advanced metering infrastructure over power line communication

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The University of Jordan, Amman-Jordan

Faculty of Engineering and Technology

Electrical Engineering Department

Advanced Metering Infrastructure over Power Line Communication

By:

Ahmad S. Abu Doush (ID #: 0094289)

Anas I. Abu Al-Rub (ID #: 0094298)

Supervised by:

Dr. Mohammed Hawa

Submitted in partial fulfillment of the requirements for

B.Sc. Degree in Electrical Engineering

January 2014


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ACKNOWLEDGEMENTS

We would like to thank our supervisor Dr. Mohammed Hawa for all his guidance, support,and patience during this year. Special thanks to Engineer Ziad Al-Khatib for all his help and

kindness. Not forgetting also to thank the staff of The University of Jordan for their efforts

throughout the years.

In addition we are grateful to our families and friends for supporting us in this important

stage of our lives.


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ABSTRACT

Advanced Metering Infrastructure is a feature that is highly recommended these days by

utilities and customers for monitoring and controlling the flow of electricity, water, and gas in

a grid.

One of the techniques that are used to establish a connection between the utility and the

customer is Power Line Communication. This technique uses the existing power lines to

transfer information in a two-way mode between the utility and the costumer.

This project simulates these processes over a small smart grid that can be expanded to a

larger one by considering more powerful equipment.


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TABLE OF CONTENTS

ACKNOWLEDGEMENTS iiABSTRACT iii

TABLE OF CONTENTS iv

CHAPTER 1: INTRODUCTION 1

1.1 CONCEPTUAL OVERVIEW 2

1.2 PROJECT OVERVIEW 3

CHAPTER 2: SMART GRIDS AND SMART METERING 4

2.1 OVERVIEW 5

2.2 PURPOSE 11

2.3 COMMUNICATION AND PROTOCOLS 11

2.4 DATA MANAGEMENT 12

CHAPTER 3: SMART GRID NETWORKS AND POWER LINE

COMMUNICATION 13

3.1 OVERVIEW 14

3.2 POWER LINE COMMUNICATION (PLC) 16

CHAPTER 4: HARDWARE 18

4.1 ELECTRICITY METER 20

4.1.1 Overview 20

4.1.2 Specifications 21

4.1.3 Methodology 22

4.1.4 Auxiliary Hardware 23


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4.2 APPLICATION PROCESSOR 24

4.2.1 Overview 24


4.2.3 Block Diagram (Raspberry Pi) 25

4.3 POWER LINE ADAPTER 25

4.1.1 Overview 25


4.1.3 Block Diagram and Methodology 27

CHAPTER 5: SOFTWARE 28

5.1 COMMUNICATION STACK 29

5.1.1 Application Layer 30

5.2 GENERAL SYSTEM ARCHITECTURE 32

5.2.1 Addressing Methodology 33

5.3 APPLICATION PROGRAM INTERFACE 33

5.4 UTILITY'S SOFTWARE 34

5.5 METER'S SOFTWARE 39

5.5.1 Energy Consumption 39

5.5.2 Interoperability 41

5.6 USER'S SOFTWARE 41

5.7 SECURITY 42


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CHAPTER 6: CONCLUSION 44

6.1 WORK, PROBLEMS, AND LESSONS 45

6.2 FUTURE PROPOSALS 46

6.2.1 Communication Threats 46

6.2.2 Power Line Communication Simulation 47

6.2.3 Deployment of Additional Nodes 49

REFERENCES 50


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Chapter 1: Introduction

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CHAPTER 1: INTRODUCTION


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1.1 CONCEPTUAL OVERVIEW

Advanced Metering Infrastructure (AMI) is a service utilized in Smart Grids. It allows the

utility to measure and control the electricity flow in a grid in a two-way communication mode

(Full Duplex). The user can also observe the electricity being consumed by the load with a

less permissions to control the flow.

Why AMI? Electricity providers suggest that from a consumer point of view, AMI offers

potential benefits including:

1- Improving power reliability and quality.

2- Enhancing capacity and efficiency of existing electric power networks.

3- Enabling predictive maintenance and self-healing responses to system disturbances.

4- Facilitating expanded deployment of renewable energy sources.

5- Automating maintenance and operation.

6- Reducing greenhouse gas emissions by enabling electric vehicles and new power sources.

7- Presenting opportunities to improve grid security.

8- Increasing consumer choice.

9- Enabling new products, services, and markets.

There are many ways to exchange data over smart grids. One method by which a

communication takes place in a smart grid is Power Line Communication (PLC). It uses the

same power lines that are used for transmitting the electricity to transmit the information over

the grid by implying different techniques of modulation such as Frequency Division

Multiplexing. There are complex hardware devices used in this process such as Phase Locked

Loops. By this method there is no need for a new infrastructure to exchange data, thus, saving

money.


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1.2 PROJECT OVERVIEW

There are 4 main parts in our project:

The Smart Meter (which consists of an Electricity Meter and a Raspberry Pi kit), The Power

Line Adapter, The User's Interface installed on the user's PC, and finally The Utility's

Interface installed on the utility's PC.

The electricity meter part measures the electricity consumed by the load and produces 1000

impulses per 1 Kilowatt-hour. These impulses are fed into the Raspberry Pi kit to be

analyzed, sent to the user wirelessly and to the utility over the power lines using the power

line adaptor. We will discuss those parts in more details in chapters four and five later on in

this documentation.

Figure 1.1: An end-to-end illustration for connections and hardware.


