Smart Meter Messages

Many commands can be sent to Smart Meters and many alerts received back. All of these are sent through a very secure closed network.

Security

Security has been considered very carefully for Smart Meters. The communications network is not part of the internet, it is a closed network only accessible to parties with the right security keys and physical connections. Additionally there is no central database containing customers' information, the information is only stored on the Smart Meters and sent through DCC onto Suppliers and other parties who have a right to that data and where the customer has given them permission. The customer information inside messages is encrypted and only the receiving party can look at the data, the DCC cannot view the data. The parties receiving the data undergo a rigorous security assessment at the beginning and then have regular security audits.

The UK Product Security and Telecommunications Infrastructure (PSTI) Bill (2021) did not cover Smart Meters as they are already covered by robust regulation.

The National Cyber Security Centre has an excellent document explaining how the security works in relatively simple English.

End to End Security Model

Distribution Network

As well as Suppliers getting information from smart meters the Distribution Network Operators (DNOs), who look after the cables in the ground, will also get information. They can use this information to detect when cables might get too hot, the voltage drops in an area (known as a brownout) and when the power cuts out. The detailed information of performance over time can be used to help plan reinforcement of the network as demand increases.

Meter Alerts

Smart Meters can send information about the meter's environment and status as well as meter readings. This information can be used to diagnose meter faults, detect theft and security issues. There are some 250 events which can be sent in this way, suppliers and distributors will monitor these alerts, and take action at the appropriate point. For example a memory alert may mean the meter is faulty, whereas a reverse flow alert could mean that someone has reversed the meter in order steal energy.

Alerts add a high volume of messages to the communications flows, for example in April 2022 some 897 million messages were sent and received in total.

Controlling Smart Meters

Many different commands can be sent to Smart Meters. Some are to do with customer configuration such as prices, some are for maintaining the meter and others for security; only particular commands can be used by particular users. The user groups are defined as follows:

  • Import Supplier
  • Export Supplier
  • Gas Supplier
  • Registered Supplier Agent
  • Electricity Distributor
  • Gas Transporter
  • Other User.

The commands have been standardised so that meter manufacturers and operators can follow a common operational process, however, many manufacturers have added some additional commands of their own if they thought them to be useful.

There is a high level of security around these commands. The more important commands are sent back to the sending company by DCC for a final check before being sent on to the meter.

The list of standard commands below are for devices such as meters and communication hubs, and have been taken from the Draft Version 1.1 of the DCC User Interface Specification (DUIS) dated 16th December 2015 and published on 17th December 2015.

