EECE 501 Final Year Project Final Report

EECE 501 Final Year Project Final Report Power line Data transmission over power lines and applications Jad Allam Camille Eid Joseph Raad 200300105...
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EECE 501 Final Year Project Final Report

Power line

Data transmission over power lines and applications Jad Allam Camille Eid Joseph Raad

200300105 200300308 200300301

[email protected] [email protected] [email protected]

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Abstract “Data transmission over power lines” a technology that sends data through existing electric cables alongside electrical current, is set to turn the largest existing network in the world, the electricity distribution grid, into a data transmission network. We study the applicability of data transmission over power lines (DTOPL) techniques to home automation. We conducted this study after noticing the lack of gathered information on the subject, and this caused by the relatively new research and development in this area. In our project, we will present both a broad overview and a technical reference on data transmission over power lines with a comprehensive presentation dealing with the different aspects of this technology. We designed a home automation system using DTOPL and in a first phase, run the performance analysis of the used power line technology, and secondly, build the system that best represents the real life application dealing with the security issues.

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Acknowledgements We wish to express our deep gratitude to Dr. Sami Karaki for his continuous support and ideas that helped persevere in our project. We would like also to thank Mr. Francis Raveneau, business development manager in Ariane Controls Corporation, Quebec, Canada, for the technical support that he provided us with about the company’s products. We would like also to thank the electrical and computer engineering department for funding a large part of our project.

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Table of contents: 1 Introduction.................................................................................................................... 8 1.1 General overview ...................................................................................................... 8 1.2 Project specifications .............................................................................................. 10 2 Review of DTOPL technologies .................................................................................. 12 2.1 Applications of Data transmission over Power lines .............................................. 12 2.1.1 Low voltage or in-house .................................................................................. 12 2.1.2 Medium Voltage and Low Voltage.................................................................. 13 2.2 Comparison and evaluation of different protocols.................................................. 14 2.2.1 X-10 ................................................................................................................. 14 2.2.2 CeBus technology ............................................................................................ 16 2.2.3 LonWorks technology...................................................................................... 18 2.3 Standards and regulations ....................................................................................... 20 2.3.1 CENELEC........................................................................................................ 20 2.3.2 FCC .................................................................................................................. 21 2.3.3 IEEE................................................................................................................. 21 2.3.4 IEC ................................................................................................................... 21 2.4 Challenges in the power line home network........................................................... 22 2.4.1 Noise and disturbance characteristics .............................................................. 22 2.4.2 Impedance and transfer function...................................................................... 27 2.4.3 Signal attenuation............................................................................................. 28 2.4.4 Security Issues and Problems on the line......................................................... 28 2.5 Comparison with other technologies ...................................................................... 31 2.5.1 X-10 ................................................................................................................. 31 2.5.2 CEBus .............................................................................................................. 33 2.5.3 LonWorks ........................................................................................................ 37 3 Design of the system..................................................................................................... 40 3.1 Description of the project block diagrams .............................................................. 40 3.1.1 Choice of the chip and diagram of the system................................................. 40 3.1.2 Ariane AC Transceiver .................................................................................... 43 3.1.3 Microcontroller ................................................................................................ 47 3.1.4 PC..................................................................................................................... 48 3.1.5 Relay ................................................................................................................ 49 3.1.6 Controlled system ............................................................................................ 50 3.2 Project application .................................................................................................. 51 3.2.1 Performance analysis ....................................................................................... 51 3.2.2 Encryption........................................................................................................ 54 3.3 Time and cost planning of Spring semester............................................................ 56 3.3.1 Time table division .......................................................................................... 56 3.3.2 Task Description .............................................................................................. 57 3.3.3 Tentative projected cost ................................................................................... 58 4 Implementation of the design...................................................................................... 59 4.1 DTOPL Management Software .............................................................................. 59 4.1.1 Overview.......................................................................................................... 59 4.1.2 Implementation of the software objectives ...................................................... 59 4.1.3 Detailed description of the communication protocol....................................... 63 4.1.4 Snapshots from the software interface............................................................. 70 4

