Frequency band Data rate Applications

Ultra-Narrowband

PLC

(UNB-PLC)

~3 KHz Hundreds bps Control, AMR

Narrowband PLC

(NB-PLC)

3~500 KHz 10s ~ 500 kbps Control, Smart

metering

Broadband PLC 1.8~250 MHz Over 1 Mbps Data, Multimedia

Communication.

2.3.1 Ultra-narrow band plc

Ultra-Narrowband Power Line Communication (UNB-PLC) is operated at a frequency

band of below 3kHz. The data rate of UNB-PLC is very low (hundreds bps), however, the

communication range is over 150 km. UNB-PLC has been used for automation for distributed

facilities and Automatic Meter Reading (AMR) solution for several decades. Though it has many

advantages such as maturity of technology, cost and communication range, the usage of UNB-

PLC has been restricted field due to a low data rate. UNB-PLC can be a good candidate technology

for WAN just considering its operating range. UNBPLC may not be considered for communication

Infrastructure of Micro Grid because Micro Grid covers only a small area.

The earliest PLC systems are ripple control systems, first introduced in the 1930s, and still

used in parts of Europe and New Zealand to provide basic low bandwidth direct load control and

other telemetry. These use basic modulation schemes on a lower frequency carrier to convey

information.

Another approach used since the 1970s leverages the fundamental alternating current (AC)

frequency (50-60 Hz) as a carrier to transmit information on the power line. As a result, these

systems avoid many of the noise and attenuation issues of other PLC technologies (which impose


16

other carrier frequencies) and can be transmitted across long distances and through transformers

without repeaters. The leading example of this is Two-Way Automatic Communications System

(TWACS – today known as Aclara PLC). These systems also deliver 10 to 100 bits per second

data rates.

Low-speed PLC systems have been widely deployed for remote meter reading and direct

load control applications.

2.3.2 Narrowband plc

Narrowband Power Line Communication (NB-PLC) uses 3 ~ 500Khz frequency band and

supports several hundred bps of data rate. Industry and academia have paid attention to the

technology of NB-PLC recently. PLC has a harsh channel circumstance like that of a wireless

communication and it also has a problem of electromagnetic compatibility (EMC). Using a wide

frequency band can increase the data rate of PLC which is called Broadband PLC but many

concerns like interference, attenuation and frequency regulation should be considered to support a

robust communication services. Using narrow frequency band can release the mentioned problems

although NB-PLC has a low data rate. For this reason, NB-PLC has got more attention comparing

with PLC using wide frequency band nowadays. The frequency band for NB-PLC is shown in

Table 2-2. These rates are appropriate for telemetry and control applications. In North America,

Japan and China, the frequency range of up to 500 kHz are viable under local regulations for N-

PLC and offers a reasonably wide communications bandwidth (up to above 300Kbps) and a

broader range of applications can be considered. There are many different implementations, with

varying data rates, modulation schemes, and degrees of adherence.


17

Table 2-3: Frequency band for NB-PLC

Region Institution Frequency

Europe

CENELEC

(European Committee for

Electro-technical

Standardization)

A: 3~95 KHz

B: 95~125 KHz

C: 125~140 KHz

D: 140~148.5 KHz

USA

FCC

(Federal Communications

Commission)

10~490 KHz

Japan

ARRIB

(association of Radio

Industries and Business)

10~450 KHz

PRIME (Powerline Related Intelligent Metering Evolution), an OFDB based NB-PLC

specification which started from 2007 uses CENELEC A frequency band and supports 125 kbps

of data rate. G3-PLC which was released at 2009 is also an OFDM based NB-PLC specification

with frequency band from 10 to 490KHz. The maximum data rate of G3-PLC is 46 kbps. Though

both specification uses OFDM with DPSK modulation, the PRIME is originally designed for

Metering through LV (Low Voltage) power grid and G3-PLC is designed for smart grid

considering MV (Medium voltage) power grid and transformer which has a high noise and

attenuation. Therefore, G3-PLC has a lower data rate compared with PRIME, however, G3-PLC

has a higher robustness. Standardization for NBPLC has been started from 2010. IEEE1901.2 and

ITU-T G.hnem have been designed for applications for smart grid. Both standards support

communication through LV power cable, MV power cable and transformers with up to 500 kbps


18

data rate. NB-PLC with LV and MV power cable may be great candidates for communication

technology for the NAN in Micro Grid.

2.3.3 Broadband plc

Broadband Power Line Communication (BB-PLC) is a technology for high speed data

communication with a frequency range of 1.8 MHz ~ 250 MHz. In the early 2000, several

industrial specifications of BB-PLC especially for home network & video transmission have been

released. These industrial specifications are explained at Table 2-3.

BPL technologies generally operate at carrier frequencies well above the CENELEC bands

and therefore experience inconsistent and extremely challenging spectrum characteristics. Not

only has reliable communications been hard to achieve, but these systems have also caused

significant electromagnetic interference problems.

All three BB-PLC specifications use CSMA/CA MAC (Medium Access Control) scheme

and support around 200Mbps physical throughput. All these specifications have been designed for

HAN. These three industrial specifications have many similar aspects, however, they do not

support interoperability. Recently released BB-PLC specification HomePlug AV2 supports up to

1Gbps transmission rate with MIMO. In 2010 IEEE1901 standard for BB-PLC has been released.