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Chapter 2: Advanced Metering Infrastructure and Smart Grids

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CHAPTER 2: ADVANCED METERING INFRASTRUCTURE AND SMART

GRIDS


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2.1 OVERVIEW

A smart meter is an electrical meter that reads consumption of electric energy and manipulates

it to be sent to the utility for monitoring and billing purposes through a network called smart

grid.

Advanced Metering infrastructure includes home network systems, including communicating

thermostats and other in-home controls, smart meters, communication networks from the

meters to local data concentrators, back-haul communications networks to corporate data

centers, meter data management systems (MDMS) and, finally, data integration into existing

and new software application platforms. Additionally, AMI provides a very intelligent step

toward modernizing the entire power system. Figure 2.1 below graphically describes the AMI

technologies and how they interface:

Figure 2.1: An overview of AMI.


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At the consumer level, smart meters communicate consumption data to both the user and the

service provider. Smart meters communicate with in-home displays to make consumers more

aware of their energy usage. Going further, electric pricing information supplied by the

service provider enables load control devices like smart thermostats to modulate electric

demand, based on pre-established consumer price preferences. More advanced customers

deploy distributed energy resources (DER) based on these economic signals. And consumer

portals process the AMI data in ways that enable more intelligent energy consumption

decisions, even providing interactive services like prepayment.

The service provider (utility) employs existing, enhanced or new back office systems that

collect and analyze AMI data to help optimize operations, economics and consumer service.

For example, AMI provides immediate feedback on consumer outages and power quality,

enabling the service provider to rapidly address grid deficiencies. And AMIs bidirectional

communications infrastructure also supports grid automation at the station and circuit level.

The vast amount of new data flowing from AMI allows improved management of utility

assets as well as better planning of asset maintenance, additions and replacements. The

resulting more efficient and reliable grid is one of AMIs many benefits.

How does AMI support the vision for the Smart Grid? Initially, Automated Meter Reading

(AMR) technologies were deployed to reduce costs and improve the accuracy of meter reads.

A growing understanding of the benefits of two-way interactions and communication between

system operators, consumers and their loads and resources led to the evolution of AMR into

AMI. The vision of the Smart Grid reinforces the need for AMI for the following reasons:

1- Motivation and inclusion of the consumer is enabled by AMI technologies that provide the

fundamental link between the consumer and the grid.

2- Generation and storage options distributed at consumer locations can be monitored and

controlled through AMI technologies.

3- Markets are enabled by connecting the consumer to the grid through AMI and permitting

them to actively participate, either as load that is directly responsive to price signals, or as part

of load resources that can be bid into various types of markets.

4- AMI smart meters equipped with Power Quality (PQ) monitoring capabilities enable more

rapid detection, diagnosis and resolution of PQ problems.


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5- AMI enables a more distributed operating model that reduces the vulnerability of the grid

to terrorist attacks.

6- AMI provides for self-healing by helping outage management systems detect and locate

failures more quickly and accurately. It can also provide a ubiquitous distributed

communications infrastructure having excess capacity that can be used to accelerate the

deployment of advanced distribution operations equipment and applications.

7- AMI data provides the granularity and timeliness of information needed to greatly improve

asset management and operations.

Although the electric grid is considered an engineering marvel, we are stretching its

patchwork nature to its capacity. To move forward, we need a new kind of electric grid, one

that is built from the bottom up to handle the groundswell of digital and computerized

equipment and technology dependent on it, and one that can automate and manage the

increasing complexity and needs of electricity in the 21st century.

The grid refers to the electric system that may support all or some of the following four

operations: electricity generation, electricity transmission, electricity distribution, and

electricity control. It is a network of transmission lines, substations, transformers and more

that deliver electricity from the power plant to your home or business. Its what you plug into

when you flip on your light switch or power up your computer.

A new and more intelligent electric system, A Smart Grid is required that combines

information technology (IT) with renewable energy to significantly improve how electricity is

generated, delivered, and consumed. A Smart Grid is an enhancement of the 20th century

power grid. The traditional power grids are generally used to carry power from a few central

generators to a large number of users or customers. In contrast, the Smart Grid uses two-way

flows of electricity and information to create an automated and distributed advanced energy

delivery network. It provides utility companies with near-real-time information to manage the

entire electrical grid as an integrated system, actively sensing and responding to changes in

power demand, supply, costs, and emissions-from rooftop solar panels on homes, unmanned

wind farms, and energy-intensive factories.


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Traditional grid Smart grid

Electromechanical Digital

One-way communication Two-way communication

Centralized generation Distributed generationFew sensors Sensors all over the grid

Manual monitoring Automatic monitoring

Manual restoration Automatic healing

Failures and blackouts Adaptive and islanding

Limited control Pervasive control

Few costumer choices Many costumer choices

Table 2.1: Comparison between Traditional grids and smart grids

Let us consider demand profile shaping. Since lowering peak demand and smoothing demand

profile reduces overall plant and capital cost requirements, in the peak period the electric

utility can use real-time pricing to convince some users to reduce their power demands, so that

the total demand profile full of peaks can be shaped to a nicely smoothed demand profile. An

academic study based on existing trials showed that homeowners' electricity consumption onaverage is reduced by approximately 3-5%.

More specifically, the Smart Grid can be regarded as an electric system that uses information,

two-way, cyber-secure communication technologies, and computational intelligence in an

integrated fashion across electricity generation, transmission, substations, distribution and

consumption to achieve a system that is clean, safe, secure, reliable, resilient, efficient, and

sustainable. This description covers the entire spectrum of the energy system from the

generation to the end points of consumption of the electricity. The ultimate Smart Grid is a

vision. It is a loose integration of complementary components, subsystems, functions, and

services under the pervasive control of highly intelligent management-and-control systems.

