Smart Grid Needs Smart Meter SoC, Part 1

The traditional power utility's electrical network moves vast amounts of energy from power stations to a large number of customers (consumers). In essence, a power plant consists of a centralized control, the mechanism for one-way flows of power, and passive networks.

This classic view of the power grid is passing into history. On the energy net, there will be not only more lines, circuit breakers, and transformers, but also electronics, information, and communication protocols. The smart meter provides the way to get information regarding load usage into the communications channel. From there, the information is sent back to the power utilities' generation and control centers.

One of the main drivers pushing this development is the goal that by 2020, greenhouse gas emissions will have been reduced by 20% compared to 1990 levels, energy efficiency will increase by 20%, and 20% of electricity will come from from renewable sources. So the smart grids are the future of electronics and communications. Here we provide a tutorial for the design and the implementation of the smart meter portion of the smart grid.

The trend for smart grid systems management in the industry is to integrate a complete smart-meter System-on-Chip (SoC) that combines precision metering with a flexible and programmable processing. In addition, there should be Power Line Communication (PLC) subsystems to safely and effectively couple data onto the power line. With care, the power line can carry data along with power. Finally, provisions should be in place for advanced security methods for the transfer of data. With care, it should be possible to put all of this functionality in a single device.

The goal of a smart meter system is real-time control and adaptability of the grid, integration of decentralized generation from renewable energy sources, and support for multiple communication standards. These standards have to be secured by physical routers and by software firewalls such as, for example, the encryption of the communication. The information about energy flow in the smart grid cells has to be reliable and secure to avoid energy wastage and guarantee an end-to-end optimized management of the energy.

The SoC for smart grid is a device that integrates a programmable PLC modem. It contains a high-performance application core and metrology functions (see Figure 1).

Figure 1

SoC Smart Meter architecture

SoC Smart Meter architecture

The typical architecture is composed of a primary digital core , a secondary digital core and a metrology sub-system .

In part 2, we will examine each of these sections to see what they do and consider accuracy requirements.

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9 comments on “Smart Grid Needs Smart Meter SoC, Part 1

  1. etnapowers
    November 25, 2013

    In the smart Soc I find very interesting the presence of two cores , one is deputed to the metering functions and the other for data elaboration and interfacing with the smart grid. Both of these processors have to be reliable and communicate effectively in a safe way.

  2. Davidled
    November 25, 2013

    I wonder that it is possible to get the one unit memory using one processor instead of two separated memories. In the task perspective, it is very beneficial to get two separated tasks in the two processors. However, it seems like more current consumption from two processors is drawn than one processor. MY understanding is that in the bottom line, customer pays the energy bill including the Smart meter. Or does energy company pay the bill of Smart meter separately?

  3. etnapowers
    November 25, 2013

    @Daej: you're right two cores have an higher consumption than a unique core solution. The user pays only the service that he utilizes , the core deputed to smart metering on the grid is disposed by the company.

  4. samicksha
    November 26, 2013

    If we are using smart meter SoC for multiple communication interface (URAT/ SPI), i guess need of memory partiotioning and protection becomes more relevant here.

  5. etnapowers
    November 26, 2013

    @samicksha, you're right, memory managing and protection are really relevant, these items will be deal in details in the part 2 of this blog.

  6. Vishal Prajapati
    November 26, 2013

    @Paolo, I don't understand why two cores are there? I think timing function can be integrated using RTC block also. I am not sure I might be wrong also.

  7. etnapowers
    November 26, 2013

    @ vishal: Your question makes sense to me, the answer is that two cores are needed to ensure the local metering function and the interface with the power line. The core dedicated to measuring purpose has to be placed in some physical points of the net that might be different respect the core dedicated to the interface to the powerline. That's the reason for why two cores are needed.

  8. Netcrawl
    November 26, 2013

    Not just for multiple communication interfaces, there's also some sensors-lots of them , whose primarey job is to provide real-time data crucial in smart grid operations.

  9. yalanand
    November 30, 2013

    @Paolo, By introducing  the  electronics into electrical transmission , we can easily achieve the controllability . Through this there will be significant savings in power while switching and transmitting. But on the other side it will add extra circuitry to every end on transmission and the questions may arise how long these meters  last.

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