IEEE1901 supports two modes of BB-PLC. One is OFDM based PHY/MAC scheme which is

compatible with HomePlug AV specification and the other is wavelet OFDM based PHY/MAC

scheme compatible with HD-PLC specification. IEEE1901 standard also can get up to 200 Mbps

physical throughput. ITU-T also released ITU-T G.hn standard for home networking. ITU-T G.hn

is standard for all wired communication technologies for homes such as Power line (PLC), Phone

line and coaxial cable with up to 1 Gbps bit rate. BB-PLC can support high data rate for data

communication but transmission range is limited (around 100m). Therefore, BB-PLC can be a

great technology for HAN however to use for NAN, the help of other facilities like a repeater may

be necessary.[5]


19

Table 2-4: Industrial specification of BB-PLC

Alliance Frequency

Band

Throughput Modulation Chip set

Maker

HomePlug

(Homeplug Power Line Alliance)

1.8 ~ 30

MHz

200 Mbps OFDM Intellon

(Qualcomm)

UPA

(Universal Powerline

Association)

3~33 MHz 200 Mbps OFDM DS2

(Marvell)

HD-PLC

(High Definition Powerline

Communication)

2~28 MHz 210 Mbps Wavelet

OFDM

Panasonic

2.4 Plc standards

When using the powerline as a channel certain standards and regulations must be followed

in order to avoid interference between the frequencies transmitted with any other frequencies

already existing. Hence the bandwidth in the DTOPL environment is not limited by physical

capabilities of the line. Rather, regulatory authorities in the developed countries limit the available

bandwidth in order to prevent radio interference, other devices interference or military bandwidth

interference. The standards in power line communications (PLC) calibrate

parameters such as frequencies allocation, signal level, security, topology of the

network and many others parameters. In power line communications

(PLC), the SDOs focus on the physical (PHY) and on the data link (DLL) layers as shown

on Fig (2.1). The other layers are reserved for the application.


20

Here we will discuss the limiting standards CENELEC, FCC, IEEE and IEC governing

data transmission over power lines.

2.4.1 CENELEC

For Western Europe CENELEC’s standard EN50065 [6] “Low voltage mains signaling”

gives regulations on key parameters such as frequency range, signal power and so on. The standard

allows signals to operate in the frequency band 3- 148.5kHz, avoiding interference with ripple

control systems at the lower boundary, and interference with long wave (LW) and medium wave

(MW) radio broadcasts by posting the upper boundary. CENELEC then divide this band into

further categories:

• A-band (3 kHz - 95 kHz)

• B-band (95 kHz - 125 kHz)

• C-band (125 kHz - 140 kHz)

• D-band (140 kHz - 148.5 kHz)

Figure 2.1: PLC system layers


21

We can see frequency ranges and maximum transmission levels for power line communication

according to CENELEC 50065-1 standard

Table 2-5: CENELEC categories

Band Frequency range Maximum

transmission level

Usage areas

A 3khz -95 khz 134db (μV) Available for electric distribution

companies use only

B 95khz -

125khz

116db (μV) -

134db (μV)

Available for consumers with no

restriction

C 125khz -

140khz

116db (μV) -

134db (μV)

Available for consumes only with

media access protocol

D 140khz -

148.5khz

116db (μV) -

134db (μV)

Available for consumers with no

restriction

2.4.2 FCC

For North America the Federal Communications Commission (FCC) regulates transmitted

power and bandwidth. The frequency range in this standard is from 100 to 450 KHz which is

higher than the CENELEC. Moreover, Part 15 of the American FCC’s rule allows transmission

over power lines outside the AM frequency band (535 to 1705 KHz).

2.4.3 IEEE

The Institute of Electrical and Electronics Engineers [8] have published a set of

recommendations and standards pertaining to the power line communication available at the

reference: http:://standards.ieee.org/catalog/olis/psystcomm.html.


22

2.4.4 IEC

The International Electrotechnical Commission (IEC) [9] has standardized the distribution

line communications through technical committee #57 working group 9. In this standard, IEC

TC57/WG9 uses frequencies below 150 KHz.

IEC 61334, known as Distribution automation using distribution line carrier systems,

is a standard for low-speed reliable power line communications by electricity meters, water meters

and SCADA. It is actually a series of standards describing the researched physical environment of

power lines, a well-adapted physical layer, a workable low-power media access layer, and a

management interface.

G3-PLC, Powerline, intelligent metering evolution (PRIME), the American national

standards institute (ANSI), KNX and HOMEPLUG are some groups and alliances that develop

and deploy standards and technologies in power line communications sector.

The HomePlug Alliance is an association of companies within the electric utility industry

in the United States. The companies include Cogency, Panasonic, Radio Shack Corp. and Sharp.

