Remote Detection of Illegal Electricity Usage

A SOLUTION TO REMOTE DETECTION OF ILLEGAL

ELECTRICITY USAGE VIA POWER LINE

COMMUNICATION

SEMINAR REPORT

Submitted in partial fulfillment of the

requirements for the award of B.Tech Degree in

Electrical & Electronics Engineering

ACKNOWLEDGEMENT

I have great pleasure to express my gratitude and obligations to Smt X,

Assistant Professor, Department of Electrical & Electronics Engineering, College of

Engineering, for her valuable guidance, constant encouragement and creative

suggestions to make this seminar a great success.

I express my sincere thanks to Mr. Y Assistant Professor and Head of the

Department, Department of Electrical & Electronics Engineering, College of Engineering,

for his encouragement and support.

I express my thanks to Dr. Z , Principal, College Of Engineering,

, for all necessary help extended to me in the fulfillment of this seminar.

I also express my sincere gratitude to all the Staff Members of Department of

Electrical & Electronics Engineering, College of Engineering, for their valuable

help and encouragement, which lead to the successful accomplishment of this seminar.

I am also thankful to my friends for their valuable suggestions and encouragements. Above all I thank the ALMIGHTY, without whose blessing I would ever be able to

complete my work.

ABSTRACT

Power line communication (PLC) presents an interesting and economical solution for

Automatic Meter Reading (AMR). If an AMR system via PLC is set in a power delivery

system, a detection system for illegal electricity usage may be easily added in the existing

PLC network. In the detection system, the second digitally energy meter chip is used and the

value of energy is stored. The recorded energy is compared with the value at the main kilo

Watt-hour meter. In the case of the difference between two recorded energy data, an error

signal is generated and transmitted via PLC network. The detector and control system is

proposed. The architecture of the system and their critical components are given. The

measurement results are given.

Power line communication (PLC) is of great interest concerning home automation.

Generally homes and buildings automation is realized through systems which need a special

transmission medium such as pair of twisted wire, coaxial cables or optical fibers. Recent

technological developments led to power line medium equipments which send and receive

information with some reliability. The main advantage of a PLC system is that the physical

medium is already installed, making it an attractive alternative in all buildings without

prerouted data infrastructure, like historical buildings. The development of power line

communication system requires detailed knowledge of the channel properties, such as

transfer function, interference scenario and channel capacity in order to choose suitable

transmission methods. This paper deals with the typical channel properties like access

impedance, noise scenario and modeling approach for the designing of PLC system.

Eventually an evaluation of different modulation schemes is carried to optimize PLC system

design.

This report describes detector system for illegal electricity usage using the power lines

based on the research work-taking place at the Central Power Research Institute (CPRI),

Bangalore. The target of this study is to discover new and possible solutions for this problem.

CONTENTS

Chapter Title Page no

1. INTRODUCTION 01

2. DETECTION OF ILLEGAL ELECTRICITY USAGE 02

2.1 METHODS OF ILLEGAL ELECTRICITY USAGE 02

2.2 BUILDING BLOCKS FOR DETECTION 02

2.3 POWER LINE COMMUNICATION (PLC) 07

2.4 CHANNEL CHARACTERISTICS 09

2.5 POWER LINE CHANNEL CHARACTERISTICS 10

2.6 MODULATION SCHEMES FOR PLC SYSTEM DESIGN 12

2.7 ADVANTAGES AND DISADVANTAGES OF POWER LINE 13

3. DETECTION AND CONTROL SYSTEM 15

3.1 SIMULATION 17

4. OVER VIEW OF THE PROPOSED DETECTOR SYSTEM 19

5. CONCLUSION 21

REFERENCES 22

Seminar Report 2013 A Solution to Remote Detection of Illegal Electricity Usage via PLC

CHAPTER 1

INTRODUCTION

India, the largest democracy with an estimated population of about 1.04 billion, is on

a road to rapid growth in economy. Energy, particularly electricity, is a key input for

accelerating economic growth. The theft of electricity is a criminal offence and power

utilities are losing billions of rupees in this account. If an Automatic Meter Reading system

via Power line Communication is set in a power delivery system, a detection system for

illegal electricity usage is possible .Power line communications (PLC) has many new service

possibilities on the data transferring via power lines without use of extra cables. Automatic

Meter Reading (AMR) is a very important application in these possibilities due to every user

connected each other via modems, using power lines. AMR is a technique to facilitate remote

readings of energy consumption.

Power line communication (PLC) is of great interest concerning home automation.