4.2 Home automation on PIC........................................................................................ 75 4.2.1 The circuit ........................................................................................................ 75 4.2.2 The program..................................................................................................... 76 4.2.3 Cases ................................................................................................................ 78 5 Evaluation of the design .............................................................................................. 79 5.1 Results of Ariane modules performance after testing phase................................... 79 5.1.1 Objectives ........................................................................................................ 79 5.1.2 Procedure ......................................................................................................... 79 5.1.3 Graphical results .............................................................................................. 81 5.1.4 Conclusion ....................................................................................................... 87 5.2 Problems encountered............................................................................................. 87 5.2.1 Software ........................................................................................................... 87 5.2.2 Hardware.......................................................................................................... 90 5.3 Design constraints................................................................................................... 91 6 Rooms for Design Development: AMR...................................................................... 92 6.1 Automatic Meter Reading overview....................................................................... 92 6.2 AMR Diagram description...................................................................................... 92 7 Conclusion .................................................................................................................... 95 8 References..................................................................................................................... 96

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List of figures: Figure 1: Representation of the X-10 signal ..................................................................... 15 Figure 2: Two packets of the X-10 protocol..................................................................... 16 Figure 3: Table of the different channels that support the LonTalk protocol................... 19 Figure 4: Comparison table from Xilinx........................................................................... 19 Figure 5: Measured amplitude and duration characteristics of noise [11]........................ 26 Figure 6: Measured impedance models of common electric apparatus [11] .................... 27 Figure 7: Simplified diagram of the final circuit .............................................................. 41 Figure 8: AC Transceiver diagram ................................................................................... 43 Figure 9: Coupling unit of the model [15] ........................................................................ 44 Figure 10: Dataflow diagram ............................................................................................ 46 Figure 11: Relay diagram.................................................................................................. 50 Figure 12: Column graph showing the reliability of Ariane [14] ..................................... 52 Figure 13: Table describing the sources of noise in the Ariane test [14] ......................... 53 Figure 14: Steps for the encryption process...................................................................... 55 Figure 15: Data encryption diagram ................................................................................. 55 Figure 16: Tasks planned for the Spring semester............................................................ 56 Figure 17: Time span for each task of the previous table ................................................. 56 Figure 18: Product list and Costs ...................................................................................... 58 Figure 19: Flow diagram of the protocol implementation in the software ....................... 61 Figure 20: Web Interface .................................................................................................. 63 Figure 21: General Packet Format .................................................................................... 64 Figure 22: Single Data Packet........................................................................................... 65 Figure 23: Multi-Packet Data Start ................................................................................... 65 Figure 24: Multi-Packet Data Continuation...................................................................... 66 Figure 25: Multi-Packet Data End .................................................................................... 66 Figure 26: Ping.................................................................................................................. 66 Figure 27: Ping Reply ....................................................................................................... 66 Figure 28: Command ON.................................................................................................. 67 Figure 29: Command OFF ................................................................................................ 67 Figure 30: Advertise ON Power ....................................................................................... 67 Figure 31: Advertise OFF Power...................................................................................... 67

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Figure 32: Assign Address................................................................................................ 68 Figure 33: Advertise Address ........................................................................................... 68 Figure 34: Assign Keys..................................................................................................... 68 Figure 35: Advertise Keys ................................................................................................ 69 Figure 36: Microcontroller/Relays.................................................................................... 69 Figure 37: Graphical User Interface ................................................................................. 70 Figure 38: Example of a “single data” packet being transmitted first encrypted (Hello) and then in plain text (Goodbye) .............................................................................. 71 Figure 39: Example of a “multi-packet data” being transmitted (abcdefghijklmnopqrstuvwxyz) ................................................................................ 72 Figure 40: Example of home automation opening relays 2, 3 and 4. ............................... 73 Figure 41: Example of ping/reply showing that a device is connected. ........................... 74 Figure 42: Picture of the controlling circuit...................................................................... 75 Figure 43: Table of possible cases for the controlling circuit........................................... 78 Figure 44: Diagram of the experiments procedure ........................................................... 79 Figure 45: Transmission phase from PC1......................................................................... 80 Figure 46: Reception phase on PC2.................................................................................. 81 Figure 47: Different load noise sources ............................................................................ 85 Figure 48: Type 2 experiment results ............................................................................... 86 Figure 49: Example of a form submission where R0R1R2R3=0101 ............................... 89 Figure 50: Diagram showing the AMR system ................................................................ 92

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1 Introduction For the past years, power lines have been used for the transmission of electricity; but nowadays with the emergence of modem networking technologies and the need for information spreading, data transmission over power lines has seen a really big growth. The technologies already used for spreading information such as telephone wiring, Ethernet cabling, fiber optic and wireless have each its limitations in cost and reliability. In this project we are going to discuss the advantages of using power lines as a communication medium and the wide range of applications that this technology can provide, in addition to the implementation of a home automation system using the data transmission over power lines.

