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  • Power Line Communication in Energy Markets Page 1 of 15

    Published in Industrial Control DesignLine (http://www.eetimes.com) August 2011

    POWER LINE COMMUNICATION IN ENERGY MARKETS By Antonio De Lima Fernandes, and Pooja Dave, Product Marketing Engineer, Cypress Semiconductor Corp.

    What is Power Line Communication? Power Line Communication (PLC) is a communication technology which enables sending data over existing power cables. This means that, with just power cables running to an electronic device (for example) one can both power it up and at the same time control/retrieve data from it in a half-duplex manner.

    PLC Market: Overview

    Segments

    For the purpose of understanding, PLC can be broadly viewed as

    1. Narrowband PLC

    2. Broadband PLC

    Narrowband PLC works at lower frequencies (3-500 kHz), lower data rates (up to 100s of kbps) and has longer range (up to several kilometers) which can be extended using repeaters. Broadband PLC works at higher frequencies (1.8-250 MHz), high data rates (up to 100s of Mbps) and is used in shorter range applications. Recently, narrowband Power Line Communication has been receiving widespread attention due to its applications in the Smart Grid. Another application that narrowband PLC has been used in is smart energy generation, particularly in micro-inverters for solar panels.

    Broadband PLC, in contrast, is mainly found acceptance as a last-mile solution for internet distribution and home networking. With its high data rates and no additional wiring, broadband PLC is seen as an exciting and effective technology for multimedia distribution within homes. This optimism in the markets is reflected by the recent acquisitions of Intellon by Atheros, Coppergate by Sigma, DS2 by Marvell and finally Gigle by Broadcom, all in the Home Area Networking (HAN) segment.

    There is another way to classify Power Line Communication and that is as

    PLC over AC lines PLC over DC lines Whilst most companies are currently geared towards providing AC-PLC solutions, PLC in DC lines also has applications. Two such applications are PLC over the DC-bus in distributed energy generation, and PLC in transportation (electronic controls in airplanes, automobiles and trains). This reduces wiring complexity, weight and ultimately cost of communications inside vehicles. However, in this article, we will be dealing mostly with narrowband PLC over AC lines.

    Competition

    The narrowband PLC market is seeing healthy competition, with a large number of PLC suppliers joining the fray.

    Cypress Semiconductor Echelon ST Microelectronics Yitran Texas Instruments Maxim Semitech Semiconductor Ariane Controls ADD Semiconductor Microchip

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    The some of the companies in the broadband PLC segment are

    Atheros Sigma Marvell Broadcom Lantiq Maxim Plugtek

    PLC Technology: How does it work? PLC is like any other communication technology in which a sender modulates the data to be sent, injects it on to medium, and the receiver de-modulates this data to read it. The major difference is that PLC does not need extra cabling - it re-uses existing wiring. Considering the pervasiveness of power lines, this means with PLC, virtually all line-powered devices can be controlled or monitored!

    When discussing communication technology, it is often useful to refer to the 7-layer OSI model. Some PLC chips can implement only the Physical Layer of the OSI model, whilst some chips integrate all 7 layers of the OSI model. One could use a Digital Signal Processor (DSP) with a pure software realization of the MAC and an external PHY circuit, or an optimized System-on-Chip (SoC) solution, which includes the complete PLC MAC and PHY. The Cypress CY8CPLCXX series is an example of the latter, with a ready-to-use Physical and Network layer, and a user-programmable application layer.

    Before moving on to the applications of PLC, let us first understand the various aspects of the Physical layer by viewing it as 3 segments on the basis of data rate.

    Table 1. PLC technology classification on the basis of data rate

    Low Data Rate Medium Data Rate High Data Rate Data Rate 0-10kbps 10kbps-1Mbps >1Mbps

    Modulation BPSK, FSK, SFSK,

    QAM PSK+OFDM PSK+OFDM

    Standards IEC 61334, ANSI/EIA 709.1, .2, UPB

    PRIME, G3, P1901.2 G.hn, IEEE 1901

    Frequency range Upto 500kHz frequency

    Upto 500kHz In MHz

    Applications Contol and Command Control and command, Voice

    Broadband over powerline, home

    networking

    Modulation Schemes

    A variety of modulation schemes can be used in PLC. Some of these are Orthogonal Frequency Division Multiplexing (OFDM), Binary Phase Shift Keying (BPSK), Frequency Shift Keying (FSK), Spread-FSK (S-FSK) and proprietary schemes too (for example Differential Code Shift Keying (DCSK) from Yitran). In the table below, BPSK, FSK, SFSK and OFDM are compared on the basis of two important criteria bandwidth efficiency and complexity (cost).