Given the vast landscape of the Smart Grid research, different researchers may express

different visions for the Smart Grid due to different focuses and perspectives.


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In order to realize this new grid paradigm, National Institute of Standards and Technology -

US (NIST) provided a conceptual model (as shown in Figure 2.2), which can be used as a

reference for the various parts of the electric system where Smart Grid standardization work is

taking place. This conceptual model divides the Smart Grid into seven domains. Each domain

encompasses one or more Smart Grid actors, including devices, systems, or programs that

make decisions and exchange information necessary for performing applications. The brief

descriptions of the domains and actors are given in Table 2.2

Figure 2.2: NIST Model for Smart Grids.


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Domain Actors in the domain

Customers The end users of electricity. May also generate, store, and manage the

use of energy

Markets The operators and participants in electricity marketsService providers The organizations providing services to electrical customers and

utilities

Operations The managers of the movement of electricity

Bulk generation The generators of electricity in bulk quantities. May also store energy

for later distribution

Transmission The carriers of bulk electricity over long distances. May also store and

generate electricity

Distribution The distributors of electricity to and from customers. May also store

and generate electricity

Table 2.2: Domains and Actors in the NIST Smart Grid Conceptual Model.

The smart infrastructure system is the energy, information, and communication infrastructure

underlying the Smart grid. It supports two-way flow of electricity and information. Note thatit is straightforward to understand the concept of two-way flow of information. Two-way

flow of electricity implies that the electric energy delivery is not unidirectional anymore. For

example, in the traditional power grid, the electricity is generated by the generation plant, then

moved by the transmission grid, the distribution grid, and finally delivered to users. In an

Smart Grid, electricity can also be put back into the grid by users. For example, users may be

able to generate electricity using solar panels at homes and put it back into the grid, or electric

vehicles may provide power to help balance loads by peak shaving (sending power back to

the grid when demand is high). This backward flow is important. For example, it can be

extremely helpful in a micro grid that has been islanded due to power failures. The micro

grid can function, albeit at a reduced level, with the help of the energy fed back by the

customers. The smart infrastructure can be divided into three subsystems: the smart energy

subsystem, the smart information subsystem, and the smart communication subsystem.

The smart energy subsystem is responsible for advanced electricity generation, delivery, and

consumption. The smart information subsystem is responsible for advanced information


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metering, monitoring, and management in the context of the Smart Grid. Finally, The smart

communication subsystem is responsible for communication connectivity and information

transmission among systems, devices, and applications in the context of the Smart Grid .

Note that the reason why we separate information subsystem and communication subsystem is

to get a handle on the involved complexity of the Smart Grid as a system of systems.

Drawing on the above definition, smart grid investment should support Resilience which

means that smart grids will facilitate changes by enabling additional dispersed supply and by

enhancing corrective capabilities where problems occur, and Environmental Performance

which implies that the smart grid is expected to reduce energy use by costumers, as well as,

energy losses within the grid. These results require vital information to be available to the grid

operators; distribution automation furnishes these requirements.

2.2 PURPOSE

Since the deregulation of electricity has been a problem in the last few years, and market-

driven pricing methodology has become more efficient these days, utilities have been looking

for a way to match consumption with generation. Smart meters allow measuring consumption

by the time of day and season, thus, allowing price setting agencies to introduce different

prices for consumption. Smart meters also provide the feature of diagnosis of power quality

problems by measuring surge voltages and harmonic distortion.

2.3 COMMUNCATION AND PROTOCOLS

One of the major issues in smart meters is communication. A smart meter must be able to

deliver information securely and reliably to the utility. Considering the different medias and

locations of meters, this issue can be resolved. Among the solutions proposed are: the use of

cell and pager networks, satellite, licensed radio, combination licensed and unlicensed radio,

and power line communication with a security protocol such as SSL (Security Sockets Layer).


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The ANSI C12.18 is an example for protocols used for communication. It is an ANSI standard

that describes a protocol used for two-way communications with a meter. The C12.18

standard is written specifically for meter communications via an ANSI Type 2 Optical Port.

2.4 DATA MANAGEMENT

Another critical issue for smart meters is the information technology at the utility that

integrates the smart meters with the utility applications. Having PLC technologies that are

standardized and compatible used within the home over a Home Area Network (HAN) is also

a critical issue. The HAN allows HVAC systems and other household appliances to

communicate with the smart meter, and from there to the utility. The two main broadband

PLC technologies selected are: HomePlug AV / IEEE 1901 based on broadband (OFDM)

technology. Also, ITU-T G.hnem based on existing low frequency narrowband (OFDM)

technology.


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Chapter 3: Smart Grid Networks and PLC

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CHAPTER 3: SMART GRID NETWORKS AND POWER LINE

COMMUNICATION


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3.1 OVERVIEW

The Smart Grid is a network of networks comprising many systems and subsystems. That is,

many systems with various ownership and management boundaries interconnect to provide

end-to-end services between and among stakeholders as well as between and among

intelligent devices.

However, to fully realize the Smart Grid goals of vastly improving the control and

management of power generation, transmission and distribution, and consumption, the current

state of information network interconnectivity must be improved so that information can flow

securely between the various actors in the Smart Grid. This information must be transmitted

reliably over networks and must be interpreted consistently by applications. This requires that

the meaning, or semantics, of transmitted information be well-defined and understood by all

involved actors.