1.1 General overview Home automation is the solution for the future household. Today’s technology has evolved houses to be as smart as simulation games on PCs and PS2s. Smart houses can be literally programmed to execute pre-defined and real time instructions on a specific time of the day, the week, or even the month. The garden sparklers can turn on in the morning automatically; the music can be dimmed in all around the house to provide a comfortable environment for work, study, or even entertainment. Moreover, a smart house is a safe house. Safety can be considered both from the inside and the outside. Safety is first to make the house theoretically impossible to rob, and practically more difficult only. Different schemes could be adopted in order to attain this privilege. One could implement a safe perimeter by installing cameras, infrared sensors, or just

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traditional safety equipment. All these instruments require electricity for operation. The second type of safety is inside the house. The most important issue is to monitor the living persons and animals inside the house, especially children. Baby monitors are nowadays the easiest way to keep an ear at the baby while performing everyday tasks. A pacemaker in the heart of an elderly person can suddenly turn off and lead to a heart attack without anyone near that person to hear his call for help. An automatic feeding system for cats could be installed inside the kitchen and will save the house residents from the burden of “remembering to feed the cat”!! All three of these equipments need electricity to function. When using Data Transmission Over Power Lines (or DTOPL), any household can afford having a small scale smart house, and most importantly a safe one. No need to run new wires inside the walls and under the floor in order to get this network. Regular, standard power lines are the best alternative to be able to control, from a single computer, a set of equipments and tools by sending commands to them, either on a pre-defined schedule, or simply when getting a response from these instruments.

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1.2 Project specifications Our project consists of sending data and commands over regular power lines in order to implement home automation. First of all, we had to make a choice whether to build and implement a new protocol or use an existing one in order to achieve this task. Having seen the amount of alternatives, we finally decided that building our own would be reinventing the wheel and would not be as performant as one that has been tested, designed and commercialized by world wide companies. Hence, we shifted the largest weight of our project on the application and its benefits and on improving wellestablished protocols rather than starting from scratch. In order to achieve that, we had to review the available emerging technologies, compare them and choose the one that would suit our purposes the best. Having achieved the literature review, our choice fell upon Ariane Controls. In fact, among the candidate protocols, Ariane offered the fastest, the most reliable and the most flexible of them all.

Once the protocol choice has been made, we started designing our project, keeping several objectives in mind: •

Low design price



Simplicity in design



Efficiency and reliability



General purpose (be adaptable to several applications, configurations and environments)



Security



Ergonomic and aesthetical design

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The design mainly consists, at the transmitter side, of a central command unit (PC) that will provide an interface through which a user can issue orders that will be modulated by a power line modem. Then, the modulated message is transported over a power line used as a channel. At the receiver side, another modem will demodulate the message and send it to a local command unit that, based on the message, will issue orders to appliances and equipments. However, in our strive for improvement, we pushed the design further by adding several functionalities such as security, Web access, real time network discovery and real time status update.

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2 Review of DTOPL technologies 2.1 Applications of Data transmission over Power lines The applications of DTOPL are very wide and we can divide them into two categories: the Medium Voltage or access technology mainly used by the utility authority and which is behind the scope of our project, the Low Voltage or in home which cover the area of sending data over power lines within the consumer’s side and extends to all the electrical outlets within the home.

2.1.1 Low voltage or in-house 2.1.1.1 Home automation Many years ago control of appliances in the home used to call for the establishment of new cable wiring in the home. With the DTOPL technology automation of a building can be done using power lines only. Hence we can control home appliances, light switches, wall outlets, thermostats, Heat Ventilation and Air Conditioning systems (HVAC), sensors, alarm and security. One of our project goals is to implement the home automation. 2.1.1.2 Street lights monitoring The use of DTOPL to monitor street lights leads to big savings in the electricity bill of the government by introducing selective dimming or selective turn-off features. This application can increase energy savings by 25%.

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2.1.1.3 Low cost inter-device peer-to-peer networking Power lines may be used to create a network that links devices together on the power grid. Since such a network makes use of the existing infrastructure, installation time and cost are virtually non-existent. Also since every outlet or junction box becomes a point where a device may be connected, the device can be moved around numerous times. An example of such a network can be to replace the RS232 wiring required to set audio and video inputs on various systems in a house or a building.