    Table 2. Comparison of Modulation Schemes

    Modulation Scheme Bandwidth efficiency Complexity

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    BPSK Medium Low

    FSK Medium Low

    SFSK Low Medium

    OFDM High High

    OFDM in particular offers high data rate but requires computational horsepower to churn out Fast Fourier Transforms (FFT) and Inverse-FFT (IFFT) as required by the scheme. On the other hand, BPSK, FSK are robust, simple but offer lower data rates. The current trend is to move towards OFDM with PSK modulation (G3 and probably P1901.2). Such heavy computation will require DSP capability, whereas FSK, PSK and SFSK can be accomplished by a microcontroller.

    Standards

    Various standards have been developed in order to ensure reliable communications and inter-operability, especially for the smart grid and home networking. Examples of such standards are

    Table 3. Specifications of narrowband PLC standards

    Standard Technology Frequency band Bit rate (kbps)

    G3-PLC OFDM 36-90.6kHz 5.6-45

    PRIME OFDM 42-89kHz 21.4-128.6

    IEEE P1901.2 OFDM 9-500kHz Coming Soon

    ANSI/EIA 709.1,.2 BPSK 86, 131kHz 3.6-5.4

    KNX S-FSK 125-140kHz 1.2

    IEC61334 S-FSK CENELEC-A 2.4

    These, along with the organizations that govern them like CENELEC, FCC, ARIB, Homeplug Power Alliance specify ranges for operation of PLC. If a worldwide standard for PLC were to be established, this would have a positive impact on adoption of PLC. So far, the G3-PLC standard is touted as the most robust scheme available, and the IEEE 1901.2 working group is committed to developing a universally acceptable standard.

    Frequencies

    Different regions of the world have different frequency bands allocated to narrowband PLC. The table below summarizes the different frequencies available for narrowband PLC communication in the respective region.

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    Table 4. Narrowband PLC frequency ranges for various regions

    Region Regulatory Body

    Frequency Band

    Note

    Europe CENELEC 3-95kHz 95-125kHz 125-140kHz 140-148.5kHz

    A Energy providers B Reserved for users C Reserved for users, regulated CSMA access D Reserved for users

    Japan ARIB 10-450kHz China EPRI 3-90kHz

    3-500kHz Not Regulated

    USA FCC 10-490kHz

    Where

    CENELEC - European Committee for Electrotechnical Standardization. ARIB Association of Radio Industries & Businesses EPRI Electric Power Research Institute FCC Federal Communications Commission

    Applications Earlier, we saw that PLC is widely used in the Smart Grid and in micro-inverters. As the market gets familiar with this technology, PLC should see wider adoption in other applications like lighting (e.g. Traffic light control, LED dimming), industrial (eg. UPS communicating to a network device, irrigation control), machine-to-machine (eg. Vending machines, a hotels reception-to-room communication), telemetry (eg. Offshore oil rigs), transport (e.g. Electronics in cars, trains and airplanes) and indeed, applications of PLC are only limited by ones creativity. In this article, we will find out a little more about PLC in energy generation and conservation markets.

    Energy Generation and Consumption: Today, Smart Energy has become a much-publicized buzzword. It could describe anything from energy production, to efficient use of that energy. As we will shortly see, PLC plays a vital role in making our energy practices smart.

    PLC in Energy Generation

    Renewable energy is growing at a brisk rate, having showcased a growth of 35.2% in 2010. A bulk of this growth came from a near doubling of Photovoltaic (PV) installations around the world. Further contribution came from increase of installed wind energy capacity; for instance in 2010 China grew its installed capacity by 64%.

    In order for a Distributed Generation (DG) system to supply the grid power, its DC output must be converted by an inverter into clean, reliable AC power. Thus a typical DG system consists of the Energy production device (for e.g. the solar panel, the wind turbine, an electric vehicle), the inverter, the cabling and the communications. If we consider the specific case of solar power generation, until recently, most PV installations used central inverters or string inverters, in which case the performance of the system could be monitored with a few say, Ethernet connections to the inverters.