In Smart Grid Networks, control and data messages are exchanged. Clouds are used to

illustrate networks handling two-way communications between devices and applications. As

in Figure 3.1 the devices and applications are represented by the boxes and belong to the

seven different domains: Customer, Generation, Transmission, Distribution, Operations,

Markets, and Service Provider.


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Figure 3.1: Smart Grid Networks for Information Exchange.

Example applications and devices in the Customer domain include: smart meters, appliances,

thermostats, energy storage, electric vehicles, and distributed generation.

Applications and devices in the Transmission or Distribution domain include: phasor

measurement units (PMUs) in a transmission line substation, substation controllers,

distributed generation, and energy storage. Applications and devices in the Operations domain


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include supervisory control and data acquisition (SCADA) systems and computers or display

systems at the operation center.

The physical or logical links within and between these networks, and the links to the network

end points, could utilize any appropriate communication technology either currently available

or developed and standardized in the future.

Within each network, a hierarchical structure consisting of multiple network types may be

implemented. Some of the network types that may be involved are Home Area Networks,

Personal Area Networks, Wireless Access Networks, Local Area Networks, and Wide Area

Networks. On the basis of Smart Grid functional requirements, the network should provide the

capability to enable an application in a particular domain to communicate with an application

in any other domain over the information network, with proper management control of all

appropriate parameters (e.g., Who can be interconnected? Where? When? How? ). Many

communication network requirements need to be met including data management control, as

well as network management such as configuration, monitoring, fault detection, fault

isolation, addressability, service discovery, routing, quality of service, and security. Network

security is a critical requirement to ensure that the confidentiality, integrity, and availability of

Smart Grid information, control systems, and related information systems are properly

protected.

Given the diversity of the networks, systems, and energy sectors involved, ensuring adequate

security is critical so that a compromise in one system does not compromise security in other,

interconnected systems. A security compromise could impact the availability and reliability of

the entire electric grid. In addition, information within each specific system needs to be

protected. Security includes the confidentiality, integrity, and availability of all related

systems.

3.2 POWER LINE COMMUNICATION

Power Line Communication refers to the process of carrying data over a power line

simultaneously with AC electric power transmission. It is also known as Power Line Carrier,

or Power Line Networking (PLN). Technically, in PLC power electronics are used to

manipulate high-voltage waveforms for signal and information oriented applications.


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Power line Communication technologies are used in different applications, such as home

automation, internet access, and smart grids. Most PLC technologies use one type of wires

such as premises wiring. However, some can use two levels such as premises wire combined

with distribution network. There are variety of data rates and frequencies used in different

situations.

Power line communication systems operate by modulating a carrier and adding this signal to

the wiring system. The propagation problem is a limiting factor in PLC technologies because

the power transmission system is already designed for carrying electricity at typical

frequencies of 50 or 60 Hz.

Power wires have a limited ability to carry higher frequencies. The main problem in

determining the frequency of the modulated carrier signal is to consider the interference with

radio services. Some jurisdictions require uses to be below 500 KHz or in unlicensed radio

bands.

Data limits and distance ranges widely over different standards. High data rates generally

imply short distances. However, it eliminates the need for installation of network cables with

high data rates in a building for example.

Broadband over power line (BPL) is a protocol to send two-way data over existing AC

medium voltage electrical transmission wiring between transformers, and AC low voltage

wiring between transformer and costumer outlets (typically 110 to 240V). Using power lines

saves additional costs for building a whole new infrastructure. Modern BPL uses frequency-

hopping spread spectrum technique to avoid using frequencies actually in use.


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Chapter 4: Hardware

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CHAPTER 4: HARDWARE


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As illustrated previously in chapter one, our projects consists of four main parts:

The Smart Meter (which consists of an Electricity Meter and a Raspberry Pi kit), The Power

Line Adapter, The User's Interface installed on the user's PC, and finally The Utility's

Interface installed on the utility's PC.

Figure 4.1: An end-to-end illustration for connections and hardware.


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We will discuss the first two parts in this chapter; The Smart Meter and The Power Line

Adapter, and leave parts three and four for the next chapter.

Figure 4.2: Hardware Block Diagram.

4.1 ELECTRICITY METER

4.1.1 Overview

The Electricity Meter senses the current and voltage signals and converts them into an

appropriate form to be fed to the analog-to-digital converters, these signal are then fed to the

chip inside the meter to calculate the electric energy consumed. We had two options: The

Intellix SM110 from GENERAL ELECTRIC, and the E1S-10T from KRIZIK.


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The meters has an integrated 100 A rated relay to disconnect and reconnect supply remotely to

provide utilities with the ability to manage situations as disconnecting power supply of

customers that have failed to pay their bills. We used an additional 16 A rated relay to

disconnect and reconnect some dispensable loads like AC loads to manage heavy demands at

peak times of use.

4.1.2 Specifications

Feature SM110 E1S-10T

Phases Single phase Single phase

Maximum current 100 A 100 A

Nominal voltage 230 V 20% 230 V 20%

Frequency 50 Hz or 60 Hz 50 Hz

Power consumption ~ 1 W 1.6 W

Relays -100 A overall supply

disconnect

-16 A dispensable load

disconnect

-100 A overall supply

disconnect

-16 A dispensable load

disconnect

Pulse outputs IEC 62053-31 IEC 62053-31

Table 4.1: Meters' Specifications.

