HomeRulebook HomeBalancing and Settlement CodeGuidance NotesLine Loss Factor Submission Audit and Approval
Previous version
Next version

CONTENTS

  • Line Loss Factor Submission, Audit and Approval
    • BSCP128 Methodology and LLF Submission
    • High level timeline for Line Loss Factor Submission, Audit and Approval
    • What does it all mean?
    • BSCP128 Principles
      • 1. LLFs shall be calculated using a generic (non Site Specific) method except for:
      • 2. All LLFs shall be calculated to at least three decimal places and submitted to three decimal places.
      • 3. All Site Specific LLFs shall account for Technical Losses only.
      • 4. All Generic LLFs shall account for all losses (Technical and Non Technical).
      • 5. Site-Specific losses and the total Grid Supply Point Group (GSPG) losses shall be considered in the calculation of Generic LLFs.
      • 6. Non-EHV Generic LLFs for Import and Export at the same site where the voltage level is the same shall have the same values.
      • 7. There shall be no more than two Low Voltage (LV) and two High Voltage (HV) Generic LLFC/DUoS Tariff ID Groups, in each GSPG, and at least one Generic EHV LLFC/DUoS Tariff ID Group. All DUoS Tariff IDs to be mapped to an appropriate LLFid
      • 8. As a minimum, generic LLFs shall be calculated separately for Day and Night.
      • 9. LDSOs shall use Settlement data from a Settlement Run at R3 or greater and from a complete 12-month period, for calculating Generic LLFs. The 12-month period to be used shall be the BSC Year three years prior to the BSC Year for which the LLFs are being calculated.
      • 10. Adjustments to calculation or application of LLFs, to take into account historic market wide issues noted in the BSC Auditor’s latest Report, can only be made if agreed to be appropriate by the Panel.
      • 11. Robust error detection and correction processes shall be in place throughout the calculation and submission of LLFs.
      • 12. All Generic LLFs shall be re-calculated at least every two years.
      • 13. All Site-Specific LLFs shall be re-calculated when there has been a relevant change to the site or network, and at least every 5 years.
      • 14. No changes shall be made to approved Generic LLFs mid year. Annual updates will have an effective from date of 1 April. Where default LLFs have been applied due to an audit failure, these may be replaced with approved LLFs on a prospective basis as determined when the LLFs resubmitted by the LDSO have been approved by the Panel.
      • 15. No retrospective changes shall be made to approved Site-Specific or Generic LLFs other than to correct material manifest errors.
      • 16. Changes shall only be made to approved Site Specific LLFs mid-year if there has been a material change affecting the site; and the revised LLFs have been approved by the Panel. Annual updates will have an effective from date of 1 April. Where default LLFs have been applied due to an audit failure, these may be updated to the approved LLFs on a prospective basis as determined from time to time by the Panel.
      • 17. Where the usage profile for a given site contains insufficiently large consumption or generation volumes to enable calculation of realistic Site Specific LLFs then a default calculation, or default replacement process shall be undertaken.
    • Methodology Review
    • When do I submit my methodology and MSAD?
    • What information do I include in the MSAD for Host LDSOs?
    • What information do I include in the MSAD for Embedded LDSOs that Mirror?
    • What information do I include in the methodology to conform to Principle 17?
    • How will my methodology be reviewed?
    • What happens if my methodology is non-compliant?
    • When will I know if my methodology has been approved?
  • LLF Audit for Host LDSOs and Embedded LDSOs that do not Mirror
    • Submitting LLFs and CSADs during the Market-wide Half-Hourly Settlement (MHHS) transition period
    • When do I submit my Line Loss Factors and CSAD?
    • In what format do I submit the LLFs?
    • How do I submit the SToD period file?
    • What information do I include in the CSAD (Appendix 3 of BSCP128)?
    • What do the terms in the CSAD Appendices (Section 2) tables mean?
    • How to indicate application of Principle 17 in CSAD (BSCP128 Appendix 5)?
    • The Notes tab
    • The SVA Data tab
    • The Notes tab
    • The SVA Data tab
    • Submitting Additional Information with your CSAD
    • What happens to your LLF submission?
    • What happens if validation fails?
    • How will you check Metering Systems have the correct LLFC?
    • When will the site visit happen?
    • What happens on the site visit?
    • Opening meeting
    • Audit interview
    • LLF calculation demonstration
    • MPAN Sampling (also for Embedded LDSOs that Mirror)
    • Closing meeting
    • What happens if the audit identifies non-compliance?
    • When will I know if my LLFs are approved?
    • How will the LLFs reach the BSC Central Systems?
  • LLF Audit for Embedded LDSOs that mirror
    • How does the audit differ from the Host LDSO audit?
    • Submitting your SVA short format file (Request Template) and supporting documents during the MHHS transition period
    • When do I submit my Line Loss Factors and CSAD?
    • What information do I include in the CSAD (Appendix 4 of BSCP128)?
    • What information do I include in the CSAD (Appendix 5 of the BSCP128)?
    • How do I populate SVA short file (i.e. Request Template)?
    • What happens if the audit identifies a non-compliance?
  • Mid-Year LLF Submissions
    • When can I submit mid-year generic LLF changes?
    • Are mid-year submissions applied retrospectively?
    • Can I change the approved Site-Specific LLFs mid-year?
    • Do I need to submit a Mid-Year CSAD or Request Template for a new DUoS Tariff ID or LLF ID?
    • Can I use the same DUoS Tariff ID in different GSP Groups?
  • Other Frequently Asked Questions
    • What if there is a new site built mid-year? Does Principle 16 allow for new Site-Specific values to be applied mid-year?
    • Do the Principles exclude sites changing from one LLFC/DUoS Tariff ID to the other?
    • Will we audit external consultants who calculate LLFs on my behalf?
    • Does the LLF calculations audit take place every year?
    • What are the Standardised Generic LLF IDs?
    • If there are errors or warnings from the CSAD or Request Template submission, please see the tables below
  • Need more information?

Line Loss Factor Submission, Audit and Approval V10.0

Effective From Date:22/08/2025
Status:LIVE
Other versions
Download