Generally homes and buildings automation is realized through systems which need a special

transmission medium such as pair of twisted wire, coaxial cables or optical fibers. Recent

technological developments led to power line medium equipments which send and receive

information with some reliability. The main advantage of a PLC system is that the physical

medium is already installed, making it an attractive alternative in all buildings without

prerouted data infrastructure, like historical buildings. The development of power line

communication system requires detailed knowledge of the channel properties, such as

transfer function, interference scenario and channel capacity in order to choose suitable

transmission methods. This paper deals with the typical channel properties like access

impedance, noise scenario and modelling approach for the designing of PLC system.

Eventually an evaluation of different modulation schemes is carried to optimize PLC system

design.

The following sections will describe the proposed detection and control system for

illegal electricity usage using the power lines. The scheme is based on the research work-

taking place at “Central Power Research Unit (CPRI), Bangalore ”.In this section the

discussion is on how a subscriber can illegally use the electricity and the basic building

blocks for the detection using power line communication.

Dept. of Electrical & Electronics Engg Page 1


CHAPTER 2

DETECTION OF ILLEGAL ELECTRICITY USAGE

In this section the discussion is on how a subscriber can illegally use the electricity

and the basic building blocks for the detection using power line communication.

2.1 Methods of illegal electricity usage

In illegal usage a subscriber illegally use electricity in the following ways,

1) Using the mechanical objects:

A subscriber can use some mechanical objects to prevent the revolution of a meter, so

that disk speed is reduced and the recorded energy is also reduced.

2) Using a fixed magnet:

A subscriber can use a fixed magnet to change the electromagnetic field of the current

coils. As is well known, the recorded energy is proportional to electromagnetic field.

3) Using the external phase before meter terminals:

This method gives subscribers free energy without any record.

4) Switching the energy cables at the meter

connector box:

In this way, the current does not pass through the current coil of the meter, so the

meter does not record the energy consumption.

Although all of the methods explained above may be valid for electromechanical

meters, only the last two methods are valid for digital meters. Therefore, this problem should

be solved by electronics and control techniques.

2.2 Building blocks for detection:

Automatic Meter Reading (AMR): The AMR system starts at the meter. Some

means of translating readings from rotating meter dials, or cyclometer style meter dials, into

digital form is necessary in order to send digital metering data from the customer site to a

central point.

Dept. of Electrical & Electronics Engg. Page 2


Fig 2: Electromechanical movement to digital signal conversion.

In most cases, the meter that is used in an AMR system is the same ordinary meter

used for manual reading but the difference with conventional energy meter is the addition of

some device to generate pulses relating to the amount of consumption monitored, or

generates an electronic, digital code that translates to the actual reading on the meter dials.

One such technique using optical sensor is shown in above fig……

Three main components of AMR system are:

1. Meter interface module with power supply, meter sensors, controlling electronics and a

communication interface that allows data to be transmitted from this remote device to a

central location. In many instances, this communication interface is bi-directional and allows

central office signals to be received by the remote unit as well. Every electric, gas or water

meter must have such an interface unit to be remotely read. Some key components of the

remote device may be shared by more than one meter without regard for the type of meter;

i.e.., electric, gas or water.

2. Communications systems used for the transmission, or telemetry, of data and control send

signals between the meter interface units and the central office. Typically, such

communications take the form of telephone, power line carrier (plc), radio frequency (RF), or

cable television. The system components in the communications system depend on the

communication media used

3. Central office systems equipment including modems, receivers, data concentrators,

controllers, host upload links, and host computer. Many utilities have for some time been

taking advantage of electronic meter reading systems using handheld data terminals that



communicate with a central controller via phone lines. There is great similarity between the

host side electronic meter reading and automatic meter reading system function.

Fig 2.1 AMR communication setup

There are three major building block functions that the meter interface and related

electronics must perform. These are common to electric, gas and water Implementations.

First, an electromechanical or electro-optical interface must be incorporated into or attached

to the meter. This converts information conveyed by the meter's mechanical register indexes,

or dial readings, into electronic signals which may be processed, manipulated, stored and

transmitted. The second functional building block is a controller unit consisting of a low-

voltage power supply, signal processing electronics, microcomputer, random access memory

and program memory used to store the real-time run or operating system program. The

controller unit is used to process the signals originating from the meter's electromechanical or

electro-optical interface device. In effect, the controller unit converts the meter's

electromechanical interface device signals into computer type electronic digital

representations of the meters exact index or dial readings-much as a calculator converts

keypad entries into numbers appearing on the display. The controller's RAM memory

maintains an up-to-the-minute mirror image of the meter's dials and as the dials increment, so

do the numerical representations stored in RAM.

