This is the Service Description for the Transmission Loss Factor Agent (TLFA) appointed by ELEXON to derive Transmission Loss Factors under the BSC.

<div data-id="1" style="margin-left:0.59in;text-align:left;text-indent:-0.59in">1. Introduction</div>

<div data-id="3" style="margin-left:0.59in;text-align:left;text-indent:-0.59in">3. Input Data Requirements</div>

<div data-id="4" style="margin-left:0.59in;text-align:left;text-indent:-0.59in">4. <u class='defined-term'>Load Flow Model Specification</u> and <u class='defined-term'>Load Flow Model</u></div>

<div data-id="5" style="margin-left:0.59in;text-align:left;text-indent:-0.59in">5. Determination of <u class='defined-term'>Transmission Loss Factor</u>s</div>

<div data-id="6" style="margin-left:0.59in;text-align:left;text-indent:-0.59in">6. Data Outputs</div>

<div data-id="7" style="margin-left:0.59in;text-align:left;text-indent:-0.59in">7. Non-Functional Requirements</div>

<div data-id="8" style="margin-left:0.59in;text-align:left;text-indent:-0.59in">8. Appendix A – Terms, Acronyms and Definitions</div>

<div data-id="9" style="margin-left:0.59in;text-align:left;text-indent:-0.59in">9. Appendix B – Interface Details</div>

<div data-id="9" style="margin-left:0.59in;text-indent:-0.59in;text-align: justify">9.1 Interface Details</div>

<div data-id="9" style="margin-left:0.59in;text-indent:-0.59in;text-align: justify">9.2 Network Mapping Statement (Input): <u class='defined-term'>TLFA</u>-I001</div>

<div data-id="9" style="margin-left:0.59in;text-indent:-0.59in;text-align: justify">9.3 <u class='defined-term'>Load Period</u>s and <u class='defined-term'>Sample Settlement Period</u>s (Input): <u class='defined-term'>TLFA</u>-I002</div>

<div data-id="9" style="margin-left:0.59in;text-indent:-0.59in;text-align: justify">9.4 <u class='defined-term'>Transmission Network Data</u> (Input): <u class='defined-term'>TLFA</u>-I004</div>

<div data-id="9" style="margin-left:0.59in;text-indent:-0.59in;text-align: justify">9.5 HVDC <u class='defined-term'>Metered Data</u> for <u class='defined-term'>Sample Settlement Period</u>s (Input): <u class='defined-term'>TLFA</u>-I005</div>

<div data-id="9" style="margin-left:0.59in;text-indent:-0.59in;text-align: justify">9.6 <u class='defined-term'>Distribution Network Data</u> (Input): <u class='defined-term'>TLFA</u>-I006</div>

<div data-id="9" style="margin-left:0.59in;text-indent:-0.59in;text-align: justify">9.7 Total Delivering and Offtaking <u class='defined-term'>Metered Volume</u> Data (Input): <u class='defined-term'>TLFA</u>-I007</div>

<div data-id="9" style="margin-left:0.59in;text-indent:-0.59in;text-align: justify">9.8 Nodal <u class='defined-term'>Transmission Loss Factor</u>s (Output): <u class='defined-term'>TLFA</u>-I008</div>

<div data-id="9" style="margin-left:0.59in;text-indent:-0.59in;text-align: justify">9.9 Adjusted Seasonal Zonal <u class='defined-term'>Transmission Loss Factor</u>s (Output): <u class='defined-term'>TLFA</u>-I009</div>

<div data-id="9" style="margin-left:0.59in;text-indent:-0.59in;text-align: justify">9.10 <u class='defined-term'>BM Unit</u> Specific <u class='defined-term'>Transmission Loss Factor</u>s (Output): <u class='defined-term'>TLFA</u>-I010</div>

<div data-id="9" style="margin-left:0.59in;text-indent:-0.59in;text-align: justify">9.11 Seasonal Zonal TLFs (Output): <u class='defined-term'>TLFA</u>-I011</div>

<div data-id="9" style="margin-left:0.59in;text-indent:-0.59in;text-align: justify">9.12 <u class='defined-term'>Metered Volume</u> Data for <u class='defined-term'>Sample Settlement Period</u>s (Input): <u class='defined-term'>TLFA</u>-I003</div>

<div data-id="9" style="margin-left:0.59in;text-indent:-0.59in;text-align: justify">9.13 TLF Adjustment (Output): <u class='defined-term'>TLFA</u>-I012</div>

<div data-id="9" style="margin-left:0.59in;text-indent:-0.59in;text-align: justify">9.14 Indicative TLM &amp; TLMO Values - Part 1 (Output): <u class='defined-term'>TLFA</u>-I013</div>

<div data-id="9" style="margin-left:0.59in;text-indent:-0.59in;text-align: justify">9.15 Indicative TLM &amp; TLMO Values - Part 2 (Output): <u class='defined-term'>TLFA</u>-I014</div>

<div data-id="9" style="margin-left:0.59in;text-indent:-0.59in;text-align: justify">9.16 Adjusted Nodal Power Flows (Output): <u class='defined-term'>TLFA</u>-I015</div>

<div data-id="9" style="margin-left:0.59in;text-indent:-0.59in;text-align: justify">9.17 Branch Power Flows<sup>1</sup> (Output): <u class='defined-term'>TLFA</u>-I016</div>

<div data-id="9" style="margin-left:0.59in;text-indent:-0.59in;text-align: justify">9.18 Absolute Nodal Power Flows (Output): <u class='defined-term'>TLFA</u>-I017</div>

CONTENTS

Service Description for Transmission Loss Factor Agent Determination V4.0