  • Power Line Communications in Energy Markets Page 5 of 15

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    Figure 1. Roof-top solar panel installation with micro-inverters

    Today, there is a growing trend towards micro-inverters and power optimizers. These function at the individual solar panel level, and most suppliers provide monitoring capability for each of these modules. This provides vital performance statistics over the lifetime of the solar panel, and this can be used to detect and pinpoint performance issues. To implement such monitoring capability, one could use wireless Zigbee, Wi-Fi, RF, and Bluetooth; or wired PLC, RS-485, RS-232, Ethernet amongst others. In the case of micro-inverters, the implementation of a wireless solution can be challenging because of

    Its line of sight requirement micro-inverters are generally located behind a solar panel More complicated installation EMI problems Alternatively, other wired technologies involve extra cabling and thus greater installation and maintenance costs. PLC can be both simpler and more economical.

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    MPPT DC-DC DC-AC

    ISLANDDETECT

    Solar Photovaltaic (PV)Array

    DC-DC conversion raises the incoming PV voltage; MPPT

    will adjust its output for greatest efficiency

    DC-AC conversion for feeding power into the home /

    grid

    Maximum power point tracker; Dynamically adjust the DC bus voltage of the solar array to its optimum

    value as sunlight and temperature conditions vary

    Communication interface between micro-inverter &

    central control unit (in home / office)

    Detect when power from the electric utility no longer

    present; micro-inverter stops supplying power to grid

    Home / Grid

    REG.CHECKS

    Regulatory checks (UL/IEEE/IEC requires that the inverter operates within

    certain parameters)

    EMIFilter

    AuxiliaryPowerSupply

    LCDDisplay

    and UserInterface

    PLC

    Figure 2. Block Diagram of a Micro-inverter

    Above we see the typical building blocks of a micro-inverter. The CY8CPLCxx chip, complete with PHY, network protocol and programmable application layer, has additional resources that allow for taking external sensor input. Thus vital parameters like temperature at each module, maximum power point, potential faults, and power generated can be monitored. Through the power line, these statistics can be viewed locally on an LCD display, or even remotely via the web. In case of faults, each micro-inverter can be switched off individually. Under-performing units can be repaired or replaced. Importantly, with PLC, installation and maintenance is simple and economical because of no additional sockets/wiring required - just plug and play. From the point of view of an equipment manufacturer, designing PLC into the system is straightforward because of Cypress certified and tested reference designs.

    PLC in Energy Consumption market It is estimated by 2020, Europe will have 80% coverage of smart meters and the rest of the world is expected soon to follow suit. PLC is the predominant communication method in Automatic Metering Infrastructure (AMI) and also is being rapidly adopted in other applications. In this section we will discuss the energy consumption market from two perspectives, namely

    1. Smart Grid AMI, Smart Appliances and V2G

    2. Other applications Two examples will be discussed here Data center power distribution and Lighting control.

    Smart Grid

    Mr. Carnegie, waiting for his flight at the San Francisco international airport, browses through his inbox on his smart phone, when he receives a mail from the local energy provider informing him about peak pricing coming into effect in the next four hours, back home in Dallas. He knows that his Air Conditioning will turn off automatically during this time. Knowing the electricity rates at this hour, he decides to check up on his solar panels by just a touch on his smart phone screen. While this may seem to be science fiction, smart grids, empowered by PLC solutions, are making it a reality.

    The Smart Grid is essentially modernization of the transmission and distribution aspects of the electrical grid. This intelligent power distribution infrastructure enables two-way communication between the consumers and the utility. The consumers use

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    home networks to communicate with their smart meter, which further communicates with the utility (Advanced Metering Infrastructure-AMI). The Smart Grid definition does not stop at energy utilization; supply of energy to the grid from Distributed Generation (DG) sources like solar and wind fall into the same category. The DG system also includes Vehicle-to-Grid (V2G) - bi-directional sharing of electricity between Electric Vehicles (EVs) and Plug-in Electric Hybrid Vehicles (PHEVs) and the electric power grid. In this article, we will talk about AMI, Smart Appliances and V2G.

    Concentrators

    SolarPanels

    WindTurbines

    CorporateOffices

    CallCenters

    MeteringDatabaseManagementCentre

    SmartMetering

    PowerLines

    GenerationandDistributionSubstations

    ElectricVehicle Office/Home

    Figure 3: The Smart Grid

    Advanced Metering Infrastructure:

    The whole measurement and collection system that includes meters at the customer site, communication networks between the customer and a service provider, such as an electric, gas, or water utility, and data reception and management systems, that make the information available to the service provider, are referred to as AMI.