The third functional building block is the communication scheme and its associated

transmit/receive electronics. Generally, meter-to-utility host communications use one or more

transmission techniques: telephone, power line carrier, radio frequency through the airwaves,

or television cable. There are many sub-categories of each of these communication forms

having to do with data flow, modulation techniques, distance from remote site to central

station and data transmission rates. The AMR system starts at the meter. Some means of

translating readings from rotating meter dials, or cyclometer style meter dials, into digital

form is necessary in order to send digital metering data from the customer site to a central

point. In most cases, the meter that is used in an AMR System is the same ordinary meter

used for manual reading. The internal mechanism used for metering consumption is identical



in both cases. The one difference is the addition of some device to generate pulses relating to

the amount of consumption monitored, or generate an electronic, digital code that translates

to the actual reading on the meter dials.

The four communication methods used for meter reading have various strengths and

weaknesses.

Telephone lines -Telephone lines are desirable from an economic point of view since most

electricity users in the country have telephone service. The telephone system provides an

ideal communication infrastructure for AMR systems due to simplicity of operation, quality

of data, high noise immunity, reliability and low cost, both at the remote site and the central

station. Telephone communications AMR systems are categorized by the method of call

initiation and initial data flow. The two most common forms are inbound communications

and outbound communications. With inbound communications, a unit at the customer site

(usually the controller or a modem connected to the controller) dials in to the central station

system at the utility without first receiving an interrogation message. The remote site unit

initiates the communication at a date and time programmed into the controller's memory. In

the case of tampering or system malfunctions, a call can be initiated to the utility's central

station, where the alarm condition will be received and processed. This approach takes

advantage of the fixed monthly charge for local calls that the customer is already paying. No

additional telephone access equipment is required. The disadvantages of inbound

communications are that the utility cannot obtain real-time data upon request, nor can the

utility reprogram the controller unit or issue control commands as in the case of connect-

disconnect or energy management, should these capabilities be incorporated into the system.

Outbound communications arc those where data communications are initiated by a central

unit located at the utility or at a local telephone company switching station. These systems

respond to a query and require central telephone switching equipment and test trunk lines.

Telephone company involvement is required to enable the utility's central station computer to

dial out to a customer's remote unit without ringing the customer's telephone. The advantage

of this approach is that these systems function in real time, as needed, which simplifies the

implementation of demand load recording surveys, status monitoring, etc. The primary

disadvantages to an outbound communications approach are the capital costs associated with

the telephone company's involvement and the recurring tariffs that telephone companies

charge. An additional complication arises in geographical areas served by one electric utility

and two or more telephone companies. A third approach is termed bidirectional

communications. In this case, communications are initiated from the remote site or the



utility's central station. The advantages of both inbound and outbound communications are

incorporated in this system design. In the majority of cases, the inbound function is used,

thereby reducing telephone charges. Also, due to the decreased density of outbound traffic,

telephone company switchgear and test trunk lines are minimized.

Power line carrier -Power line carrier communications take place over the same lines that

deliver electricity. This technique involves injecting a high frequency AC carrier onto the

power line and modulating this carrier with data originating from the remote meter or central

station. Years of research, however, have not overcome the technical problems that preclude

this medium from being a cost effective solution over primary transmission lines. Power line

carrier techniques may be used successfully and cost effectively for short distances; i.e., from

a customer’s meter to a pole or surface mounted transformer. It is very expensive to pass this

data through a distribution transformer and onto the primary distribution lines and the

resulting communications is slow due to the narrow bandwidth and mono-directional

meaning data is transmitted from the meter to the utility but the utility cannot send data or

control signals back to the meter or associated devices at the subscriber side.

Radio frequency -Radio frequency, or RF, systems make use of small low power RF

transmitters or transceivers located at the controller. These may take advantage of licensed or

unlicensed portions of the RF spectrum and the effective radiated power of the transmitter

and the distances capable of being traversed will vary as a function of the frequency and

power of the remote transmitters and the receiving strategies employed. A variety of system

configurations have been field tested thus far. The most successful employs a mobile unit

operated in a van that sends a wakeup and transmit command to the remote meter units in its

range. The remote meter units pick up the signal and respond by sending back requested data

to the van's computer for later uploading and billing. This system is commercially available

for use with gas meters. A variation of this approach employs remote meter units that

regularly transmit every few seconds and a small portable receiver connected to a hand-held

data terminal. Two of the more exotic approaches (in 1992) involve use of a cellular

telephone network system and satellite communications.

