MP085A Synchronisation of smart meter voltage measurement periods

Proposer Alan Creighton
Lead Analyst Bradley Baker
Date raised 12/09/2019
StageRefinement Process
Implementation date Unknown
Latest update MP085 was split into two separate modifications on 22 March 2021. Following discussion at TABASC and the July Working Group SECAS is working with the Proposer and TABASC Chair to further refine the legal text ahead of the Refinement Consultation.

What is the issue?

The expectation of Electricity Network Parties during the development of the smart meter technical specification was that the average 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 amend SMETS to state that any changes to the Average RMS Voltage Measurement Period are applied from the start of the next hour according to the Device’s clock. Users will be able to choose a measurement period from 11 pre-determined values. The maximum length will be 1,800 seconds (30 minutes), and all other values will be factors of 1,800.

If a DNO attempts to set the measurement period to a length outside of the above 11 values, a new DSP validation check will be failed, resulting in the Service Request (SR) being rejected along with producing a new error code, notifying the DNO that their request has been unsuccessful.

Who is impacted?

Electricity Network Parties
Meter Manufacturers

What SEC documents are affected?

SEC Schedule 9 'Smart Metering Equipment Technical Specifications'
SEC Appendix AD 'DCC User Interface Specification'


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 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
MP085 Legal Text
MP085A Modification Report
MP085 March 2020 Working Group meeting summary
DP085 Problem Statement
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