We chose the E1S-10T model from KRIZIK because it was cheaper and simpler. The SM110

comes with an Ethernet port, and software which we didn't need because we designed our own

software using the Raspberry Pi kit.


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Figure 4.3: Output pulse waveform of IEC 62053-31.

4.1.3 Methodology

The SA4102ASA chip takes two signals; one from the voltage divider for the voltage signal,

and the other from an isolation amplifier connected to a shunt resistor for the current signal.

The voltage divider is used to make the voltage signal compatible with the voltage levels of

the chip. The isolation amplifier is to convert the current to a voltage signal, amplify it, and

protect the chip from voltage spikes and surge voltages on the line.

Internally in the chip, both signals are converted using analog to digital converters (ADCs),

and used to calculate the energy consumed by the load.


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4.1.4 Auxiliary Hardware

Figure 4.4: Main Relay Control Circuit.

Figure 4.5: Dispensable Relay Control Circuit.

Both relays are used for implementing the functions required by the AMI, and its controlled

by the application processor.


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4.2 APPLICATION PROCESSOR

4.2.1 Overview

The smart part of the meter relies mainly on the Application Processor, which handles the

process of reading the energy and converting it into an understandable format. It is also

responsible to the communication between the meter and the utility or home user.

For this purpose, we looked for a suitable device that can achieve the required tasks. We

found two options in the market, the Raspberry Pi kit and the Arduino Uno.

The main difference between both products is that the Raspberry Pi is a mini-computer, while

Arduino is a micro-controller; a subset of the functionality of Raspberry Pi.


Feature Raspberry Pi Arduino Uno

SoC Broadcom BCM2835 None

CPU 32-bit 700 MHz

ARM1176JZF-S core

8-bit 16 MHz

1T

ATmega328

GPU Broadcom VideoCore IV @

250 MHz

None

Memory (SDRAM) 512 MB (shared with GPU) 32 KB , with 2 KB SRAM

USB 2.0 ports 2 (via the built in integrated

3-port USB hub)

1 Port

Onboard storage SD card slot EEPROM 1 KB

Onboard Communication 10/100 Ethernet (8P8C)

IP2PC , UART , SPI

Serial UART , SPI

Power ratings 300 mA (1.5 W) 16 mA (80 mW)

Power source 5 Volt via MicroUSB 5 Volts or 3.3 Volts

Programing Software Linux-Based (Debian) Arduino IDE

Digital IO pins 17 pins 14 pins

Analog I/O pins 6 0

Table 4.2: Raspberry Pi and Arduino Specifications.


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We have chosen the RPi for the overall required specifications; including high processing

speed and high memory and storage capacity. Those are required for the smart meter

functions and applications (i.e. the webserver and SSH sessions and others). Also, the

Ethernet port is required for the PLC adaptor, which is not available in the Arduino kit.

4.2.3 Block Diagram (Raspberry Pi)

Figure 4.6: Raspberry Pi's Block Diagram.

4.3 POWER LINE ADAPTER

4.3.1 Overview

The Power Line Adapter modulates the data signals to be sent over power lines. It uses

electrical wires in the house to transfer data while simultaneously transferring traditional

power. Thus there is no need for additional wiring.

The basic concept of power line communication relies on the Coupling Transformer

(Isolation Transformer), which acts as the link between the channel (Power Lines) and the


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PLC adaptor ICs. Its used for isolating the system from the power lines for safety and to

couple the transmitting and receiving signals on only two wires.

All viewed adapters like: NETGEAR Power line AV 200 Mbps Nano Adapter Kit, D-Link

DHP-209AV Power Line AV 200 Mini Adapter Starter Kit, and TP-LINK TL-PA211 Power

Line Adapter had approximately the same features such as: HomePlug AV Standard, having

data rates of up to 200 Mbps, and an Ethernet interface. However the TP-LINK TL-PA211

Adapter was the only choice available at stores. The TL-PA211 can be plugged into power

sockets to establish a networking infrastructure. It has a built-in QoS and powerful AES

encryption. TL-PA211 provides users with stable, and high-speed data transfer rates of up to

200Mbps on a line length of up to 300 meters. By pushing the pair button on the adapters,

users can set up a hassle-free power line network within minutes, complete with 128-bit AES

encryption for network security and data protection.


Feature Specification

Standards and protocols HomePlug AV, IEEE802.3, IEEE802.3u

Interface 10/100Mbps Ethernet Port

Power consumption < 3 W

Range 300 M

Modulation technology OFDM

Advanced functions Built-in QoS feature

Intelligent channel adaption

Encryption 128-bit AES encryption

System requirements Windows 2000/XP/2003/Vista, Windows 7,

Mac, Linux

Table 4.3: Adapter's Specifications.


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4.3.3 Block Diagram and Methodology

Figure 4.7: Adapter's Block Diagram.

The coupling transformer is the first stage, and then a filter is used to block the line voltage

frequency. AR1500 IC consists of a Programmable Gain Amplifier (PGA) to amplify the

received signal and a higher order low pass filter to cancel the high frequency noise.

Also, it includes a line driver for transmitting the signal received from DAC in AR7400 IC.

PLL is used to synchronize with the received signal frequency so it can be demodulated.


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CHAPTER 5: SOFTWARE


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5.1 COMMUNICATION STACK

The protocols used are based on the TCP/IP stack, which is a complete set of protocols used

for networking. Its widely used across the world which gives more flexibility to implement it

in various fields. While The OSI Model has 7 layers, the TCP/IP stack which is the most

common Protocol suite in use today has 4.