The mobile receiver approach suffers the significant disadvantage of being effectively

mono-directional; thus, communication cannot be initiated from the utility's central office.

Therefore, systems of this type have limited function and relatively low feature/function cost

ratios and are not well suited for use by electric utilities.

Cable television communication -This communication approach uses existing cable

television lines to transmit data. Some tests have shown that this may be a cumbersome and



expensive approach but some municipal utilities that own cable systems are undertaking this

type of communication. Additionally, many installed cable systems are not configured to pass

signals from the subscriber's site to a central facility. It is expensive to upgrade these systems

with wide-band bidirectional amplifiers and subscriber interactive taps. Cable television

should not be discounted, however, as a viable communications medium. Several municipal

electric utilities have purchased their local cable companies and upgraded systems consistent

with the needs of AMR. If these utilities sell AMR services to local gas and water utilities,

this approach can prove very viable. Future advances in cable will include bi-directional

digital signal transmission and much wider band width ultimately using fiber optics at which

point cable will be an ideal communications medium. The full-scale implementation of AMR

requires that a data communication network be established that effectively links every utility

customer with the utility's central office. The actual amount of AMR related data and its

frequency of transmission is very low. These factors contribute to the difficulties encountered

in the economic justification of AMR systems. There are, however, a myriad of services and

functions that can be accomplished through this communication system, some of which

significantly reduce a utility's operating costs and some of which can actually generate

additional revenues. The incremental cost associated with incorporating these functions in the

AMR system controllers is marginal. Payback can vary enormously. In theory, it is almost

possible to finance a full-scale AMR system installation through the resulting costs savings

and new revenue-producing services

2.3 Power line communication (PLC):

Power line carrier communications take place over the same lines that deliver

electricity. This technique involves injecting a high frequency AC carrier onto the power line

and modulating this carrier with data originating from the remote meter or central station.

Power line communications has many new service possibilities on the data transferring via

power lines without use of extra cables. AMR is a very important application in these

possibilities due to every user connected each other via power lines. In this power network,

every user connected to each other via modems with data originating from the remote meter

or central station.

Electrical power systems vary in configuration from country to country depending on

the state of the respective power sources and loads. The practice of using medium-voltage

(11-to-33kV) and low-voltage (100-to-400V) power distribution lines as high-speed PLC



communication means and optical networks as backbone networks is commonplace. Under

normal service conditions, they can be broadly divided into open-loop systems, each with a

single opening, and tree systems with radial arranged lines. In the case of tree systems,

connection points for adjacent systems are provided in order that paths/loads may be

switched when necessary for operation. Additionally, in terms of distribution line types, there

are underground cables and overhead power distribution lines. Where transformers are

concerned, they can be divided into pole-mounted transformers, pad-mounted transformers

and indoor transformers.

High-speed PLC applications of the future include Automatic Meter Reading (AMR),

power system fault detection, power theft detection, leakage current detection, and the

measurement/control/energy-management of electrical power equipment for electrical power

companies, as well as home security, the remote- monitoring/control of electrical household

appliances, online games, home networks, and billing.

Technology development caused a real revolution inside the electric power

distribution industry. The Significant news came from the solution known as power line

communication (PLC) or broadband over power line communication (BPL) as solution for

data transmission transported by the electric grid. The advantages of PLC are obvious as no

additional wires are required because of the power lines being available in almost every

room. Each wall plug and each installation socket provides an access point to the power line

network.

However the power line is not at all an ideal communication channel. Large number

of experimental results shows that the low voltage distribution networks abounds with all

kinds of noises including background noise, narrowband noise and impulse noise and

attenuation of the transmitted signal is also the key impartment . Further, due to the fact that

the structure of the power distribution network is far from matching requirements, reflection

exists at some nodes in the network. This result a multipath effects. Therefore it is a real

challenge to realize data transmission over low voltage distribution network.

Power line carrier communications take place over the same lines that deliver

electricity. This technique involves injecting a high frequency AC carrier onto the power line

and modulating this carrier with data originating from the remote meter or central station.

Years of research, however, have not overcome the technical problems that preclude this

medium from being a cost effective solution over primary transmission lines. Power line



carrier techniques may be used successfully and cost effectively for short distances; i.e., from

a customer’s meter to a pole or surface mounted transformer. It is very expensive to pass this

data through a distribution transformer and onto the primary distribution lines and the

resulting communications is slow due to the narrow bandwidth and mono-directional

meaning data is transmitted from the meter to the utility but the utility cannot send data or

control signals back to the meter or associated devices at the subscriber side.