Twenty participating member companies accompany this group and some of the big players

include Motorola, Philips Electronics, Sony Corp. and France Telecom. The HomePlug Alliance

developed the HomePlug standard and they meet the current FCC Part 15 requirements for current

carrier systems. The aim of the HomePlug standard is to provide interoperability between

consumer devices by setting a MAC protocol as well as the physical signaling techniques to be

used a form of orthogonal frequency division multiplexing (OFDM) modulation using up to 76

carriers in the band 4.5 MHz to 21 MHz. The throughput rate of a typical HomePlug standard is

14 Mbps with extrapolated rates going up to 20 Mbps. G3-PLC, PRIME, ANSI and KNX propose

technologies using the CENELEC’s frequency bands. G3-PLC works on the range between

35kHz–90 kHz while PRIME alliance uses the frequency band 42 kHz–90 kHz. ANSI proposes

technologies for the frequencies from 86 kHz–131 kHz and KNX works with the band of

frequencies between 125 kHz to 140 kHz. HomePlug is present over the whole PLC’s frequency

band.[3][6]


23

2.5 PLC protocols and Technologies

The technologies and standards used presently in the Power Line Communications are

investigated in depth. These include LonWorks, X-10, OFDM, Passport CEBus and the HomePlug

standard. Then focus was on the technologies that are being deployed based on the standards. The

advantages and benefits of using Power Line as the medium of data transmission at homes was

also considered. The quality of service, data transmission rates, the limitations, the drawbacks and

other important factors were taken into account. The description of technologies follows.

2.5.1 X-10

It is the most ancient communication protocol used in home networking since 1978

developed by X-10 US Corporation. It is used to allow compatible devices to communicate with

each other over 110V AC wiring.

2.5.1.1 Protocol description

X-10 simply provides the technical specifications of how a device should place a signal onto the

power line. The X-10 technology transmits binary data using the amplitude modulation technique.

In order to differentiate the data symbols the carrier uses the zero voltage crossing point of the 60

Hz on the negative or positive cycle.

Hence for synchronization, the presence of a 120 kHz signal burst at the zero crossing indicates

the transmission of a binary one, whilst the absence of the 120 kHz signal indicates a binary zero.


24

X-10 contains a

detailed addressing

scheme to prevent device clash. Devices contain two addresses - a house (dwelling) address, and

then an individual device address. A typical X-10 transmission would include a start code, house

address, device address, and then function code (such as ON, OFF, etc.). The X-10 system is

limited in that it does not easily provide for two-way communications, and is very slow, although

adequate for simple home automation tasks. Every bit requires a full 60 Hertz cycle and thus the

X-10 transmission rate is limited to only 60 bps. Usually a complete X-10 command consists of

two packets with a 3-cycle gap between each packet. Each packet contains two identical messages

of 11 bits (or 11 cycles) each. A complete X-10 command consumes 47 cycles that yield a

transmission time of about 0.8.

Figure 2.2: Representation of the X-10 signal

Figure 2.3: tow packet of the X-10 protocol.


25

2.5.1.2 Disadvantages

The X-10 technology would not fit our project design for the main fact that it has limited

potential in speed and intelligence terms. Its low data rate and undeveloped functionality permit to

use the X-10 technology in limited applications. In addition to its unreliability of amplitude

modulation and error correction, X-10 operates on 110V AC, which is a major drawback for its

use.

2.5.2 CsBus technology

CEBus, or Consumer Electronics Bus, a standard proposed by the Electronic Industries

Association, is based on the concept of Local Area Networks (LAN’s), for the home. CEBus based

products consist mainly of two components: a transceiver which implements spread spectrum

technology along with a controller to run the protocol. The given protocol standards are for radio

frequency, twisted pair, power line communication and a number of other home networking

methods. The CEBus DTOPL standard specifies that a binary digit is represented by how long a

frequency burst is applied to the channel. For example, a binary ‘1’ is represented by a 100

microsecond burst, whilst a binary ‘0’ is represented by a 200 microsecond burst. Consequently,

the CEBus transmission rate varies with how many ‘0’ characters, and how many ‘1’ characters

are transmitted. The CEBus standard specifies a language of object oriented controls including

commands for volume up/down, temperature up one degree, etc. Due to the high noise level of

power line channels, data should be transmitted via short frames, which is assured by the use of

the spread spectrum technology. CEBus protocol uses a Carrier Sense Multiple Access/Collision

Detection and Resolution (CSMA/CDCR) protocol to avoid data collisions. CEBus is a

commercially owned protocol, and thus attracts registration fees.

2.5.3 LonWorks technology

This technology has been developed by Echelon Corporation [4]. It is essentially structured

as an automatic control system that consists of sensors, actuators, application programs,

communication networks, human-machine interface and network management tools. LonWorks

(Local Operation Networks) technology is an important new solution for control networks


26

developed by Echelon ® Corporation. A control network is any group of devices working in a

peer-to-peer fashion to monitor the different components cited above. In some ways, a

LONWORKS control network resembles LAN. It can control and link factory conveyor belts,

product inventory, and distribution systems for optimum efficiency and flexibility. Smart office

buildings can turn lights on and off, open and lock doors, start and stop elevators, and connect all

functions to a central security system. In the same manner, homeowners can program a vast array

of products and conveniences, from sprinkler systems to VCRs, with a touch tone phone from any

remote location. The LonTalk communications protocol is a layered, packet-based, serial peer-to-

peer communications protocol. This protocol is designed for the requirements of control systems,

rather than data processing systems. Also, this protocol is media-independent, which allows the

system to communicate over any physical transport media. LonTalk has been approved as an open

industry standard by the American National Standards Institute (ANSI)-EIA 709.1.[7][6]

2.6 PLC system components

Plc system main components can be classified as:

Plc modem

Coupling circuit

Power supply

Controller

2.6.1 Modem

Modulation is process for moving a signal in a transmission medium via a high frequency

periodic signal. High frequency signal called carrier frequency [1]. Data signal can change of

carrier frequency’s amplitude, frequency or phase values. Here we are going to discuss only digital

modulation techniques:

2.6.1.1 Amplitude shift keying ASK

At amplitude shift keying, every bits changes the carrier signal’s amplitude. If the data bit

is logic “1” then output is equal to carrier signal otherwise output is zero. ASK is so sensitive for


27

noise and propagation conditions. ASK is inexpensive and simple modulation type than other

modulation types. This modulation is shown in figure (2.4).