    The Smart Meters transmit the collected data through commonly available fixed networks such as Power Line Communications (PLC), Fixed Radio Frequency (RF) networks, and public networks (e.g. landline, cellular, paging) which is aggregated by a concentrator, sent to the utility and then to a Meter Data Management System for data storage, analysis and billing (see Figure 3). Studies show that Narrowband PLC is best suited for AMI with over a 100 million NB-PLC devices installed to date.

    Utilities are investing billions of dollars in AMI systems. PLC solution for data transmission needs no new infrastructure, unlike wireless, as it uses the existing power cables. Power line carrier systems have long been a favorite at many utilities because it allows them to reliably move data over an infrastructure that they control. Utilities may also use public cellular as the backhaul for the AMI data due to its footprint, zero implementation cost and low monthly fee. But on many occasions they may not be able to provide 100 percent coverage of a utilitys entire customer base. Alternatively, using wireless networks, RF solutions or PLC for data transmission will solve this issue. Rural utilities or the utilities located at challenging locations (for e.g. mountainous terrains) which are ill-served by wireless will have a difficulty communicating with the consumers. Additionally,

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    wireless and RF solutions have reduced data rates in presence of interference like Bluetooth devices, cordless phones, concrete objects, hills and even trees. PLC can communicate to any location connected via the powerline and has no line-of-sight requirement for data transmission. One of the most important considerations, due to the volume of network traffic inherent to the smart grid network, is congestion mitigation. As compared to wireless solutions based on ZigBee or Wi-Fi, PLC-based AMI have a proven track record of being better suited to avoid network congestion in emergency situations. Another oft cited requirement is that of redundancy in the communication channel with the ubiquity of power lines, deploying a redundant channel becomes more economical.

    Various applications would include remote monitoring, outage management (which includes fault detection of MV equipment), Demand Response (i.e. managing customer consumption of electricity in response to grid supply conditions), island detection (i.e. ensuring that local grids are not being powered by the DG system when there is no power present from the electric grid) and fraud/theft detection.

    Figure 4: Advanced Metering Infrastructure

    Smart Appliances:

    A Home Area Network (HAN) is a communication-enabled home where all electrical appliances are connected in a mesh through Wireless, RF or PLC. Electrical appliances, today, are connected in a network with two-way communication enabled, with each other as well as the substation. These Smart Appliances allow automation and control from single or multiple access points.

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    $3,542

    $2,693

    $2,236

    $1,354

    $1,166

    $0 $1,000 $2,000 $3,000 $4,000

    ClothesWasher

    Refrigerator

    ClothesDryer

    Dishwasher

    Freezer

    SmartApplianceGlobalRevenue(2011)

    USMillions

    Figure 5: Smart Appliances Global Revenue

    In the chart above (Figure 5) you will observe the estimated revenues (US $M) in 2011 made by Smart Appliances (Source: Zpryme Research & Consulting) and is projected to grow with a CAGR of 49% from 2011 to 2015.This gives an insight to the potential that this industry holds. Talking about applications, PLC has made Load Control a reality in many EU Countries. Home appliances, like washing machine, dryer, dishwasher, oven and stove, refrigerator, freezer, air conditioner and water heater, talk to the Smart Meter, (Refer to previous section for details) which gathers information of peak pricing hours from the utility through PLC. The appliances can then switch OFF/ON according to the price variations. This is a win-win situation for the consumer who saves on the electricity bill, and the utility which can better manage peak demands. PLC also enables appliance monitoring and HVAC control leading to further energy awareness and savings.

    Home automation potentially focuses on the following applications:

    Lighting Appliance/Device Diagnostics and Monitoring Security Access AMI Home health monitoring

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    Figure 6: Cypress PLC in HAN

    In the figure above (Figure 6), the sensors on the appliance side are connected to the Monitor via the Power Line. Any changes on the appliance end will be reflected on the LCD Display which can be viewed and changed as required. Consumers will literally have control of their entire house at their fingertips.