2.4 CHANNEL CHARACTERISTICS

Power lines constitute a rather hostile medium for data transmission. Varying

impedance, considerable noise and high attenuation are the main issues. The channel mixes

the nasty behaviour of a power line with that of a communication channel. The transmission

environment for PLC seems much worse than that for mobile communications, so we need to

not only utilize existing advanced technologies, but also create novel ones. Channel

characteristics can be both time and frequency dependent, and also dependent on the location

of transmitter and receiver in the specific power line infrastructure. Hence, the channel in

general is described as random time varying with a frequency-depended signal to noise ratio

(SNR) over the communication bandwidth.

Impedance is highly varying with frequency and ranges between a few ohms and a

few kilo ohms with peaks at some frequencies where the network behaves like a parallel

resonant circuit. In most frequency ranges the impedance shows inductive or capacitive

behaviour around 90Ω to 100Ω. The net impedance is strongly influenced by the network

topology and connected loads, so we can say that the low voltage mains do not have

essentially characteristics impedance since loads being switched on and off randomly

introduce a change in impedance.

Communication signals at low frequency are propagated along the low voltage power

line through conducted emission with very little energy radiated from the line causing

interference to other communication services. Different noise sources, motors, radio signals

and power supplies result in a noise curve very much dependent on location and time.

Generally channel noise varies strongly with frequency, load, and time of day and

geographical location. The noise spectrum in frequency range up to 145 kHz



2.5 POWER LINE CHANNEL CHARACTERISTICS

[a].Disturbances

Sources of channel disturbances are different in the three voltage networks. Lightning,

circuit breaker operations and the transient produced within a power during the high activity

time, more switching-on and switching-off of the loads occur. Throughout the whole

frequency band of interest, the standard deviation during the high activity time is higher by

about 10dBm. Analysis of the measured spectra reveals that four types of disturbances,

besides the omnipresent background noise, are present in the power line, either occurring

alone or together.

Fig. 2.2 Mean Noise Level in a Flat of a HDB Block

Fig.2.3 Standard Deviation of Noise Level in a Flat of a HDB Block



(i).Disturbance with a Smooth Spectrum

This type of disturbance is broadband in nature. The main source of this disturbance is small

motors with serial windings found in many household appliances.

(ii).Disturbance with Frequencies Synchronous to Power System Frequency

The main culprit of such disturbance is the silicon controlled rectifier (SCR) which switches

certain amount of times every 50Hz cycle. An example of an appliance containing a SCR is

the light dimmer. Remote controller boards (RCB) at the kWh meters of the same phase. Fig.

4 shows the main idea for the proposed system for the red phase

(iii).Single Event Impulse Disturbance

This type of disturbance is caused by all kinds of switching operations, such as the switching

phenomenon of thermostats. This disturbance affects the whole range of frequency band and

its duration is very short.

(iv).Narrow-band Disturbance

The narrow-band disturbance is periodic and non synchronous to the power system

frequency. It is usually generated by television sets and computer monitors. The repetition of

pulses depends on the screen scanning that varies among the television and computer monitor

standards. Switch mode power supplies also cause such disturbance.

[b].Signal Attenuation

(i).Coupling Loss

The signal experiences losses due to coupling circuits, both coupling-in and coupling-

out. Such loss is inevitable because direct injection of signals into the power lines is

impossible without isolation.

(ii).Branching Loss

There are losses due to the branching of circuits. In the case of transmission lines,

when a signal comes across a discontinuity, part of it gets transmitted and the other part gets

reflected. Branching causes discontinuities in the power lines. Reflection is undesirable as it

causes signal loss and often leads to echoing.

(iii).Line Loss

The power line has some impedance and its impedance depends on its size and length.

So, part of the signal loss will be due to the power lines. Of these three losses, coupling loss

can be reduced through better-designed coupling circuits. Line and branching losses are more

severe and are also very difficult to reduce. It is found that the severity of signal attenuation

generally decreases with increasing frequency in the EN 50065-1 A Band.



2.6 MODULATION SCHEMES FOR PLC SYSTEM DESIGN

As the properties of power line channels differ considerably from other well known

channels, special care is necessary to select a modulation scheme that uses the high capacity

of these channels optimally and offers good noise robustness. The following section analyzes

some modulation schemes that come into consideration to find an optimal solution for PLC

systems.

