By Jerry Ramie, KI6LGY
acrel Product Page
Q) What is an electric or power meter?
A) In electric-utility parlance, it is the kw-hour meter between your mains and the load center and measures your electric power usage.
Q) What is a smart meter? How does it differ from a conventional electric or power meter?
A) A smart meter is like a conventional power meter in that it also measures your electric power usage, but it has other capabilities, such as the ability to be read remotely without sending a person out to your meter. See Figure 1.
Q) What is the smart grid?
A) The modernization of the electric power grid, often called the "smart grid" by its proponents, is an important goal. Efforts such as the Advanced Metering Infrastructure (AMI), Automated Meter Reading (AMR) and the other phases of intelligent grid management are all part of a smarter grid. Having better control of the power grid will improve its reliability and efficiency and, as applications are developed for end users, point-of-use monitoring and control of power usage and generation will benefit utilities by reducing peak loads and benefit consumers by providing a way to save on their energy costs. See the ARRL Web site for more information at: http://www.arrl.org/electric-utility-communications-applications-and-smart-grid-technologies
Q) Where are smart meters being deployed at the present time?
A) Smart meters are being deployed all over the United States and in many other countries.
Q) In the US, under what part of the FCC rules do smart meters operate?
A) Part 15, just like most other consumer and household electronic devices. On most frequencies, Part 15 permits only very low-power operation -- a few nanowatts in some cases. Under the Part 15 rules, certain bands have provisions for higher-power operation. Because these bands are also used by Industrial, Scientific and Medical devices, these bands are often called the ISM bands. That does not change the status of the smart meters, though; they operate exclusively under Part 15 of the rules, not Part 18 like actual ISM devices. For more information on Part 15 and Part-15 devices, see http://www.arrl.org/part-15-radio-frequency-devices. Other nations have similar rules.
Q) Can Amateurs expect interference from smart meters? Do they have potential RFI generating circuitry, such as digital circuitry?
A) In general, Amateurs should not expect interference from smart meters on most Amateur bands. And yes, smart meters do have digital electronics inside of them that can act and emit RF, much like an ordinary personal computer. There is, however, a greater potential for interference on some cases, particularly when a smart meter system intentionally transmits data on a so-called ISM (Industrial, Scientific and Medical) band that is shared with the Amateur service.
Q) Do you mean smart meters contain an intentional RF transmitter?
A) Sometimes. When a smart meter contains an RF transmitter:
The frequency of operation is typically in the 902 MHz and 2.4 GHz bands.
Power output is typically 1 watt in the 902 MHz band and much less in the 2.4 GHz band.
The intended range of a transmitter in a smart meter is typically very localized.
While the utility-side radio needs to reach a neighborhood concentrator, typically mounted on a nearby pole, smart meters can also mesh through other smart meters to communicate with the concentrator. (using five hops or less)
See Figure 2.
The smart meter only communicates when it is commanded to do so, typically several times a day.
The smart meter&#;s transmitter operates under Part 15 of the FCC rules.
Q) I recently upgraded my electric service from 100 to 200 A. My old electric meter had gears and a mechanical readout. The new one however, is all electronic. It has an LCD readout and some sort of radio transmitter in it. I&#;m happy to report that I&#;ve had no interference issues with it but wonder&#; Is it possible I already have a smart meter?
A) Not necessarily. Your new meter may simply have remote reading capability. This means a meter reader can ping your meter for a reading from the street. The meter then transmits the reading by radio. Efficiency is improved since he or she no longer has to enter your property. Smart meter technology, on the other hand, implies two-way communication with the meter. Smart meters also have memory and data processing capability.
Q) Do smart meters use some form of carrier current technology or BPL?
A) First, let&#;s define &#;carrier current.&#; A carrier-current device uses power lines, in-building or utility-controlled to intentionally conduct RF signals. Carrier-current devices are also governed by a carrier-current section in the Part 15 rules.
In some areas, smart meters and/or the smart grid may use carrier-current technology. Each electric utility chooses the architecture they want to deploy, sometimes under the direct or indirect influence of decisions made by state or local regulators. Under Part 15 rules&#;
If a carrier-current device is used to transmit digital information, and it operates from 1.7 to 80 MHz, it is operating under the BPL rules in Part 15.
If it operates on other spectrum, it operates under the carrier-current rules in Part 15.
If it used exclusively on the high-voltage lines feeding substations, carrier-current devices can operate under the power-line-carrier (PLC) section of Part 15.
