Electronic energy meters have fostered their way into the market the last decade replacing conventional electromechanical meters. This has led to increased accuracy and features, reduced cost and size, and an opportunity to get smart. Energy measurement in its purest form, is just a mathematical sum of products of voltage and current. Just like any other math operation, this can easily be accomplished digitally using a micro-computer. To lower cost, one would choose the simplest form of these micro-computers; the microcontroller.Texas Instruments has a rich set of high performance devices to address this specific application space with the MSP430 family of microcontrollers. MSP430 family has set aside a broad portfolio of devices to support mono-phase to poly-phase energy measurements.
Energy conservation has been in people’s radar the last few years and measures to address this has been the primary goal for most law makers. Energy conservation in the electricity market in my opinion needs very less regulation. Each consumer, be it a business owner or a home owner, can easily conserve by adhering to some simple energy saving rules.
For example, in a home, energy can be conserved by turning off lights or appliances when not in use. However, each appliance will not have the same energy saving, and certain appliances cannot be turned off, instead can be made more efficient, such as an air-conditioner. It is my firm belief that every individual will help in energy conservation if they are made aware of their consumption (in some cases wastage) via energy consumption profiles.
An energy consumption profile is a summary of the energy usage of various appliances in a home or a business. It details the exact usage of each appliance with updates happening at regular intervals. This can be made available via sub-meters embedded in any appliance or stand-alone. A sub-meter is a compact electricity meter that can be used inside a home with an appliance to view its consumption on a display. It is not installed by the utility company and is wholly owned by a home owner for his personal use. I would prefer the stand-alone option, so existing home owners can still use them without having to change to compliant appliances.
A smart meter is any meter that can communicate; the communication can be with other smart meters, concentrator (host computer) or the utility meter. The sub-meters installed with wireless transceivers form nodes to form a simple home area network (HAN). The HAN will now help in consolidating the energy usage and report to a host (PC or an intelligent display) that will update the consumption profile. A home owner can easily monitor this and control appliances to save energy. Modifications to the air conditioner thermostat can also be done to reduce overall energy consumed having looked at the energy profile. MSP430 microcontrollers lead the industry with extremely low-power consumption, which helps in cheaper, simpler and robust sub-meters. A point worthy of mention here is, a meter gets bigger and expensive if its self energy consumption is higher. In addition these microcontrollers easily interface to low power RF transceivers from Texas Instruments. Moreover, the HAN does not have to be long range and is usually operated using the 2.4 GHz band. This concludes the discussion on energy saving setup at a home or business.
The energy consumption profile can now be transmitted to the utility meter, which is also a smart meter. Since the meter is outside the home, the range required is much higher and sub-1GHz transceivers can be used. In China 470 MHz band has been opened specifically for wireless transmission among utility meters. However, in the US 902-928 MHz, 433 MHz or the 315 MHz can be used for this purpose. Once the energy profile is available to the utility meter, it can be sent to the utility company for a variety of benefits. The profile will assist utility companies to assess the typical energy consumption of a home or a business over an entire day. Better yet, they can access this for an entire community or sections of any city. This will help them with efficient distribution of energy during peak demand and provide incentives for low energy usage during this time. This is also called multi-tariff in metering terminology.
The MSP430 microcontrollers with its powerful integrated analog signal chain, provides some very good accuracy numbers (< ±0.2%) for energy measurement. Accuracy is important to both the utility company and the consumer. For example in the absence of good accuracies (> ±2%), the home owner stands to pay > 2% (when error is positive) more on his bill, or the utilities stand to lose > 2% (when error is negative).
TI’s Low Power RF transceivers from Texas Instruments accommodate all the possible bands for wireless transmission with its wide variety of devices. In addition, the MSP430 easily interfaces to all of them to form a total solution to smart metering thereby helping in both energy saving and energy conservation.
In this blog I have tried to highlight the importance of energy conservation and reducing energy costs from the point of both an average consumer and the utility company. If any of you have any questions feel free to comment.
Kripa Venkat
MSP430 Applications Engineer
Texas Instruments
Migrated from tinergy.net and posted by TI communicators who follow the ever evolving world of power and energy. The team maintained tinergy.net and blogged about TI’s new innovation announcements and power activities.