A. Single Carrier Modulation for PLC

To modulate digital signals onto the power lines, we can use many of the same

techniques widely implemented in wireless communication. Basic modulation techniques

such as phase shift keying (PSK); Frequency Shift Keying (FSK), minimum shift keying

(MSK) and Gaussian Minimum Shift Keying (GMSK) can be used for low data rate

communication. Other more advanced techniques such as M-ary PSK (MPSK), M-ary

quardrature amplitude modulation (MQAM), M-ary FSK (MFSK) and orthogonal frequency

division multiplexing (OFDM) can be used when higher data rates are desired. A thorough

study of single carrier modulation techniques is given.

B. Spectrum Modulation

Spread spectrum techniques (SST) seem to be a good choice for PLC due to their

immunity against selective attenuation and all kinds of narrow band interference. An

additional interesting feature of SST, especially with regard to EMC is the low power spectral

density of the transmitted signals. Moreover, media access can be accomplished by code

division multiple access (CDMA), offering multiple access without global coordination or

synchronization.

As with CDMA, the entire frequency band is open to each participant, so access does

not have to be coordinated. Each active participant, however, increases the background noise

for all others. The more participants become active, the higher the probability of mutual

disturbance. Therefore, there is a trade-off between quality of service and permissible number

of active participants. The crucial figure in this context is the so called processing gain (PG),

the ratio of the bandwidth of the transmitted signal and the message bandwidth after

conventional modulation. Pg should be between 10 and 100 for acceptable performance. The

number of participants must, however, always remain smaller than PG; otherwise, robustness

against interference is completely lost. In a properly designed CDMA system so called

graceful degradation is found, indicating that each new participant will generate only a small

well controlled portion of interference for the others.



For the reasons listed above, most experts in the field have concentrated on

multicarrier techniques, in particular orthogonal frequency division multiplexing (OFDM).

C. Orthogonal Frequency Division Multiplexing

OFDM was adopted by the many researchers because of its robustness to noise and

the fact that a parallel FDM sub bands. The main problem is using OFDM in wireless

networks is frequency offset, caused by doppler effects when the user is moving. The

Doppler Effect wills cause performance degradation, but in power line networks there are no

moving devices, and thus no Doppler effect. The other problem is timing offset, which can be

mitigated by offset estimation and compensation. Orthogonal frequency division multiplexing

(OFDM) modulation technique can achieve much higher bandwidth efficiency than spread

spectrum systems and it allows an extremely flexible allocation of a given channel bandwidth

, because of its information allocation property to different carrier sub bands, OFDM is very

robust against narrow band interferences and frequency selective fading. Furthermore

combined with a well designed interleaving and forward error correction coding schemes,

OFDM can be robust against impulsive noise, so it is taken for granted that the OFDM can be

an ideal choice to achieve high rate digital transmission over low voltage power line.

2.7 ADVANTAGES AND DISADVANTAGES OF POWER LINE

Some advantages of the power line communication

i) The power grid is ubiquitous. Usually where human habitation exists, it is covered by low

voltage network, owing the wide geographic coverage of this network.

ii) The power grid offers last-mile connectivity. As long as there is a wall socket or outlet,

house appliances and electrical industrial equipment are connected to the low voltage

network. With Internet capable electronic equipment, even people are connected to this

network. Coupled with the capability of provide a permanent-access, two-way, always-online

Connection, 24 hours a day, the power grid emerges as a significant competitor in the last-

mile connectivity.

iii) The power grid supports information-based services with strong growth potential.

Presently, the current speed of data transmission using power lines is in the order of 1 Mbps.

But many useful services are already feasible with data transmission in the kbps range.

Broadband services may be feasible in the near future when speeds of more than 10 Mbps are

Achieved.

iv) The power grid is already in place thus enhancing cost effectiveness. To the energy sector,

this is a very important aspect. In order to achieve a comparable network as the power grid, it



would generally require tremendous investment for other forms of local telecommunications

access. So the energy supply already has at its hands a very large telecommunication network

ready for exploitation.