2.6.1.2 Phase Shift Keying

At phase shift keying, the data bits change the carrier signal’s phase. Generally, PSK uses

two different angles for communication. For instance, if the data signal’s bit digital “0” output

sinusoidal wave’s phase angle 0º and for digital “1” phase angle 180º. So two different angles can

transmit 1 bit and four or more angle can transmit 2 or more bit at 1-cycle. Quadrature Phase-Shift

Keying (QPSK) uses four phase and QPSK is the most known PSK type. Bluetooth, wireless

modems, satellite TV receivers and RFID cards uses advanced PSK types. This modulation is

shown in Figure (2.5).

Figure 2.4: Amplitude Shift Keying

Figure 2.5: Phase Shift Keying


28

2.6.1.3 Orthogonal Frequency Division Multiplexing (OFDM)

modulation techniques transmit data via a series of parallel subcarriers set at different

frequencies. In theory they allow high-bandwidth levels, but in practice a great deal of bandwidth

is lost under noisy conditions over low-voltage networks. On top of that, OFDM can prove costly

to implement and draws significant power to operate.

2.6.1.4 Frequency Shift Keying

At frequency shift keying, the data signal’s every bit changes the carrier signal’s frequency.

FSK has many application areas in our daily-life (e.g. radio, modem, fax). FSK is very immune to

noise. Because noise can change the signals amplitude but it can’t change the signals frequency

easily. Particularly resilient to narrowband interference, Spread-Frequency Shift Keying (S-FSK)

modulation as described by IEC 61334 transmits data through discrete frequency changes in the

carrier wave. Though it supports lower data rates than OFDM, these rates are still more than

sufficient for smart metering applications. This modulation technique is capable of robust

communication, as well as being cheaper to implement and drawing limited power.

On this basis it seems that S-FSK, with its lack of complexity, greater commercial viability,

and reliable track record in the field, is destined to see greater first-phase PLC deployment than

the alternative modulation options. In this project FSK is used in transmitter side.

Therefore, at the receiver, we have to recover the FSK signal to digital signal, that means the

frequency should be converted back to voltage. We use phase locked loop (PLL) as FSK demodulator.

PLL is a kind of automatic tracking system, which is able to detect the input signal frequency and

phase. PLL is widely used in wireless applications, such as AM demodulator, FM demodulator,

frequency selector and so on. In the digital communications, various types of digital PLLs are

developed. Digital PLL is very useful in carrier synchronization, bit synchronization and digital

demodulation. In figure, when the input signal frequency changes, the output signal of the phase

detector will change and so as well as the output voltage. We can use this characteristic to design the

FSK demodulator. Let the FSK signal frequencies as f1 and f2, then these signals are inputted to the


29

input terminal of figure. When the input signal frequency is f1, the output voltage will be V1. When the

input signal frequency is f2, the output voltage is V2. At this moment, we have converted the frequency

to voltage. If we add a comparator at the output terminal of PLL, the reference voltage will lie between

V1 and V2, then at the output terminal of comparator, we are able to obtain the digital signal, which is

the demodulated FSK signal.[8]

2.6.2 Coupling circuit

The biggest technical challenge in a power line carrier is to couple the low voltage and

high frequency carrier set to the high voltage and low frequency power line. The carrier signal is

injected on the power line through the coupling network.

There are two methods of connecting the power line communication module into the

network:

Capacitive Coupling: A capacitor is responsible for the actual coupling and the signal is

modulated onto the network’s voltage waveform.

Inductive Coupling: An inductor is used to couple the signal onto the network’s current

waveform. Inductive coupling some time is rather noisy, however, the advantage is, no physical

connection to the network has to be made. Thus make it safer to install as compare to capacitive

coupling.

When designing the coupling circuit, two major types of components as described in the

table below should be considered. Another important feature to take notes is the protective coupler

circuitry.[9] [10]

CHAPTER THREE METHODOLOGY AND DESIGN

30

3 CHAPTER THREE:

METHODOLOGY AND DESIGN

This chapter present design and development process to come up with our plc final system.

3.1 Design goals

We aimed to design a system that transmit digital data from the sender to the receiver using

power lines as communication channel. The transmission system has to convert the information data

in a suitable form before it is injected in the communication channel. There are several multiplex and

modulation schemes which are investigated to be applied in the PLC transmission systems. The

frequency of the carrier signal should be much higher than the frequency of the 220 V signal

(50Hz) to avoid the interference between these two signals. PLC circuit must be insulated from

power line, which is very important for human health and for the operation of the circuit. For this

purpose, a coupling circuit must be designed to inject the modulated signal into the power line and

block the AC mains signal preventing it from reaching the input of modem communication system.