Figure 5.1: TCP/IP Stack.

Application layer is the actual data transmitted or received between hosts (peers)

including higher level protocols such as SMTP, FTP, SSH, HTTP. In this project, the

application layer is considered to be predefined messages exchanged between the Server

(Utility) and Client (Meter).

Transport layer is the internetworking between two network processes, on either the local

network or remote networks separated by routers. Processes are addressed via "ports". TCP

(Transmission Control Protocol) was used as the transport layer in this project for various

advantages (discussed later).


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Network layer is the layer responsible for exchanging datagrams between networks. Its

considered to be the layer that establishes internetworking. It defines the addressing and

routing structures for the network stream between source and final destination. The primary

protocol used for the Network Layer in this project is the Internet Protocol, which definesIP

addresses.

Data Link layer is the networking methods used to describe the protocols used in the local

network and interfaces required to accomplish the transmission of Network Layer datagrams

to next hosts. For this project, PLC(Power line communication) is the main Data Link layer

used to exchange datagrams between hosts. Ethernetis also used between the main devices

(Raspberry Pi and Utility Server) and PLC modems. 802.11 (WLAN)was also used between

the Meterand the Home User.

5.1.1 Application Layer

The message in the application part of the packet is divided into two types.

The first type is the Meter to Utility message. It consists of a Meter ID field to indicate the

source of the message, the consumed energy (in Wh), Sequence of reading of the energy, and

flags to indicate specific states; such as main relay and dispensable relay statuses and

warnings for some cases (will be discussed later).
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Figure 5.2: Meter to Utility Message Format.

The second type is the Utility to Meter Message. It consists of the Meter ID field to specify

the targeted client (or clients), the current bill (in Fils) for the user, commands and

information; such as opening and closing the relays and the status of the bill (paid or not).

Figure 5.3: Utility to Meter Message Format.


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Some of the fields are unused and reserved for any future implementation functions and

ideas. The size of the fields where minimizedas much as possible to save bandwidth. The

values are sent as integers and bits (Flags) instead of characters which save more than half of

the bandwidth.

5.2 GENERAL SYSTEM ARCHITECTURE

The architecture used for this communication is based on Client-Server model.

Figure 5.4: Client-Server Model Used in Sockets.

The Server in this case is considered to be the utility's computer. It was written in VB.NET

language, and running on a Microsoft Windows based system. It provides Control and

Monitoringfor the meters using different functions such as: Collecting Data from all meters,

checking for billing information, analyzing the data for various purposes (displaying real time

consumption, monitoring the levels of consumption, and detecting any possibility of

overloading), and finally, sending commands based on these analysis: (opening over load

relay in case of overload protection, opening main relay, and disconnecting the meter if the

bill is not paid).

The smart meters are considered to be the client in this case, which acts as information

collecting points for the infrastructure. The functions accomplished by the client are:

Measuring consumed energy, recording it into a file, and sending the current energy

consumed to the utility, checking for billing status received from the utility and making

decisions according to the status, opening and closing main relay and dispensable relay upon

request from utility, checking for the case of possible fraud to warn utility about it, and


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finally, providing the home user with access to energy consumed and the bill via web page

that can be accessed through a WLAN.

5.2.1 Addressing Methodology

In this project, we designed the server to be able to communicate with a client or multiple

clients using the Meter ID field. This field provides the server with the ability to connect to

the clients in the following methods: Unicast:one-to-one (One meter only), Multicast:one-

to-many (group of meters), Broadcast: one-to-all (All meters in the network).This can be

done my using the Meter ID part of the message, the first 2 bytes (0xFFFF) is reserved for

the multicast group ID, and the last 2 bytes are reserved for the meter ID. If the Meter ID part

was set to 0xFFFFFFFF, this means its a broadcast message for all clients in the network.

5.3 APPLICATION PROGRAM INTERFACE (API)

Network Sockets:Its an end point communication flow across a network, and its used to

send information across the network like internet. It can be characterized by: Local socket

address (IP of the local host and port number), Remote socket address (used in TCP

connections only, because it can deal with several clients at once), and Protocol (Raw IP,

TCP, UDP, etc). In the operating system, the process creates a socket by referring it to a file

descriptor and uses it to forward the payloads to the corresponding processes and

applications. Socket is considered to be used in the transport layer and is independent of other

layers. So it doesnt require any implementations in the path of the packet (in routers and

switches which are considered Internet Layer and Data Link layer respectively).

Internet socket types have different forms including: Datagram sockets

(0T

Connectionless0T

sockets, which use User Datagram Protocol (UDP)), Stream sockets

(0TConnection-oriented 0Tsockets, which use Transmission Control Protocol (TCP)), and

Raw sockets (orRaw IP sockets), here the transport layer is ignored, and the packet headers

are made accessible to the process.

The type chosen in our system is the stream sockets; which has the many advantages

including: High reliability communication to assure the delivery of messages, keeping track
http://en.wikipedia.org/wiki/Connectionlesshttp://en.wikipedia.org/wiki/Connectionlesshttp://en.wikipedia.org/wiki/Connectionlesshttp://en.wikipedia.org/wiki/Connectionlesshttp://en.wikipedia.org/wiki/Connectionlesshttp://en.wikipedia.org/wiki/Connectionlesshttp://en.wikipedia.org/wiki/Connectionlesshttp://en.wikipedia.org/wiki/Connection-orientedhttp://en.wikipedia.org/wiki/Connection-orientedhttp://en.wikipedia.org/wiki/Connection-orientedhttp://en.wikipedia.org/wiki/Connection-orientedhttp://en.wikipedia.org/wiki/Connection-orientedhttp://en.wikipedia.org/wiki/Connection-orientedhttp://en.wikipedia.org/wiki/Connection-orientedhttp://en.wikipedia.org/wiki/Connection-orientedhttp://en.wikipedia.org/wiki/Connectionless


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of connection if its lost, invincible to errors by using Checksum (Over Raw sockets), and

data arrives in-order, duplicate data is discarded, and includes Traffic Congestion Control.