Some disadvantages of the power line communication are

i) Power lines represent a particularly difficult communication environment. At frequencies

of interest to communication, the cable attenuation is usually very large, and thus, repeaters

may be required for this compensation. Since electronic devices are also connected to the

power lines, the issue of electromagnetic compatibility has to be addressed. Most

importantly, channel parameter, such as noise level, impedance and attenuation, fluctuates

with time and load.

ii) Power line communication technology is still in the development stage; it is young and

still evolving. The recent rapid advancement in microprocessor technology and the

development of complex modulation techniques have enabled research into high speed and

high frequency power line communication systems, taking into account that the power line is

an onerous environment.

iii) There is a lack of standardization and interoperability of power line communication

relevant products. The CENELEC (European Committee for Electro technical

Standardization) EN (European Norm) 50065-1 standard [2], for example, allows a frequency

band that is very narrow, and thus, restricts the capability to deploy modern voice or data

systems. Although presently there are power line communication relevant products, they have

Difficulties to communicate with each other, such as X10 and Echelon Lon Works products,

since most of them are sole-proprietary.

iv) The commercial incentives to exploit power line communication infrastructure have not

been clear until recently. The main aim of power line communication used to be reducing

operational costs of the energy supply sector such as automatic meter reading (AMR).



CHAPTER 3

DETECTION AND CONTROL SYSTEM

The proposed control system for the detection of illegal electricity usage is shown in

Fig.3.1. PLC signalling is only valid over the low voltage VAC power lines. The system

should be applied to every low-voltage distribution network. The system given in Fig.

Belongs only one distribution transformer network and should be repeated for every

distribution network. Although the proposed system can be used uniquely, it is better to use it

with automatic meter reading system. If the AMR system will be used in any network, the

host PLC unit and a PLC modem for every subscriber should be contained in this system. In

Fig., the host PLC unit and other PLC modems are named PLC1A, PLCNA and are used for

AMR. These units provide communication with each other and send the recorded data in

kilowatt-hour meters to the PLC unit. In order to detect illegal usage of electrical energy, a

PLC modem and an energy meter chip for every subscriber are added to an existing AMR

system. As given in Fig. 3.5, PLC1B, PLCNB and energy meter chips belong to the detector.

The detector PLC s and energy meters must be placed at the connection point between

distribution main lines and subscriber’s line. Since this connection point is usually in the air

or at underground, it is not suitable for anyone to access, such that its control is easy. The

main procedure of the proposed system can be summarized as follows.PLC signalling must

be in CENELEC standards. In Europe, CENELEC has formed the standard EN-50 065-1, in

which the frequency bands, signalling levels, and procedures are specified. 3–95 kHz is

restricted for use by electricity suppliers, and 95–148.5 kHz is restricted to consumer use.

The recorded data in kilowatt-hour meters for every subscriber are sent to host PLC modem

via PLC modems, which is placed in subscriber’s locations. On the other hand, energy meter

chips are located at the connection points and read the energy in kilowatt-hours and also send

the data to host PLC unit. This proposed detector system has two recorded energy data in host

PLC unit, one, which comes from the AMR-PLC, and the other, which comes from the PLC

modem at the connection points. These two recorded energy data are compared in the host

PLC. If there is any difference between two readings, an error signal is generated. This means

that there is an illegal usage in the network. After that, the subscriber address and error signal

are combined and sent to the central control unit. If it is requested, a contactor may be

included to the system at subscriber locations to turn off the energy automatically, as in the

case of illegal usage.



Figure3: Schematic illustration of detection system of illegal electricity usage

The main elements of PLC modem are ST7537HS1 produced by SGS and 707VX-

T1002N transformer Produced by Toko Inc. The ADE7755 is an accurate electrical energy

measurement IC intended for use in single phase distribution systems, produced by Analog

Device. The main circuits of one detector system are carried out in the conditions of

laboratory.



Fig 3.1: Illegal detector system of one subscriber

3.1. SIMULATION:

The system model and simulation of the detection system of illegal electricity usage is

shown in Fig. 4. It contains a host PLC modem, an energy meter chip and its PLC modem, an

electromechanical kilowatt-hour meter and its PLC modem, and an optical reflector sensor

system is loaded at the same phase of the power grid. The energy value at the

electromechanical kilowatt-hour meter is converted to digital data using by optical reflector

sensor. Disk speed of the kilowatt-hour meter is counted and obtained data is sent to PLC

modem as energy value of the kilowatt-hour meter. At the system model, an illegal load may

be connected to the power line before the kilowatt-hour meter via an S switch. While only a

legal load is in the system, two meters are accorded each other to compensate for any error

readings. The host PLC unit reads two recorded data coming from metering PLC units. If the

S switch is closed, the illegal load is connected to the system, and therefore two recorded

energy values are different from each other.



Fig 3.2: System simulation and modelling of the detection system of illegal electricity usage for

electromechanical kilowatt-hour meters

The host PLC unit is generated when it received two different records from the same

subscriber. This is the detection of the illegal usage for interested users. In these tests, the

carrier frequency is selected at 132 kHz, which is permitted in the CENELEC frequency

band. In real applications the AMR systems may be designed in CENELEC bands. The data

rate between the host and other PLC modems is 2400 b/s.

