MP085A Synchronisation of smart meter voltage measurement periods

Proposer Alan Creighton
Lead Analyst Bradley Baker
Date raised 12/09/2019
StageReport Phase
Implementation date 3 November 2022 (targeted)
Latest update On 18 January 2022 the Change Sub-Committee agreed that this modification proceeds to the Report Phase. SECAS will now issue the Modification Report Consultation. Responses are due by 8 February 2022.

What is the issue?

The expectation of Electricity Network Parties during the development of the smart meter technical specification was that the average Root Mean Square (RMS) voltage readings from smart meters would be measured across a consistent period. For example with the default being for an average to be made across a 30 minute period starting on the hour and again on the half hour. This is not an explicit requirement codified in Smart Metering Equipment Technical Specifications (SMETS) or Great Britain Companion Specification (GBCS).

Without voltage measurements being made in a consistent way, Electricity Network Parties must either:
i) make conservative, less efficient analysis assumptions to account for the lack of data alignment, or
ii) recreate synchronised data by downloading high granularity (for example minute resolution) data and calculating the required data.

Investigations during the Refinement Process found the issue affecting existing installed meters more complex than initially envisaged. This could result in a lengthy lead time for implementation where meter Manufacturers could potentially still produce Devices that do not commence average RMS voltage readings on the hour. Therefore, it has been agreed that there should be two separate solutions to address the issue;
• MP085A (this modification) – a Technical Specifications document change for meter Manufacturers to ensure newly manufactured Devices commence average RMS Voltage Measurement Period readings on the hour or half past the hour (whichever occurs first); and
• MP085B – a solution for meters that are currently installed.

What is the solution?

The Proposed Solution is to provide a consistent approach for all Electricity Smart Metering Equipment (ESME); ensuring that the Average RMS Voltage Measurement Period starts or resumes from a predictable point in time, allowing automatic realignment of a Device’s measurement periods with those of other ESMEs. This will allow DNOs to make full use of the Average RMS Voltage Profile Data Logs for remote comparison across all of their ESMEs.

As there are several situations that can lead to an Average RMS Voltage measurement being interrupted, e.g. due to a power interruption, reboot of the ESME, firmware activation, etc., a solution was needed that would allow the sampling of the Average RMS Voltage to recommence after an interruption in a way that would realign the measurement period to that of neighbouring ESMEs (an ESME in a similar location under the same DNO but at a difference premise). In the case of such an event or when starting up for the first time, the ESME should align the start of a reoccurring Average RMS Voltage Measurement Period sequence to the start of the current Coordinated Universal Time (UTC) day. The accumulation of RMS voltage values should then begin when the ESME reaches the start of the next period.

To align the measurement periods of multiple ESMEs it is expected that the length of the Average RMS Voltage Measurement Period be consistent across all of a given DNO’s ESMEs, as well as ensuring that the length of the period be a factor of 1800 seconds (30 minutes). This is to align with the default value an ESME is configured to prior to installation (GBCS defines this as 1800 seconds). This will also ensure that the sequence of measurement periods continues to align throughout the day, regardless of when an interruption to the measurement of Average RMS Voltage may occur.
The DNO is the only impacted Party should the measurement period not be configured to a factor of 1800 seconds. DNOs can resolve this issue by reconfiguring the measurement. As a result, it was deemed unnecessary to restrict the setting of the measurement period within SMETS or GBCS.

Who is impacted?

Electricity Network Parties
Meter Manufacturers

What SEC documents are affected?

SEC Schedule 9 'Smart Metering Equipment Technical Specifications'


12 Sep 2019
Draft Proposal raised
15 Nov 2019
Converted to Modification Proposal
04 Mar 2020
Working Group
10 Sep 2020
DCC Preliminary Assessment returned
07 Oct 2020
Working Group
01 Nov 2020
BEAMA request for information
22 Mar 2021
Modification split

Modification documents

MP085A Modification Report Consultation
MP085A Refinement Consultation responses
MP085A Refinement Consultation
MP085A July 2021 Working Group summary
MP085 February 2021 Working Group meeting summary
MP085 BEAMA consultation responses
MP085 October 2020 Working Group meeting summary
MP085 Business Requirements
MP085 DCC Preliminary Assessment
MP085A Legal Text v0.9
MP085A Modification Report v0.6
MP085 March 2020 Working Group meeting summary
DP085 Problem Statement
No files
No files
No files
No files
No files

If you believe there is a problem with this modification, please let us know HERE.

close slider