On the other side, the modulated signal must be extracted from the power line using the

coupling circuit. The receiver must recover the digital data from the modulated signal through

applying one of the demodulation techniques.

Transceiver system must include filters to avoid the noise and attenuation caused by using

power lines as communication channel.

3.2 System components

3.2.1 PLC Transmitter

Our transmitter consists of a chip that modulate the digital signal using FSK modulation

technique. Generating FSK signal can be done by different types of chips after investigation and

number of experiments (555 timer, multiplexer, XR-2200, LM566) LM566 VCO was used .

transmitter. Also contains filters and amplifiers to amplify the small modulated signal that

produced by the chip.


31

3.2.2 PLC receiver

The circuit consist of many filters to block the noise and amplifiers to amplify the

modulated signal after propagating through the power line.


We use a simple coupling circuit. That consist of a coupling capacitor and transformer.

3.2.4 Decoupling circuit

It is the same as the coupling circuit but at the receiver.

3.2.5 Power lines

The communication channel that we used to transmit the data.

Figure 3.1: Blocks of system components


32

3.3 Tools and instruments

3.3.1 Software tools

3.3.1.1 Proteus 8.6

Was used to simulate the actual circuit.

3.3.2 Hardware

3.3.2.1 Oscilloscope

We used it to monitor the output from the modulation and demodulation circuits.

Figure 3.2: proteus 8.6


33

3.3.2.2 Function generator

In one of our experiments we use function generator to produce two signals with different

two frequencies.

Figure 3.3: oscilloscope

Figure 3.4: Function generator


34

3.3.2.3 Breadboard

a construction base for prototyping of electronic circuits.

3.3.2.4 Cpacitors and resistors

3.3.2.5 NPN transistors

Figure 3.5: Breadboard

Figure 3.6: capacitors Figure 3.7: Resistors

Figure 3.8: NPN transistor


35

3.3.2.6 Opamps

3.3.2.7 VCO (lm566)

Voltage controlled oscillator used to modulate the digital data using FSK modulation technique.

3.3.2.8 PLL

3.3.2.9 Timer 555

3.4 System design steps

3.4.1 Step one: Generation of FSK signal

Signal has to be modulated before transmission, and one of the methods is the frequency-

shift keying (FSK) modulation. FSK technique is to modulate the data signal to two different

frequencies to achieve effective transmission. At the receiver, the data signal will be recovered

based on the two different frequencies of the received signal.

Figure 3.10 shows the relationship between the FSK signal and the data signal.

Figure 3.9: VCO LM566


36

The technique of FSK is widely used in commercial and industrial wire transmission and

wireless transmission.

For wire transmission such as telephone, the frequencies are as follow:

Space = 1370 Hz, Mark = 870 Hz Or Space = 2225 Hz, Mark = 2025 Hz

We obtained the FSK signal by using three methods. The first and the simplest way is to

use multiplexer. The second method by using 555 timer. Finally, we have used LM565 voltage

controlled oscillator to get the required signal with the specified frequency.[11]

3.4.1.1 Design 1: Using Multiplexer

Two function generators are used. They produce two signals with different frequencies

(mark and space frequencies). Each generator is connected to one of the multiplexer inputs. The

digital data is connected as selecting signal.

This experiment was done in proteus simulation. Figure 3.11 illustrate the simulation

components. Which consist of a multiplexor and two function generators.

Figure 3.10: FSK signal and data signal


37

3.4.1.2 Design 2: Using 555 timer

The output frequency of the signal was based on the input digital signal given to the base

of the transistor. When the given input was high that is of logic 1 the PNP transistor was Q is off

and IC 555 timer works in the normal mode of operation giving out the series of square wave

pulses thus there will be no change in the frequency of the output signal. Here the resistors Ra, Rb

and Capacitor C was selected in such a way to obtain output frequency. The output frequency

when the input was high was given by the equation:

Equation 1

𝑓 =1.45

𝑅𝑎 + 2𝑅𝑏

When the input binary data if logic 0, the PNP transistor is on and its connects the resistance

Rc across resistance Ra. The resistors Rc is selected in such a way that the value of 1space

frequency. Here the value of Rc added in addition to the Ra, Rb and C to contribute the working

Figure 3.11: Multiplexor circuit


38

of the NE555.This makes the charging and discharging quicker resulting in high frequency waves

as output. The Ra, Rb, Rc and C values was selected in such a way to obtain output of space

frequency. This was given by the equation:

Equation 2

𝑓 =1.45

((𝑅𝑎||𝑅𝑐) + 2𝑅𝑏)𝐶

Figure (3.12) shows the simulation of the circuit using proteus 8.6.

After simulation step actual circuit implementation was done as shown in figure (3.13).

Figure 3.12: 555 timer simulation


39

3.4.1.3 Design three: using Voltage Controlled oscillator (VCO) LM566

The two frequencies can be produced by using a Voltage Controlled Oscillator (VCO). The

output signal frequencies are varied by the difference levels of the input pulse to produce two

different frequencies. Each output signal frequency corresponds to an input voltage level (i.e. "0"

or "1").