  • Update Import Tariff (Primary Element)
  • Update Import Tariff (Secondary Element)
  • Update Price (Primary Element)
  • Update Price (Secondary Element)
  • Update Meter Balance
  • Update Payment Mode
  • Reset Tariff Block Counter Matrix
  • Update Prepay Configuration
  • Top Up Device
  • Update Debt
  • Activate Emergency Credit
  • Display Message
  • Restrict Access for Change of Tenancy
  • Clear Event Log
  • Update Supplier Name
  • Disable Privacy PIN
  • Read Instantaneous Import Registers
  • Read Instantaneous Import TOU Matrices
  • Read Instantaneous Import TOU With Blocks Matrices
  • Read Instantaneous Import Block Counters
  • Read Instantaneous Export Registers
  • Read Instantaneous Prepay Values
  • Retrieve Change Of Mode / Tariff Triggered Billing Data Log
  • Retrieve Billing Calendar Triggered Billing Data Log
  • Retrieve Billing Data Log (Payment Based Debt Payments)
  • Retrieve Billing Data Log (Prepayment Credits)
  • Retrieve Import Daily Read Log
  • Retrieve Export Daily Read Log
  • Read Active Import Profile Data
  • Read Reactive Import Profile Data
  • Read Export Profile Data
  • Read Network Data
  • Read Tariff (Primary Element)
  • Read Tariff (Secondary Element)
  • Read Maximum Demand Import Registers
  • Read Maximum Demand Export Registers
  • Read Prepayment Configuration
  • Read Prepayment Daily Read Log
  • Read Load Limit Data
  • Read Active Power Import
  • Retrieve Daily Consumption Log
  • Read Meter Balance
  • Create Schedule
  • Read Schedule
  • Delete Schedule
  • Read Device Configuration (Voltage)
  • Read Device Configuration (Randomisation)
  • Read Device Configuration (Billing Calendar)
  • Read Device Configuration (Identity Exc MPxN)
  • Read Device Configuration (Instantaneous Power Thresholds)
  • Read Device Configuration (MPxN)
  • Read Device Configuration (Gas)
  • Read Device Configuration (Payment Mode)
  • Update Device Configuration (Load Limiting General Settings)
  • Update Device Configuration (Load Limiting Counter Reset)
  • Update Device Configuration (Voltage)
  • Update Device Configuration (Gas Conversion)
  • Update Device Configuration (Gas Flow)
  • Update Device Configuration (Billing Calendar)
  • Synchronise Clock
  • Update Device Configuration (Instantaneous Power Threshold)
  • Read Event Or Security Log
  • Update Device Configuration (Auxiliary Load Control Description)
  • Update Device Configuration (Auxiliary Load Control Scheduler)
  • Update Security Credentials (KRP)
  • Update Security Credentials (Device)
  • Issue Security Credentials
  • Set Maximum Demand Configurable Time Period
  • Reset Maximum Demand Registers
  • Set Device Configuration (Import MPxN)
  • Set Device Configuration (Export MPAN)
  • Request Handover of DCC Controlled Device
  • Configure Alert Behaviour
  • Update Security Credentials (CoS)
  • Retrieve Device Security Credentials (KRP)
  • Retrieve Device Security Credentials (Device)
  • Set Electricity Supply Tamper State
  • Enable Supply
  • Disable Supply
  • Arm Supply
  • Read Supply Status
  • Activate Auxiliary Load
  • Deactivate Auxiliary Load
  • Read Auxiliary Load Switch Data
  • Reset Auxiliary Load
  • Add Auxiliary Load to Boost Button
  • Remove Auxiliary Load from Boost Button
  • Read Boost Button Details
  • Set Randomised Offset Limit
  • Commission Device
  • Read Inventory
  • Decommission Device
  • Update Inventory
  • Service Opt Out
  • Service Opt In
  • Join Service (Critical)
  • Join Service (Non-Critical)
  • Unjoin Service (Critical)
  • Unjoin Service (Non-Critical)
  • Read Device Log
  • Update HAN Device Log
  • Restore HAN Device Log
  • Restore Gas Proxy Function Device Log
  • Return Local Command Response
  • Communications Hub Status Update - Install Success
  • Communications Hub Status Update - Install No SM WAN
  • Communications Hub Status Update - Fault Return
  • Communications Hub Status Update - No Fault Return
  • Request Customer Identification Number
  • Update Firmware
  • Read Firmware Version
  • Activate Firmware
  • Request WAN Matrix
  • Device Pre-notification
  • Record Network Data (Gas).

There are also a small number of messages from DCC rather than from the meters:

  • Power Outage Event
  • Device Status Change Event
  • DSP Schedule Removal
  • Command Failure
  • Firmware Distribution Failure
  • Update HAN Device Log Result
  • Change of Supplier
  • Device Log Restored
  • PPMID Alert.
(Page updated: 2022-05-07)

Questions & Answers


How often is data pulled from the meter?
Suppliers will try to contact your Smart Meter once a day to retrieve alarms and alerts. Meter readings will also be collected based on your agreement to have them recorded at monthly, daily or 30 minute intervals. (Updated: 2022-01-15)

Can my supply be turned off remotely?
Smart meters have the facility to remotely disconnect and reconnect both the electricity and gas supply. However, most suppliers seem to have decided it is too dangerous to remotely disconnect or reconnect, as in the case of disconnection they cannot always be sure that the customer isn't relying on a supply for serious health reasons and in the case of reconnection the customer may have left a cooker on for example. (Updated: 2015-01-23)

How do I top-up my smart meter PAYG if the mobile network is down?
Normally your PAYG (Pay As You Go) top-up will be sent automatically to the smart meter, however, if the communications link through the mobile network is not available then this cannot happen.
Firstly you can use the emergency credit that most suppliers offer. If that runs out you can enter the long authorisation number that you received when you paid for the credit into the meter or IHD (In Home Display) to apply your credit. This very difficult to do on the meter so use the IHD if you can. (Updated: 2019-10-21)