The sockets used in this system are programmed using C (in Raspberry Pi) and VB.NET (in

the utility's software).

5.4 UTILITY'S SOFTWARE

The software was written in VB.NET using Microsoft Visual Studio 2010.

As shown below, the utility employee can choose the listening IP address for the connections

requested by the clients if the server has more than one interface. When the client connects to

the server, its automatically added to the list box.

Figure 5.5: Meter Data Manager.


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Once there are clients listed, the employee can select any meter and view its current status;

including The IP of the client, Energy Consumed and Bill calculated and the relays status.

When a packet arrives from a client, its directly logged into a file specified for the related

meter. This file is used to display the client status and to plot its energy consumption.

The software collects the bill status for the clients from a file that shows if the bill is paid or

not by the customer. And based on that, it sends the appropriate commands to the meters

automatically.

In the Client group box, the employee can manually send commands to the selected meter,

or to enter the desired Meter ID in the box.

A real-time graph is located in the Client group box, and it shows the current consumption by

the selected meter in the list box.

Figure 5.6: Listening thread.


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Figure 5.7: Logging thread.


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Figure 5.8: Billing Management.

The energy consumption can be visualized. Also the employee has the choice of choosing the

desired meters to plot their consumption.

A critical level of energy consumption can be set, and if the consumption exceeds this level,

the server will send a message to the meters to trip the over load relay.

The dynamiccheck box switches the graph into a real-time plot to show the current energy

consumed by the selected meters.


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Figure 5.9: Consumption Plotter.

Figure 5.10: Dispensable Load Relay Tripping.


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5.5 METER'S SOFTWARE

The code was written for the Raspberry Pi in C Language and compiled on GCC (GNU

Compiler Collection).

It was divided into 5 files and linked together using different libraries. SharedAMI.h, it is the

header file used to define meter parameters, such as: Number of pulses per Kwh, meter ID,

and multicast ID, sharedTCP.h: It is the header file used to Initialize sockets variables. (The

parameters defined in this file are: IP address of the utility server, ports for communication,

and timer for sending packets), sharedAMI.c: the code file for the meter functions including:

Reading energy consumed from the meter, opening and closing relays, logging information,

sharedTCP.c: The code file for meter sockets function including: Initialization of network

sockets, listening and sending threads, messages packing and unpacking functions, and

Main.c: The main compiled file which creates different threads including: Meter thread,

listening thread, and publishing thread.

Different libraries were used for this code: : Used to create multiple threads,

: Used to define the API to communicate with Raspberry Pi GPIO (General

Purpose Input/Output), and (, , , ):

Used for internet sockets.

5.5.1 Energy Consumption

The IEC 62053-31 standard specifies the output pulses of a Digital meter. If this protocol

was implemented in any digital meter, the Raspberry Pi can read the energy consumed from

the pulse output port on the meter. Every pulse generated from the meter corresponds to a

value of energy consumed, in our case, every 800 pulses the energy consumed is 1 KWh. The

pulse can be read by the Raspberry Pi through a GPIO pin, and detected using the interrupts

service routines (ISR)handled by the Raspberry Pi library.


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The output wave form of the meter is as shown below:

Figure 5.11: Noise Checking Process.

To insure the pulses are not generated form noise, an algorithm is used to check the

waveform of the pulse.

// ISRvoid myInterrupt(void)

{

delay(10);

if (digitalRead(COUNTER_PIN)) // Insure there is a pulse

{

delay(10);

if (digitalRead(COUNTER_PIN)) // Reinsure there is a pulse

pulse++; // Increment counter

printf("Pulse Count = %d\n",pulse); // Display Pulse Count

}

Figure 5.12: Noise Checking Code.


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5.5.2 Interoperability

Parameters of the meter can be defined or modified using the header files sharedAMI.hand

sharedTCP.heasily to adapt with different digital meters vendors. Also the software of the

meter can be remotely updated too using an SSH session. An SSH server runs on the

Raspberry Pi allows the utility to connect to the meter at any time, which saves time to

market (TTM)and make the infrastructure more reliable.

5.6 USER'S SOFTWARE

The user at home can read and visualize the consumption of the electric energy, as well as to

read the current bill calculated by the Utility.

Figure 5.13: User's Side of the System.

The Raspberry pi was programmed to act as a webserver using the Apache2 Server and

connect to a Local Area Network (LAN) using the 802.11 (WLAN) adaptor attached to the

Raspberry Pi kit. The kit connects to the router at home and starts listening for connections

on port 80 (HTTP).


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The energy is logged in a file and saved in the Raspberry Pi, and the web server reads this

data and plots it on a web page that can be accessed by the home user using any web browser

by entering the IP Address of the meter on the home network.

Figure 5.14: Meter's Webpage.

The graph is interactive and can be adjusted to visualize the required period of consumption

and to locate Peak Times.