The oscillation frequency of LM566 is:

Equation 3

𝑓0 =2

𝑅10𝐶5(𝑉𝐶𝐶 − 𝑉𝐼𝑁

𝑉𝐶𝐶)

Figure 3.13: Real Circuit


40

Where Vcc is the power supply voltage input at pin 8 of LM566. Vin is the input voltage

of LM566 at pin 5.

The simulation for our circuit is illustrated at figure (3.14). First we have to convert the

voltage level of data signal to appropriate voltage level that will be the LM566 input. According

to the input voltage level the VCO will produce the frequency.

In this circuit, Q2 will operate as NOT gate. When the input signal of the base of Q2 is

high, then Q2 will switch on. At this moment, the output signal of the collector will be low (around

0.2 V), so Q1 will switch off. When input signal of the base of Q2 is low (0 V), Q2 will switch

off. At this moment, the output signal of the collector of Q2 is high (5 V), so, Q1 will switch on.

When Q1 switch off, the input voltage of VCO is:

Equation 4

𝑉1 = (𝑅2

𝑅2 − 𝑅3)𝑉𝐶𝐶

The VCO output signal frequency is f1. When Q1 switch on, the input voltage of VCO is

(Assume the resistance of Q1 is only a few ohm)

Equation 5

𝑉2 = (𝑅1//𝑅2

(𝑅1//𝑅2) + 𝑅3)𝑉𝐶𝐶

At this moment, the output signal frequency of VCO is f2. So, we just need to adjust R1

and R2, then the output signal frequencies of VCO will become f1 and f2 which are 1370 Hz and

870 Hz, respectively. In figure (3.14), the two amplifier, R1, R4, R5, R6, R8, R10, C1, C3, C5 and

C6 comprise a 4th order low-pass filter. The objective is to remove the unwanted signal from the

LM566 VCO output (TP2), so that we can obtain the sinusoidal waveform signal.[11]

Figure (3.14) shows the simulation of the modulation circuit using LM566 FSK generator.

Figure (3.15) shows the actual circuit implementation.


41

The mapping of the resistors from the equations to the simulation:

R1 from equations: R12 in the simulation.



Figure 3.14: LM566 circuit simulation.


42

3.4.2 Step two: Demodulation

3.4.2.1 Using Phase Locked Loop

Generally, phase locked loop (PLL) can be divided into 3 main parts, which are the phase

detector (PD), loop filter (LF) and voltage controlled oscillator (VCO). The block diagram of PLL

is shown in figure 3.16.

Figure 3.15: LM566 circuit implementation


43

In figure 3.17, when the input signal frequency changes, the output signal of the phase

detector will change and so as well as the output voltage.

when the input signal frequency changes, the output signal of the phase detector will

change and so as well as the output voltage. We can use this characteristic to design the FSK

demodulator. Let the FSK signal frequencies as f1 and f2, then these signals are inputted to the

input terminal of figure 3.16. When the input signal frequency is f1, the output voltage will be V1.

When the input signal frequency is f2, the output voltage is V2. At this moment, we have converted

the frequency to voltage. If we add a comparator at the output terminal of PLL, the reference

voltage will lie between V1 and V2, then at the output terminal of comparator, we are able to

obtain the digital signal, which is the demodulated FSK signal.[12]

Phase

Detector

VCO

Loop filter Amp.

Figure 3.17: Phase Locked Loop components

Figure 3.18: 4046 PLL simulation


44

Pin 1 is connected to negative voltage supply, -5 V. Pins 2 and 3 are connected to the input

signals, but normally pin 3 will connect to ground. If pins 4 and 5 are connected to frequency

multiplier, then various multiplications of frequencies can be obtained. In this experiment, we need

not use the frequency multiplier; therefore, these two pins are shorted. Pin 6 is the reference voltage

output. The internal resistor (Rx) of pin 7 and the external capacitor (C3) comprise a loop filter.

Pin 8 is connected to timing resistor (VR1). Pin 9 is connected to timing capacitor (C2). Pin 10 the

positive voltage supply +5 V of LM565.

In the design of the PLL three concepts must be taken into consideration:

1) The Free-Running Frequency of LM565:

When LM565 without any input signal, the output signal of VCO is called free-running

frequency. The C2 is timing capacitor and the variable resistor VR1 is timing resistor. The

free-running frequency (fo) of VCO of the LM565 is determined by C2 and VR1. The

expression is:

Equation 6

𝑓𝑜 =1.2

4𝑉𝑅1𝐶2

2) The locked Range of LM565:

When the PLL is in locked condition, if the frequency of the input signal (fi) deviates from

fo, then the PLL will remain in the locked condition. When fi reaches a certain frequency,

which the PLL is not able to lock, then the difference between fi and fo is called the locked

range. The locked range of LM565 can be expressed as:

Equation 7

𝑓𝐿 =8𝑓𝑜

𝑉𝐶=

8𝑓𝑜

𝑉𝐶𝐶 − 𝑉𝐸𝐸

3) The Capture Range of LM565


45

The initial mode of PLL is in unlocked condition, then the frequency of the input signal

(fi) will come near to fo. When fi reaches a certain frequency, the PLL will be in locked

condition. At this moment, the difference between fi and fo is called the capture range. The

captured range of LM565 can be expressed as:

Equation 8

𝑓𝐶 =1

2√

2𝜋 × 𝑓𝐿

3.6 × 108 × 𝐶2

[12]

3.4.3 Step three: coupling circuit

The coupler is the heart of the PLC system. The connection between the power line and

the modulation and demodulation circuits is done using line trap and line coupler.