2.1.2 Medium Voltage and Low Voltage 2.1.2.1 Utility a) Automatic Meter Reading is a technology that uses the power line to send information to the utility directly. Meters can be linked to concentrators to allow suppliers to have remote access to each individual meter, to read or write information such as rates, prepaid amounts, current and cumulative counts, tampering detection, etc. Meters and/or concentrators can also be used along with AC Remote LCD devices to replicate and distribute their information to one or more points located anywhere on the electrical network b) Load shedding: this is done when we need to reduce power given to loads when we have peak demands hours. As an example incandescent lights, with the help a of load control circuit will receive less power when the utility notices that the demand for electricity is at its peak in certain periods.

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2.1.2.2 Broadband data transmission This developing technology which is at its testing level (Italy, USA) nowadays enables broadband internet to be provided to your home using the electrical grid. This feature is behind the scope of our project however we will give a brief overview of what this technology is about: An example of a company developing this technology is ABB Medium Voltage Power Solution [1]. This system certified for use up to 24 KV provides data transfer rates of up to 10 Mbps and hence challenging the xDSL and the broadband cable technology. The main problem in this technology is the connection between the MV and the LV grid which is done using optical fibers, copper pairs or wireless.

2.2 Comparison and evaluation of different protocols Research and study in the technology domain supporting DTOPL led to the emergence of different protocols describing the modulation scheme used, the data transmission rate, the limitations, the drawbacks, the relative cost and the target applications.

2.2.1 X-10 It is the most ancient communication protocol used in home networking since 1978 [2] developed by X-10 US Corporation. It is used to allow compatible devices to communicate with each other over 110V AC wiring.

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2.2.1.1 Protocol description X-10 simply provides the technical specifications of how a device should place a signal onto the power line. The X-10 technology transmits binary data using the amplitude modulation technique. In order to differentiate the data symbols the carrier uses the zerovoltage crossing point of the 60 Hz on the negative or positive cycle. Hence for synchronization, the presence of a 120 kHz signal burst at the zero crossing indicates the transmission of a binary one, whilst the absence of the 120 kHz signal indicates a binary zero. (fig.)

Figure 1: Representation of the X-10 signal

X-10 contains a detailed addressing scheme to prevent device clash. Devices contain two addresses - a house (dwelling) address, and then an individual device address. A typical X-10 transmission would include a start code, house address, device address, and then function code (such as ON, OFF, etc.). The X-10 system is limited in that it does not easily provide for two-way communications, and is very slow, although adequate for simple home automation tasks.

Every bit requires a full 60 Hertz cycle and thus the X-10 transmission rate is limited to only 60 bps. Usually a complete X-10 command consists of two packets with a 3-cycle 15

gap between each packet. Each packet contains two identical messages of 11 bits (or 11 cycles) each. A complete X-10 command consumes 47 cycles that yield a transmission time of about 0.8.

Figure 2: Two packets of the X-10 protocol

2.2.1.2 Disadvantages The X-10 technology would not fit our project design for the main fact that it has limited potential in speed and intelligence terms. Its low data rate and undeveloped functionality permit to use the X-10 technology in limited applications. In addition to its unreliability of amplitude modulation and error correction, X-10 operates on 110V AC, which is a major drawback for its use.

2.2.2 CeBus technology CEBus, or Consumer Electronics Bus [3], a standard proposed by the Electronic Industries Association, is based on the concept of Local Area Networks (LAN’s), for the home. CEBus based products consist mainly of two components: a transceiver which

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implements spread spectrum technology along with a controller to run the protocol. The given protocol standards are for radio frequency, twisted pair, power line communication and a number of other home networking methods. The CEBus DTOPL standard specifies that a binary digit is represented by how long a frequency burst is applied to the channel. For example, a binary ‘1’ is represented by a 100 microsecond burst, whilst a binary ‘0’ is represented by a 200 microsecond burst. Consequently, the CEBus transmission rate varies with how many ‘0’ characters, and how many ‘1’ characters are transmitted. The CEBus standard specifies a language of object oriented controls including commands for volume up/down, temperature up one degree, etc. Due to the high noise level of power line channels, data should be transmitted via short frames, which is assured by the use of the spread spectrum technology. CEBus protocol uses a Carrier Sense Multiple Access/Collision Detection and Resolution (CSMA/CDCR) protocol to avoid data collisions. CEBus is a commercially owned protocol, and thus attracts registration fees.

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2.2.3 LonWorks technology This technology has been developed by Echelon Corporation [4]. It is essentially structured as an automatic control system that consists of sensors, actuators, application programs, communication networks, human-machine interface and network management tools.