5.7 SECURITY

Advanced Metering Infrastructures (AMI) introduces communication between meters and

utility allowing information about consumption, outages, and electricity rates to be shared

reliably and efficiently. However, this opens new opportunities for attackers to interfere with

the network and compromise utilities' assets or steal customers' private information.


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Some of the key objectives for the attackers are energy frauds and communication threats

(e.g. eavesdropping) which considered very viral to the utility.

In this project we dealt with one widely common fraud, which is the unpaid bill fraud.

Some people will try to defraud the utility by not paying the bill and still can consume

energy. In our project, we used some algorithms to detect the possibility of unpaid bill fraud.

A sensor is used in the algorithm to accomplish this objective, and its located on the other

side of the main relay to check for a line voltage.

If a line voltage was detected and the main relay status was supposed to be open (the bill is

not paid), the meter sets a flag in the packet and sends it to the utility.

Figure 5.15: Unpaid Bill Fraud.


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CHAPTER 6: CONCLUSION


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6.1 WORK, PROBLEMS AND LESSONS

At first, we designed and tried to build the whole smart meter and PLC modem using ICs, but

we faced the problem of high shipping costs and customs taxes. Also, we didnt find the

required ICs or a substitute in the stores, so we had to look into other alternatives. We

searched the local market for Digital meters and PLC adaptors, and we managed to find

some.

For the software part, we had to learn about socket programming since we werent familiar

with them, for both C++ and VB.NET languages.

We started designing and testing each part of the system, beginning with the Raspberry Pi kit

since most of the work relies on it. We had to read the whole API of the Raspberry Pi to

achieve our goal. Then we wrote the codes for metering and communicating with the server

using sockets. After that, we successfully designed the circuits for relays using Multisim,

built, and tested the circuits for controlling both relays, the main relay and dispensable relay.

The Utility and User software was the last thing we worked on, with the need to read about

the related languages (VB.NET and Javascript).

Some of the products we found werent documented, so we had to search for similar products

and read their Manuals, and conclude how our products work.

We realized that no matter what topic we choose, problems will just get in the way, even if

we try to avoid them. We decided to face the problems and try to solve them. Hopefully, we

managed to find solutions for most of the problems.


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6.2 FUTURE PROPOSALS

6.2.1 Communication threats

To stop attackers from eavesdropping on the network or manipulate the data transferred

between hosts, a suitable encryption method must be used. The most convenient way to

protect the network is to use cryptographic protocols to provide security to the network.

Protocols used in IP networks are Transport Layer Security(TLS) and the older version

Secure Sockets Layer(SSL).

Figure 6.1: TCP/IP Stack Including Security.

They both rely on asymmetric cryptography (Public-key cryptography) to exchange

a symmetric key. This key is then used to encrypt data sent between the parties. This assures

confidentiality, and message authentication codes for message integrity. The sending

computer encrypts the data with a symmetric key, and then encrypts the symmetric key with

the public key of the receiving computer. The receiving computer uses its private key to

decode the symmetric key. It then uses the symmetric key to decode the data. This type of


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cryptography is more secure than symmetric cryptography that only uses on symmetric key to

encode and decode data because eavesdroppers cannot extract the private keys from direct

listening to the network.

Figure 6.2: Public Key Concept.

Using TLS as a security layer in the stack helps to protect the infrastructure from various

numbers of attacks and has many benefits: Strong authentication, integrity, and message

privacy, Interoperability, Algorithm flexibility, and Ease of deployment and use.

6.2.2 Power lines communication simulation

Power lines have been used as a communication channel for a long time, and it started with

low data rates (


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Figure 6.3: A Two-Port Network Model.

1=

2(

) +

2sinh(

)

1 = 2 1 sinh() + 2cosh() = ( +)( +)

= + +Where:

: Resistance per unit length : Inductance per unit length: Capacitance per unit length : Conductance per unit lengthThis leads to:

=() sinh()1 sinh() cosh()

By finding those parameters for and desired power lines, and using the right software, we can

simulate the modulation technique and determine what the best technique to be chosen is.


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6.2.3 Deployment of additional nodes

To make the infrastructure more reliable, we can introduce new nodes between the Smart

Meters and the Utility, called the Control Nodes, Located at the medium voltage/low voltage

transformer. These nodes can collect data from the Meters with more reliability and accuracy.

This allows utilities to add new functionalities efficiently.

Figure 6.4: Distribution of Control Nodes.


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1- Arduino, Arduuino Uno,0TUhttp://arduino.ccU0T,0TUhttp://arduino.cc/en/Main/arduinoBoardUnoU0T.

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3- Canadian Electricity Association, THE SMART GRID.

4- Cisco Internet Business Solutions Group, Smart Grid, November 2008.

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2007.

7- GENERAL ELECTRIC, Intellix SM110 Single Phase Electricity Meter - Residential

Application, March 2010.

8- Gordon Henderson, Gordon's

Projects,0TU

https://projects.drogon.netU0T

,0TU

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pi/wiringpi/functionsU0T

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9- International Electrotechnical Commission, IEC 62053-31 International Standard, 1998.

10- Microsoft, Dynamic Plotting of Graph Using

VB.NET, 0TUhttp://msdn.microsoft.comU0T, 0TUhttp://code.msdn.microsoft.com/windowsdesktop/Dyna

mic-Plotting-Of-Graph-573eef2fU0T.

11- National Energy Technology Laboratory, Advanced metering infrastructure, February

2008.
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June 2010.

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.

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http://en.wikipedia.orgU0T

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.

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,last updated

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.

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2014,0TU

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advanced metering infrastructure over power line communication

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