In our coupling circuit a double LC bandpass filter is used to provide efficient rejection

50Hz signal (high pass) and anti-aliasing (low pass) for digital filter without any adjustment or

tunable from the components. A unidirectional transient suppressor (SA5.0A, D1) is connected to

protect from overvoltage. It also protects the transmitter from negative transient voltage which also

might damage the circuit output amplifier

Figure 3.19: coupling circuit simulation.


46

Principle of superposition can be used in coupling circuit analysis. Assuming the 240Vrms,

50Hz AC sine wave as a signal source a. Thevenin Equivalent Output circuit can be calculated as

follows:

Equation 9

𝑉𝐶𝑂 = 𝑉𝐼𝑁(𝑍2

𝑍1 − 𝑍2)

Where: 𝑍1 = 𝑋𝐶1 + 𝑋𝐿1 and 𝑍2 = 𝑋𝐶3||𝑋𝐿2

𝜔 = 2𝜋𝑓 = 2 × 3.1416 × 50 = 314.16

𝑋𝐶1 =1

𝜔×𝐶1=

1

314.159×47×10−9 = 67725.51

𝑋𝐶1 = 𝑋𝐶3 = 67725.51

𝑋𝐿1 = 𝜔 × 𝐿1 = 2 × 3.1416 × 50 × 47 × 10−6 = 0.014756

𝑍1 = −𝑗67725.51 + 𝑗0.014765 = −𝑗67725.49

𝑍2 =−𝑗67725.51×𝑗0.014765

−𝑗67725.51+𝑗0.014765=

(67725.51∠−90)(0.014765∠90)

−𝑗67725.495

=9999.967∠0

−𝑗67725.495=

999.967∠0

67725.495∠−90

= 0.014765∠90 = 𝑗0.014765

𝑉𝑂𝐶 = 240∠90 (0.014765∠90

−𝑗67725.49+𝑗0.14765)

= 240∠90 (0.014765∠90

67725.49∠−90)

= 240∠90 (2.18 × 10−7∠180)

= 52 × 10−6∠270

This ratio will effectively eliminate the 230VRMS signal to 52 uV with attenuation of

133.28dB.

Connection of the coupling circuit to the transmitter circuit and receiver circuit is shown

in figure (3-19), figure (3-20) respectively.


47

Figure 3.20: modulation circuit connected to coupling circuit.

Figure 3.21: demodulation circuit connected to coupling circuit.

CHAPTER FOUR RESULT AND DISCUSSION

48

4 CHAPTER FOUR:

RESULT AND DISCUSSION

4.1 Overview

This chapter is continuity to the methodology and design chapter, which describes the

implementation steps, testing, measuring and results.

Some calculations are made to obtain the required values of the components in the

modulation, demodulation, filters and coupling circuits.

Results are displayed in form of tables and figures.

4.2 Calculations

4.2.1 FSK modulation

4.2.1.1 For timer circuit

Using equations (1) and (2) to obtain the required frequencies:

Mark frequency=870

𝑓 =1.45

𝑅𝑎 + 2𝑅𝑏

𝑅𝑎 = 52𝑘

𝑅𝑏 = 58𝑘

Space frequency=1370

𝑓 =1.45

((𝑅𝑎||𝑅𝑐) + 2𝑅𝑏)𝐶

𝑅𝑐 = 50𝑘

𝐶 = 10𝑛𝑓

Figures (4.1) and figure (4.2) show the last 555 circuit components values and the

simulation result.


49

Figure 4.2: timer circuit with prober values

Figure 4.1: timer circuit output


50

4.2.1.2 For VCO circuit

The components values were measured to obtain frequency of 870 Hz and 1370 Hz. Using

formulas (3), (4) and (5) in chapter 3.

𝑓0 =2

𝑅10𝐶5(𝑉𝐶𝐶 − 𝑉𝐼𝑁

𝑉𝐶𝐶)

To obtain the value of VR2:

After substitute:

fo = 1370, VCC = 12, R10 = 5.6 k, C5 = 0.1 u

We find that VIN = 7.3968 = V1.

After using equation:

𝑉1 = (𝑉𝑅2

𝑉𝑅2 − 𝑅6)𝑉𝐶𝐶

VR2 = 3.105 kΩ

To obtain the value of VR1:

fo = 870, VCC = 12, R10 = 5.6 k, C5 = 0.1 u, VR2 = 3.105,

we find that VIN = 9.0768 = V2

Figure 4.3: real circuit result


51

after using equation:

𝑉2 = (𝑉𝑅1//𝑉𝑅2

(𝑉𝑅1//𝑉𝑅2) + 𝑅6)𝑉𝐶𝐶

VR1 = 3.33 kΩ

Figure (4.5) shows the final modulation circuit simulation with the calculated values.

Figure (4.4) shows the output from the modulation circuit with LM566 chip.

Figure 4.5: VCO final circuit simulation

Figure 4.4: FSK modulation output


52

4.2.2 Demodulation using PLL:

For 4046 chip there are different equations to find the values of capture range and locked range[13].