    PLC is a considerably more effective in home networks. HAN being realized by Wireless/Zigbee, will need new infrastructure to be installed. Moreover, penetrating physical barriers like walls within one floor, or reaching out to different floors is a challenge for Wireless. Wireless networks often face performance issues, like mentioned in the previous section, due to RF interference caused by devices like microwave oven, cordless phones or even Bluetooth devices at home. PLC on the other hand can reach out to every node connected via the power line. It converts virtually every socket in ones home into an access point, in many ways incorporating the best of wired and wireless communication.

    Vehicle-to-Grid Communication:

    Plug in electric vehicles (BEVs and PHEVs) communicate with the power grid, both, to charge itself and to deliver electricity into the grid.

    Different versions of V2G would include a Fuel-cell vehicle, a battery powered vehicle or a solar vehicle. In all cases, the vehicle provides power to the grid at peak load conditions and charges itself at night, when the demand is low.

    A variety of data like vehicle identification, current battery status, maximum allowed charge current and number of phases, charging times (e.g. delayed charging start) and overall 'charged' electricity amount with associated costs is needs to be exchanged with the EVSE (Electric Vehicle Supply Equipment). PLC has a distinct advantage here because an unambiguous physical association between the vehicle and a specific EVSE can be established - this aids in authentication and security. This is clearly something that is not possible to accomplish with wireless solutions even if short range. PLC further connects the EVSE to the meter and the smart grid. This technology is still in its infancy with no existing standards but promises to be an exciting trend to watch out for in the next decade.

    Other Applications

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    In order to give readers a glimpse of the enormous potential of PLC in the energy consumption market, 2 applications will be dealt with in detail. PLC in data center power distribution networks, and PLC in Lighting.

    Smart Power in Data Centers:

    The Problem:

    With the rise of cloud computing and internet services, data centers and collocation facilities continue to show consistent double digit growth. Data center downtime is completely unacceptable due to loss of revenue and reputation that it causes. Such downtime is primarily caused by UPS battery failure, UPS overloading, and circuit breaker failure. Another critical concern for data centers is energy efficiency of devices because of rising unit electricity costs and additional cooling costs. Simultaneously, companies who outsource their computing requirements want access to all performance metrics of their systems including power at various levels. Adding communication between devices is a challenge, because wireless cannot work reliably in the data center environment whilst wired communication would exacerbate the problem of cable clutter.

    Network Devices

    Monitoring

    Figure 7. Monitoring the cloud

    Consider traditional power distribution architecture in a data centre a highly simplified diagram is shown below for the purpose of understanding:

    PSU 1UPS 2 PDU 2 Network

    device 2PSU 2

    PSU 1UPS 1 PDU 1 Network

    device 1PSU 2

    Redundant supplyLive supply

    OUT1

    OUT2

    OUT1

    OUT2

    AC MAINS

    Figure 8. Power distribution topology in a typical data center

    AC supply from the grid first flows through the Uninterruptible Power Supply (UPS), then the Power Distribution Unit (PDU), then converted to DC power at the Power Supply Unit (PSU) and then finally to a Server, Switch, Network storage device or in general, a network device. In such configurations with redundant power provisioning, UPS load rarely exceeds 30% of its rated capacity. This is largely because the power topology down-stream from a UPS is not clearly visible at the UPS it is difficult to trace which/how many Network Devices are connected to that UPS. Shown below is the typical efficiency curve for a UPS.

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    0%

    10%

    20%

    30%

    40%

    50%

    60%

    70%

    80%

    90%

    100%

    0% 20% 40% 60% 80% 100%

    Eff

    icie

    ncy

    Load (% of full load)

    Rapid drop of efficiency below 30% Nominal efficiency

    Typical range of operation of UPS

    Figure 9. UPS Efficiency versus Load

    In order to avoid costly downtime due to overloading, the data center would prefer to over-design the system operate the UPS at low loads, at the cost of energy efficiency. From the above curve, it is evident that the UPS is not working in its most efficient range.

    The solution:

    Now consider a PLC-enabled system as below. The UPS, PDU, PSU and Network devices can communicate with each other via PLC. Consequently, at every stage in the power distribution, the device will have a clear map of power topology downstream and upstream from it. For ex. UPS 1 knows that it provides power to PSU 1 of Network device 1 and 2. Now, since the devices connected to it are visible, their power requirements are known precisely, and hence the load of the UPS can be safely increased to an optimum level.