So far, in the US, smart-meters have not used BPL. Some of the protocols for home-area-networks that may be associated with smart meters and smart-grid technology may use BPL, but it is likely that the systems will use the HomePlug technology. HomePlug does not use the Amateur bands, so it has little potential to interfere with Amateur Radio. (Other spectrum could experience interference from HomePlug devices.)
For information on BPL, see http://www.arrl.org/broadband-over-powerline-bpl.
If and when a smart meter uses carrier current technology:
The frequency range used by PLC meters use Cenelec Band B @ 63 kHz for the consumer side.
Some smart meters also use BPL for the utility side.
It is also possible to have BPL on the home wiring in a home-area-network (HAN) tied to the smart-meter and smart grid.
The intended range of the carrier current communications is typically very localized.
Just like a concentrator in the case of radio communications, the receiver is located on a nearby pole.
The smart meter&#;s transmitter typically operates multiple times per day, but only when the utility &#;pings&#; the meter.
Q) How does a smart meter receive commands from the utility, or does it?
A) All smart meters are not the same. Utilities can send commands to a smart meter by both radio and carrier current communications, depending on the type of meter being used. In California, for example, the utilities presently deploying smart meters control the meters using 902-928 MHz FHSS radio. The intended range and frequencies used for sending commands to a smart meter can also vary from utility to utility.
Q) Can Amateur Radio cause interference to a smart meter? What are the rules regarding such interference?
A) Yes, amateur operation nearby can desensitize some meters so they can&#;t hear commands. The smart meter is operating under Part 15 of the rules, which stipulates that Part 15 devices are not protected from interference from licensed radio services, such as Amateur Radio.
Q) What protection does Amateur Radio have from interference to and from a smart meter?
A) In the US, smart meters in residential areas are required to meet absolute emissions limits for unintentional emitters and/or carrier-current devices and the transmit power limits for intentional emitters as specified in Part 15 rules. Licensed radio services such as Amateur Radio also receive unconditional protection from harmful interference from all Part 15 devices, including smart meters. In addition, Part 15 devices, such as smart meters, receive no protection from interference resulting from licensed radio services.
Note: Although the frequencies typically used by smart meters are also ISM bands, which are covered by Part 18 of the FCC rules, they actually operate under Part 15. This is an important distinction. If a smart meter were operating under Part 18, the Amateur Service would have to accept any harmful interference such a meter might generate. Part 18 devices however, are prohibited from using RF for communications purposes. Since smart meters transmit data, they can&#;t legally operate as Part 18 devices.
For reference purposes, the following table shows the overlap between the Amateur and ISM bands typically used by smart meters:
Amateur Band
ISM Band*
Notes
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902 &#; 928 MHz
902 &#; 928 MHz
33 cm Amateur Band
&#; MHz
&#; MHz
&#; .5 MHz
The Amateur band is broken into two segments. The ISM band extends past the Amateur band at the upper end.
*Note: The higher-power provisions in Part 15 typically use the ISM bands.
Q) What about other types of utilities, such as water and gas? I understand they are also converting to new meters with the capability to communicate by means of RF. Do the same smart meter rules still apply, at least in terms of my concerns about RFI?
A) For the most part &#; yes. Just like "smart" electricity meters, these water and gas meters often use radio energy to communicate. When they do, they most likely operate in an ISM band under Part 15.
These are extremely low-power devices that spend most of their lives turned off waiting for a contact with the utility radio network. Water & gas meters usually operate on 2.4GHz using a very narrow-bandwidth implementation of the ZigBee Smart Energy Profile.
Since gas and water meters are not connected to a source of electrical energy, they both use "scavenger" (impeller) techniques to generate small amounts of electrical power to keep the on-board battery topped off. This approach provides a battery life expectancy of greater than 10 years.
In many cases, the meter is pinged or timed to contact any nearby "smart" electric meter. The smart electric meter can then store their readings and send them upstream to the utility billing system. Although it's usually communicating with the same customer's smart electric meter, it doesn't have to be. The system is "meshed" and can pass data along as required. The &#;smart meter&#; in this case will often have two radios under the glass - one for the consumer side at 2.4GHz and one for the utility side at 902-928MHz.