Equation 10

𝑓𝑚𝑖𝑛 = 1

𝑅2 × (𝐶15 + 32𝑝𝐹)

Equation 11

𝑓𝑚𝑎𝑥 = 𝑓𝑚𝑖𝑛 +1

𝑅1 × (𝐶15 + 32𝑝𝐹)

Where R2 the resistor connected to pin 12 in the 4046 chip, R1 the resistor connected to the

11th pin in the 4046 chip.

To obtain the capture range of 0Hz to 5kHz the value of R2 must equal infinity, so the 12th

pin is an open circuit. R1 supposed to be 300kΩ, then C15 after calculations will equal 360 pF.

Figure 4.6: transceiver circuit


53

Figure (4.6) shows the overall circuit simulation: transmitter and receiver circuits. Figure

(4.7) shows the transmitted data and result of the modulated signal and the signal after the

demodulation.


Figure is the simulation result for the coupling circuit

Parameter values was calculated to give the wanted results.

Figure 4.7: overall transceiver circuit results


54

Table 4-1: coupling circuit parameters

Parameter value

L1 47u

L2 47u

C1 10n

C2 1u

C3 47u

C4 47n

4.3 Discussion

4.3.1 Modulation

In the first design step which was generating FSK signal three designs were tested.

Multiplexer design Was The simplest one but it's simulation results was not satisfying as

shown in figure (4.9). FSK signal was not always obtained, only in certain values of data

Figure 4.8: coupling circuit result


55

frequency. To obtain good results space and mark frequencies must not be separated by a large

range of frequency from the frequency of the transmitted data. Thus this choice was eliminated.

Figure 4.10: Mux bad result

Figure 4.9: Mux good result


56

Other two designs were tested. They gave good results at required modulation frequencies

for any data frequency as shown in figures (4.1) (4.4)

As seen in the result of the 555 timer real circuit the signal is distorted with square wave.

The interference occurred because of the not accurate components values.

The VCO design was our last Choice because there is no need for function generator

(smaller circuit).

Firstly, we have chosen XR-2206 chip to be the modulated chip according to its simple

circuit and design. But it has no simulation model in proteus or other simulators. Also it is not

available in the market. So we alternate it with LM566.

In LM566 circuit the output frequencies are less than the calculated frequencies by

approximately 200 Hz. In much high frequencies it does not effect.

From the frequency equation in chapter 3, the output frequency is affected by the values of

VR1 and VR2 for each values of R10 and C5. In high frequencies the values of R10 and C5 must be

calculated to obtain the required frequency values.

The real circuit output was not perfect as simulation. The output picture was not included

because we couldn’t capture a good result.

4.3.2 Demodulation

Capture range was chosen to be from zero to 5kHz to ensure that our transmitted data will

pass through the 4046 demodulator. As we know that the coupling circuit will block the 50 or 60

Hz power signal.

The components that are connected to 4046 chip must be calculated carefully within the

specified range to ensure that the demodulation would be perfectly done.

A delay between the digital transmitted data and the demodulated signal because of the

filters and components that the signal pass through. In real implementation of the circuit the delay

will increase according to the effect of power lines and the trap circuits.

4.3.3 Coupling

The designed circuit blocks the 240v 50hz signal from modem circuit as shown in figure

(4.8) and permit the modulated signal to be injected into the power line. usually coupling circuit


57

is more complicated here we used the simplest circuit that can protect our circuit and make the

propagation of the signal through power line possible.

CHAPTER FIVE CONCLUSION AND RECOMMINDATIONS

58

5 CHAPTER FIVE:

CONCLUSION AND RECOMINDATIONS

5.1 Conclusion

According to the high noise in the power lines, recovery of a transmitted data is difficult.

So many circuits should be designed to ensure successful data transmission and reception between

two nodes. In this project the transmitter and receiver circuits were successfully designed. The

implementation of the transmitter was done by using three testes in different three circuits using

different three chips. Lastly the perfect transmitter and receiver circuits design are implemented

by using LM566 chip and 4046 chip respectively.

In this project FSK modulation technique was used because it’s simple and easy to

implement. The representation of logic 0 and logic 1 with two different frequencies makes the

recovery of the digital data even if one of the frequencies have been attenuated.

A coupling circuit with filters and isolation transformer was designed and tested in the

simulator to ensure full protection to the transceiver circuit from the high voltage by blocking the

50Hz electricity signal.

This project cost less because of the availability of equipments and there is no need to

establish a new network since it is already existing for electrical power distribution purpose. This

makes the electrical network has the ability of data transmission and receiving in addition to the

main distribution function.

5.2 Problems and solutions

For modulation circuit, XR-2206 chip has been chosen to be the FSK modulation

chip. But I didn’t found it so another circuit with LM566 chip was designed.

The first demodulation design was by using NE565 chip. I found that there is no

model for it in the simulator, so I substitute it with 4046 chip.

Power line communication has no universal standards or technology.

CHAPTER FIVE CONCLUSION AND RECOMMINDATIONS

59

The full system that consist of the transceiver, coupling circuits and the power lines

could not be simulated. There is no one simulation can manipulate all these

components.

5.3 Future works

Full PLC system design would be implemented so it could be used in reality to transmit

data in many applications such as home automation, automatic meter reading and broadband over

power lines.

60

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design of power line communication system by

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