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    I2CPLCPowerEthernet/RS232

    PSU 1

    AC MAINS

    UPS 2 PDU 2 Network Device 2PSU 2

    PSU 1UPS 1 PDU 1 Network

    Device 1PSU 2

    OUT1

    OUT2

    OUT1

    OUT2

    Figure 10. PLC-enabled Power distribution topology in a data center

    Thanks to PLC, UPS overloading, battery failure and circuit breaker failure will be reduced, or diagnosed prior to downtime. Thus, introducing PLC in such power distribution architectures will not only increase efficiency of the system, but provide many other benefits including ease of diagnostics and redundancy in communication for mission critical data centers. And all this, without the messy wiring that data centers dread.

    LED Control: One of the predictions for the energy sector in the next decade is the gradual phasing out of incandescent bulbs and their replacement by LEDs. LEDs offer an advantage over both CFLs and incandescent bulbs in being fully dimmable, having a longer lifetime, being mercury free, and providing options for adjustable color temperature.

    The problem:

    Take for example, the case of street lighting. A city spends 30-40% of its budget on illuminating the city. The old system of street lighting makes no provision for dimming of lights, color temperature control or intelligent switching. Moreover, workers are hired for maintenance patrol i.e. Detecting and reporting failed street lights. Very often, street lights are repaired after complaints are lodged. Millions of dollars could be saved and millions of tons of carbon emissions could be reduced with minor adaption in the streetlight usage pattern.

    The solution:

    Now consider a street lighting system which is PLC enabled say, every LED street light has a PLC device mounted on it. This would allow for monitoring and control of each street light. The advantages of such a system are numerous.

    According to time, traffic, weather and other factors, the street lights can be turned off/dimmed as optimally as possible. This could generate energy and cost savings in excess of 40% - a huge number for any city. A corresponding reduction in carbon emissions is results thus helping cities comply with Kyoto protocol guidelines. Additionally, dimming will increase the lifespan of the LED lamps thus providing another benefit.

    Lamps which reach the end of their life cycle can be replaced before they fail, with reduced maintenance costs. Information of mortality cycle, energy consumption and other factors can be sent to the remote monitoring site and this

    used to diagnose problems.

    With the appropriate solution, color temperature of the streetlights can be dynamically adjusted providing better aesthetics and safety.

    Moreover, all this is done with no additional wiring, no need to dig up roads or build towers PLC is the most suitable and affordable solution for such an application.

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    Figure 11. Cypress' PLC solution for street lighting

    Above is a block diagram of such a PLC solution specifically tailored for High Brightness (HB) LED control. Cypress PLC Solution provides a Powerline optimized Network Protocol which enables individual lighting fixtures or groups of lighting fixtures to be controlled using the existing Powerline infrastructure. Combined with Cypress EZ-Color solution this can be used for intelligent dimming and timed turn-off of HB-LED fixtures.

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    Challenges PLC, of course has its challenges. Firstly, Power lines were not designed to carry data, and actually behave as low pass filters. Modeling the PL channel is difficult it is a very harsh and noisy transmission medium, frequency-selective, time-varying, and is impaired by colored background noise and impulsive noise. Thus maintaining signal integrity over power lines requires robust signaling techniques and hardware. Secondly, the structure of the grid differs across and within countries and the same applies for indoor wiring practices. There is no universal standard either for PLC or the grid; steps to ensure interoperability of devices need to be taken. Thirdly, questions are being raised today about the digital security of personal information that is sent over the power lines because these can be tapped into. Thus establishing privacy safeguards and equally important - convincing the public of these is another large-level issue that is being addressed. Lastly, PLC faces competition from other means of communication - both wired and wireless, and ultimately the choice of technology will be decided by a mix of cost, complexity and feasibility. Today, the major competing technologies to narrowband PLC are Zigbee, Wi-Fi, GPRS and RS-232.

    Conclusion In the above article, we introduced Power Line Communication, both as a technology and as a market. The various types of PLC, modulation schemes, standards, frequencies in use today were discussed. Finally, we presented the various applications of PLC in energy generation, the smart grid, data-center power distribution networks, and, in LED lighting. Finally, the challenges of PLC were briefly highlighted.

    We have seen how, in its current applications, PLC has added intelligence into previously dumb power networks. And this is just the tip of the iceberg. With the increased emphasis on developing PLC technology and standards, we can be confident that in the future, Power Line Communication will continue adding smartness to our lines.

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