LonWorks (Local Operation Networks) technology is an important new solution for control networks developed by Echelon ® Corporation. A control network is any group of devices working in a peer-to-peer fashion to monitor the different components cited above. In some ways, a LONWORKS control network resembles LAN. It can control and link factory conveyor belts, product inventory, and distribution systems for optimum efficiency and flexibility. Smart office buildings can turn lights on and off, open and lock doors, start and stop elevators, and connect all functions to a central security system. In the same manner, homeowners can program a vast array of products and conveniences, from sprinkler systems to VCRs, with a touch tone phone from any remote location.

The LonTalk communications protocol is a layered, packet-based, serial peer-to-peer communications protocol. This protocol is designed for the requirements of control systems, rather than data processing systems. Also, this protocol is media-independent, which allows the system to communicate over any physical transport media. LonTalk has been approved as an open industry standard by the American National Standards Institue (ANSI)-EIA 709.1. [5]

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Figure 3: Table of the different channels that support the LonTalk protocol

Power lines are a possible medium that LonWorks devices could be attached to. The data rate will then be 5 kbps and, obviously, there is no limit to the number of devices that could be connected to the system. Some real life applications of LonWorks are automated supermarket pricing, avionics instrument integration, circuit board diagnostics, electronic locks, intelligent industrial I/O irrigation, management, lighting control, power supply management, and research experiment monitoring.

Figure 4: Comparison table from Xilinx

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2.3 Standards and regulations When using the powerline as a channel certain standards and regulations must be followed in order to avoid interference between the frequencies transmitted with any other frequencies already existing. Hence the bandwidth in the DTOPL environment is not limited by physical capabilities of the line. Rather, regulatory authorities in the developed countries limit the available bandwidth in order to prevent radio interference, other devices interference or military bandwidth interference. We will discuss in the following section the limiting standards CENELEC, FCC, IEEE and IEC governing data transmission over power lines.

2.3.1 CENELEC For Western Europe CENELEC’s standard EN50065 [6] “Low voltage mains signaling” gives regulations on key parameters such as frequency range, signal power and so on. The standard allows signals to operate in the frequency band 3- 148.5kHz, avoiding interference with ripple control systems at the lower boundary, and interference with long wave (LW) and medium wave (MW) radio broadcasts by posting the upper boundary. CENELEC then divide this band into further categories:

The band from 3-95 kHz, or A-Band, is allocated for electrical utility use, for such things as automated meter reading and customer load control. The range from 95-148.5 kHz, comprising the B, C, and D bands is reserved for end-user applications. These three bands are primarily differentiated by regulations in protocols for each band. B band, from 95-125 kHz requires no use of access protocol for establishing communications. This band is designed for use in applications such as baby-monitors and intercoms. The C

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band from 125 to 140 KHz is mainly used for intra-building computer communication. Finally the D band from 140 to 148.5 KHz is limited to energy customers' providers.

Lastly, EN50065 specifies such things as maximum signal attenuation allowed due to multiple, filter specifications for carrier removal, and specifies the maximum transmitted power for transmission over power lines should not exceed 500 mW.

2.3.2 FCC For North America the Federal Communications Commission (FCC) [7] regulates transmitted power and bandwidth. The frequency range in this standard is from 100 to 450 KHz which is higher than the CENELEC. Moreover Part 15 of the American FCC’s rule allows transmission over power lines outside the AM frequency band (535 to 1705 KHz).

2.3.3 IEEE The Institute of Electrical and Electronics Engineers [8] have published a set of recommendations and standards pertaining to the power line communication available at the reference: http:://standards.ieee.org/catalog/olis/psystcomm.html.

2.3.4 IEC The International Electrotechnical Commission (IEC) [9] has standardized the distribution line communications through technical committee #57 working group 9. In this standard, IEC TC57/WG9 uses frequencies below 150 KHz.

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2.4 Challenges in the power line home network Power lines are a hostile environment that makes the accurate propagation of communication signals difficult and are not designed for data transmission use. Noise levels are often excessive, and cable attenuation at the frequencies of interest is often very large. Important channel parameters such as impedance and attenuation are time varying in unpredictable ways. Following is a detailed description of the challenges encountered in the power line channel.

2.4.1 Noise and disturbance characteristics Noise on electrical power networks on the Medium Voltage side is usually caused by corona discharge, lightning, power factor correction banks and circuit breaker operation. In our project we are dealing with a low voltage network, and hence much of this noise is filtered by medium/low voltage transformers, therefore the most common interference in low voltage domestic networks can be attributed to the various household devices and office equipment connected to the network. We can generally classify the disturbances into two categories and the noise into four categories. 2.4.1.1 Disturbances Waveshape disturbances These include: - Over and under voltages, both persistent (>2 seconds) or surges (