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Market Domain Data Frequently Asked Questions (FAQs)

v 6.0

Market Domain Data Frequently Asked Questions (FAQs)

Guidance Note

The questions below are those commonly asked by market participants about the Market Domain Data (MDD) process.

Where can I obtain MDD data from?

The most recent version of MDD is published on the Elexon Portal, or in data flows format. If you need a copy of the dataflow, please contact the BSC Service Desk or call 0370 010 6950.

What is the MDD Load Utility and how do I obtain it?

The MDD Load Utility Tool is a Microsoft Access database that converts the D0269 flows in to a readable format. It replicates the MDD system maintained by the Supplier Volume Allocation Agent (SVAA). The MDD Load Utility and the User Guide are published on the MDD webpage.

What are the differences between the D0269 and D0270 flows?

The D0269 flow is the MDD complete set, and the D0270 flow is the MDD incremental set. Both flows have two versions and variants of each version:

    • D0269002 and D0270002 (each with or without regression data)

    • D0269004 and D0270004 (each with or without regression data).

The version 004 flows include the additional import/export flag on the Standard Settlement Configuration (SSC) record and the new Entity 63 Valid MTC SSC LLFC PC Combinations.

Regression data is used in conjunction with daily variables (i.e. temperatures, Teleswitch, sunset data) to calculate sets of Profile Coefficients to estimate half hourly demand for non-half hourly customers.

I am a new market participant. How do I create a new market participant identifier (MPID) for my organisation?

You need to complete the relevant Market Entry and Qualification steps before obtaining a Market Participant Identifier (MPID). Once completed, you can choose a unique four alpha character ID, as long as this ID does not exist for another participant. You must also liaise with Electralink to set up your Data Transfer Network (DTN) configuration. For more details please see BSCP509 Appendix 2.

How do I set up a new Tariff?

Setting up a new tariff requires a new SSC, Meter Timeswitch Class (MTC), Time Pattern Regime (TPR), Clock Interval/Teleswitch details, Measurement Requirement information and Line Loss Factor Classes (LLFC). Depending on what area the tariff is being set up in, you must liaise with the Licensed Distribution System Operator (LDSO) to ensure the tariff is compatible in their area. More information on setting up new combinations is available in BSCP509 Appendix 2.

How do I end date a combination?

To end-date any data item in MDD you need to raise a change request. The ‘Effective To Date’ on your chosen form needs to be on or after the MDD Go-Live Date for the MDD version the change request will be implemented in. Where a parent combination is end-dated, you may also need to end-date any child combinations attached.

How can I tell whether an SSC and Profile Class are valid for a particular GSP Group?

When a new tariff is set up, the Supplier includes an ‘Average Fraction of Yearly Consumption Set’ (AFYC). This tells you which SSCs and Profile Classes are set up in a particular GSP group with the AFYC values against the respective TPRs.

I can’t view the Teleswitch Switching Times in the MDD Database, where can I get this data from?

We don’t hold Teleswitch switching times in the MDD database as the switching times are, to some extent, dynamic. The Teleswitch Agent provides the SVAA with a file daily. This file allows the SVAA to derive the actual switching times. The SVAA rounds the Teleswitch switching times to start and end on half hour Settlement Periods. Retrospective data on switching times are available in the D0018 ‘Daily Profile Data Report’ flow.

When can I obtain the SVAA Settlement Calendar?

The SVAA Settlement Calendar is usually entered into MDD every February, and is triggered by the completion of the Funds Allocation Agent (FAA) payment calendar.

How do I calculate an AFYC Value for a new tariff item?

Initial values can be agreed with the LDSO. Each year the SVAA calculates the actual energy Settled on each meter register or TPR, and the values are updated in MDD as more customers are put on to the tariff. All AFYC values must sum up to one across the relevant meter registers.

How do I create a Half Hourly combination in MDD?

Half Hourly combinations are created by completing an Entity 55 (Valid MTC LLFC combination) form, as long as the MTC and LLFC already exist. Where a new MTC and LLFC have to be created, you will need to complete a BSCP509 Entity 17 form (Line Loss Factor Class) and a BSCP509 Entity 52 form (Meter Timeswitch Class).

    • BSCP509 Entity 17 form (Line Loss Factor Class)

    • BSCP509 Entity 52 form (Meter Timeswitch Class) form

    • BSCP509 Entity 55 form (Valid MTC LLFC combination) form.

How do I create a Non Half Hourly combination in MDD?

When creating a Non Half Hourly combination, the first check ensures that the Meter Timeswitch Class is available within that distribution area by filling out an Entity 53 (Meter Timeswitch Class for Distributor) form. The combination is then built up from an Entity 54 (Valid MTC SSC Combination) by adding an SSC to the MTC combination, Entity 56 (Valid MTC LLFC SSC Combination) which adds the Line Loss Factor to the combination, and an Entity 63 (valid MTC LLFC SSC PC Combination) which replicates the Distribution Use of System (DUOS) charging statements.

    • BSCP509 Entity 53 form (Meter Timeswitch Class for Distributor)

    • BSCP509 Entity 54 form (Valid MTC SSC Combination)

    • BSCP509 Entity 56 form (Valid MTC LLFC SSC Combination)

    • BSCP509 Entity 63 form (valid MTC LLFC SSC PC Combination)

The BSCP509 Appendix 1 MDD Entity Change Request Forms are available on the BSC Website in Word format; click the Forms button to download them.

What is the MTC numbering convention?

Meter Timeswitch Classes (MTCs) were designed to allow Suppliers to identify the metering installed in Customers’ premises. Amongst other things, they indicate whether the meter is single or multi-rate, prepayment or credit, or whether it is ‘related’ to another meter (that is, where there are two meters in a property; one for general load, and one for heating and where a Supplier must register both meters).

MTC ID Range



Specific to Distribution Network


Currently not in use


Codes for related Metering Systems and common across Britain.


Codes for related Metering Systems and Distribution Network specific.


Codes common across Britain.

Need more information?

If you have any further questions, or there is any area of MDD that is not covered above, please email

For more information please contact the BSC Service Desk or call 0370 010 6950.

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