Are Smart Meters safe from hackers?
All smart meters in Britain have to conform to the same strict security standards, and go through testing against the Commercial Product Assurance (CPA) Security Characteristics by an approved laboratory.
The security system consists of many layers and has been design by Government Communications Headquarters (GCHQ). The National Cyber Security Centre (NCSC) is involved in ongoing reviews.
Smart meters use their own bespoke wireless connection to communicate with suppliers. This wireless connection has been built to be extremely secure, and is encrypted to prevent hackers being able to attack electricity supplies.
There are also monitoring systems in the background known as "Anomaly Detection" which look for unusual patterns of data across the communications network.
So they're not connected to the internet and only hold information on your energy consumption. Not only are smart meters hard to hack, there would be no point doing it anyway. (Updated: 2021-04-23)

How do Smart Meters send data?
The communications hub or comms hub sitting immediately onto top of your electricity meter is responsible for receiving and sending all data. This data can be meter readings, commands or alerts.
The comms hub uses the Home Area Network (HAN) to talk to the electricity, gas and IHD (In Home Display) devices. To save battery power the gas meter communicates only every half-hour and so the comms hub stores a copy of the gas meter data for querying when required. This copy is known as the gas mirror or Gas Proxy (GPF).
The comms hub uses the Wide Area Network (WAN) to talk to the company responsible for collecting the data and passing it on to other businesses such as suppliers; for the latest SMETS2 meters this company will be the DCC (Data Communications Company) which the government has set up especially for this role.
Depending on the Communications Service Provider, which varies by areas of the UK, the radio technology can change depending on what works best in a local area. Sometimes your comms hub will communicate directly with DCC and sometimes it will talk through other comms hubs around you to reach a particular comms hub which has direct communications with DCC. This form of communications looks like a mesh when you draw out the possible links between meters and is therefore known as a Mesh network. (Updated: 2020-11-07)

How much data is stored on a Smart Meter?
The SMETS2 specification requires the following data to be recorded and stored.
Half-hourly electricity data:
  • 13 months of consumption (Active Energy Import)
  • 3 months of active energy exported
  • 3 months of reactive energy imported
  • 3 months of reactive energy exported.
Gas data:
  • 3 months of half-hourly consumption
  • 13 months of monthly consumption.
(Updated: 2020-11-07)

Do Smart Meters measure voltage?
Yes, Smart Meters provide a record of voltage. This is of great interest to the Distribution Network Operators (DNOs) as they are responsible for setting the voltage on the network by adjusting the taps on transformers. The voltage on the network is more difficult than ever to control due to varying local generation.
UK Power Networks carried out a project on the Use of smart meter information for network planning and operation which included voltage.
Also see this document from Western Power Distribution giving their Smart Meter Strategy. (Updated: 2021-05-03)

Can smart meters be upgraded?
Smart meters can have a firmware upgrade just like your computer or mobile phone. The upgrade will be used to fix faults and add new functionality and should be carried out in the background with little impact on the customer. Indeed this feature is being used to allow SMETS1 meters to be upgraded for the SMETS2 systems; this will allow them all to interoperate. (Updated: 2019-10-21)

Why is two way communications important?
Smart meters send meter reading and event information to suppliers. Supplier can send product and payment details to the meter when you want to change your product or payment terms. Additionally this two way communications supports Pay As You Go for energy. (Updated: 2018-05-05)

What is dithering?
When a Smart Meter loses power and powers up it sends an alert message to suppliers and network operators to let them know. If a large area had lost power and thus a large number of meters were to send these messages at once it would put a heavy load on the communications network. To prevent this the meters "dither", that is to say they all wait a short random period before sending those first messages thus avoiding the simultaneous peak. For the first two years (to September 2018) the dithering period was up to 2 minutes. After that a decision will be made on whether to set it to the default 5 minutes. (Updated: 2016-02-16)

How often will my IHD be updated with data from my meters?
Your IHD (In Home Display) will be updated by your electricity meter about every 10 seconds and by your gas meter about every 30 minutes. The gas meter updates less often in order to preserve its battery life which in normal use is expected to be at least 10-15 years. (Updated: 2020-10-23)

Do I require a broadband connection or wi-fi in my home to be able to use a smart meter?
Smart meters don't need a broadband connection or wi-fi in your home as they use either the GSM (Global System for Mobile communications) mobile networks just like your mobile phone, or use a local mesh communications network (DCC only) to hop from meter to meter until a link to the GSM mobile network is found. (Updated: 2018-07-01)

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