These two communication "medias" (utility and consumer) are different in each utility jurisdiction. You may be able to learn more about the specific technology being used by your utility from their Web site. For a more thorough discussion of the different utility communications medias and their relative impacts on the amateur service, please see the article on electric utility communications on the ARRL website at: www.arrl.org/electric-utility-communications-applications-and-smart-grid-technologies
The electric meter at your house measures the amount of electricity you use in kilowatt-hours (kWh). One kWh is equal to using 100 watts of electricity for 10 hours. Your monthly electric bill is based on the amount of energy you use. (A customer who uses 2,000 kWh will have a higher bill than one who uses 1,000 kWh.)
Smart meters are uploading usage information daily. Southern Maryland Electric Cooperative (SMECO) uses meter data to bill you monthly. The time between billings may vary from 27 to 34 days if a scheduled bill date falls on a weekend or holiday. The date the meter was read and the number of days in each billing period are printed on your bill.
Smart meters are able to communicate. They automatically send information such as outage alerts and energy usage for meter readings.
Smart meters are one step in the process of implementing technological improvements to our electric system.
AMI technology pays for itself through operational savings. With standard meters, whenever someone moves into or out of a house, SMECO has to send a truck to turn the meter on or off. Sometimes we have to make two trips in the same day. With smart meters, we can perform those tasks remotely, saving time, gas, and labor costs. Smart meters will also allow SMECO to respond more quickly to outages and that means your power will be restored faster.
Your smart meter data is used for billing purposes. Log into Account Manager to view your energy use. You&#;ll be able to compare it to weather data and billing data. SMECO provides energy use and billing data to help you manage your energy use and control your electric bill.
SMECO uses smart meters that automatically send information such as outage alerts and energy usage data. You can read your meter to help you keep track of your kWh usage, or you can log into Account Manager to track your energy usage and more.
The displays on the smart meters cycle through seven screens, which change every few seconds. Watch our smart meter video further down this page for more information on reading your meter.
The first screen in the sequence simply verifies that the display is working properly.
The second screen is a marker for the next screen, which shows the amount of electricity used as measured in kilowatt-hours (kWh). For most residential customers, the third screen shows all they need to know.
Some customers have solar panels or other means of generating their own electricity. The fourth screen is a marker for the upcoming screen, which displays the amount of excess energy produced by the customer&#;s solar panels. SMECO&#;s meter doesn&#;t measure how much energy you produced and used during the month.
The sixth screen is a marker for the upcoming screen, which shows electricity demand. Demand is the maximum amount of electricity that you consume at a given time. The seventh screen displays the amount of demand as measured in kilowatts (kW). Commercial customers are billed for their demand.
SMECO&#;s policy, in accordance with applicable law, is to protect the confidentiality of smart meter energy use data. SMECO&#;s confidentiality policy applies to data that are under SMECO&#;s custody, whether the data reside under SMECO&#;s control or under the control of a SMECO-approved third party.
SMECO&#;s smart meters store and communicate customers&#; electric energy use data, which include the amount of energy used and the time interval during which the energy was used. This policy covers this smart meter energy use data. SMECO uses the energy use data to bill customers.
SMECO will not sell a customer&#;s energy use data to a third party. In some instances, SMECO may be required to disclose individual data pursuant to regulation or law.
All customers currently or previously receiving electric distribution or supply service from SMECO, whose usage data is in SMECO&#;s custody, are covered by this policy. This policy applies to all smart meter energy use data maintained by SMECO, electronic or printed, stored on any medium. Energy use data that are not specific to the customer, such as combined or aggregated data, are not covered by this policy. SMECO discloses energy use data not covered under this policy in accordance with laws, regulations, Maryland Public Service Commission orders, and SMECO&#;s Commission-approved tariffs.
SMECO is required by law to observe certain prohibitions regarding the disclosure of individual customer data. Customers&#; smart meter energy use data will only be collected, processed, retained, or disclosed for legitimate SMECO utility-related business reasons.
Customers may contact SMECO to request their own energy use data. In addition, SMECO may provide energy use data with customer consent to a third party, primarily those providing energy-related products or services, taking into account the nature and frequency of the customer&#;s request.
SMECO is committed to protecting customer information, and that commitment continues as smart meters are employed and technology evolves. Personally identifiable information, such as name, address, account number, social security number, or credit and payment information, is not transmitted to or from the meter.
SMECO protects smart meter energy use data by using an access-controlled private data network. SMECO employees and their contractors may not access, remove, disclose or use smart meter energy use data (other than for legitimate company business) nor may employees or contractors assist others in such access, removal, disclosure, or use. All employees and contractors who have access to smart meter energy use data are required to maintain the confidentiality of that information during and after employment or engagement with SMECO.
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