Data signalling between PLC modems has a protocol, which includes a header,

address, energy value data, error correction bits, and other serial communication bits such as

parity and stop bits. The protocol may also be changed according to the properties of the

required system and national power grid architecture. Fig.5 shows the detection system for an

electromechanical kilowatt-hour meter system. In the digital energy meter system, the

recorded energy may be received in the digital form directly using the port of the meter.

Therefore, there is no need for an optical reflector system in digital meters.

The results of the tests show that this system may be solve this problem economically

because of the budget of the proposed system is approximately 20-25 USD per a subscriber.

It is very economical and reliable solution when it is compared with economical lost caused

by illegal usage.



CHAPTER 4

OVER VIEW OF THE PROPOSED DETECTOR SYSTEM

The proposed detector system is the equipment and procedure for controlling more

remote stations from a master control station. It includes PLC modems, energy meters,

control logics, and the system software. The PLC modems are host and target modems for

two-way communications to and from the host station and the remotely controlled targets.

The energy meters include metering chips and some circuit elements; the control and logic

units compare and generate the error signal in the Illegal usage.

Fig 4: Effects of distance of the source-receiver on the loss for various

The system software has two parts: assembler program for the micro controller and

the operating software for the management of the overall system. Operating software may be

downloaded from a PC and should be placed in the main center of the system.

An AMR system including an illegal detector performs the following functions.

1) Every user has two PLC modems; one is for AMR and the other is used to send the data

from second energy meter chip to host PLC modem.

2) An energy meter must be installed in the connection box between a home line and main

power lines.

3) The host PLC unit must be placed in the distribution transformer and the configuration of

the addressing format of PLC signalling must be designed carefully.

Dept. of Electrical & Electronics Engg Page 19


4) Operating software must be designed for the information of every subscriber in every sub

power network: subscriber identification number, billing address, etc……..

5) The system has two values of the energy consumption for every user, so if there is a

difference between them, an error signal is generated for the illegal user,

6) The proposed equipment is the only one distributed in the power network. So this system

should be repeated for all distribution power networks. All host units in each distribution

transformer may be connected to only one main center station via phone lines, fiber-optic

cable, or RF links.

7) Host PLC modem and its controller must include two addresses per every user; one is

AMR and the other for energy meter. These two addresses must be selected as sequently.

Fig 4.1: Bit-error probability with frequency and load impedance for 1000-m line

Fig 4.2 The effects of line length (m) on the bit error probability

Results and the variations of the measurements are shown in Fig. The relations

between frequency, length, and bit-error probability are given in these figures. Research work

has been taking place in the CPRI, Bangalore for the remote metering and detection of power

theft and will soon be helpful to electricity boards in India.



CHAPTER 5

CONCLUSION

The proposed detector system to determine illegal electricity usage via power line

communications is examined in the laboratory conditions. Results proved that if AMR and

detector system are used together illegal usage of electricity might be detected. Once this

proposed detection systems are tried in real power lines, the distribution losses in India can be

reduced effectively.

A detector system to determine illegal electricity usage via power line

communications is designed and proposed. The proposed system is examined in laboratory

conditions. Obtained results from this study show that if the AMR and detector system are

used together, illegal usage of electricity may be detected. The proposed system has not been

tried in real power lines due to nonexistent AMR system in our country. In the near future,

combined AMR and detector systems will be tried in our country as explained above. One of

the main aims of this study is to start new discussions and propose solutions in this field,

because illegal usage is a serious problem in our country. And may also be in other parts of

the world.



REFERENCES

[1] I. H. Cavdar, “A Solution to Remote Detection of …” IEEE Transactions on power

delivery, Vol. 19, No. 4, October 2004.

[2] I. H. Cavdar, “Performance analysis of FSK power line communications systems over the

time-varying channels: Measurements and modelling,” IEEE Trans. Power Delivery, vol. 19,

pp. 111–117, Jan. 2004.

[3] Yoshinori Mizugai and Masahiro Oya “World Trends in Power Line Communications”

Mitsubishi Electric ADVANCE March 2005.

[4] Tom D Tamarkin “Automatic Meter Reading”, Public Power magazine Volume50,

Number5 September-October 1992.

[5] Online; “www.wikipedia.org/powerlinecommunication”

[6] Proceedings, ETP’06, Dept of EEE, S.R.K.R.E.C.


Remote Detection of Illegal Electricity Usage

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