<div data-id="what-this-document-covers" style="text-align:left">What this document covers</div>

<div data-id="what-this-document-does-not-cover" style="text-align:left">What this document does not cover</div>

<div data-id="who-should-use-this-guidance-note" style="text-align:left">Who should use this Guidance Note?</div>

<div data-id="market-wide-half-hourly-settlement-mhhs" style="text-align:left">Market Wide Half Hourly <u class='defined-term'>Settlement</u> (MHHS)</div>

<div data-id="what-is-a-taa-inspection-visit" style="text-align:left">What is a TAA Inspection Visit?</div>

<div data-id="securing-site-access-for-a-taa-inspection-visit" style="text-align:left">Securing site access for a TAA Inspection Visit</div>

<div data-id="can-the-appointed-moa-work-on-the-metering-system-before-the-inspection-visit-takes-place" style="text-align:left">Can the Appointed MOA work on the metering system before the Inspection Visit takes Place?</div>

<div data-id="supplier-or-registrant-confirmation-of-a-taa-inspection-visit" style="text-align:left"><u class='defined-term'>Supplier</u> or <u class='defined-term'>Registrant</u> Confirmation of a TAA Inspection Visit</div>

<div data-id="information-required-from-audit-participants-before-a-taa-inspection-visit" style="text-align:left">Information required from audit participants before a TAA Inspection Visit</div>

<div data-id="moa-ldso-or-netso-attendance-at-a-taa-inspection-visit" style="text-align:left">MOA, <u class='defined-term'>LDSO</u> or NETSO attendance at a TAA Inspection Visit</div>

<div data-id="taa-working-instructions" style="text-align:left">TAA Working Instructions</div>

<div data-id="information-required-from-the-dc-or-cdca-following-a-taa-inspection-visit" style="text-align:left">Information required from the DC or <u class='defined-term'>CDCA</u> following a TAA Inspection Visit</div>

<div data-id="completing-a-taa-inspection-visit" style="text-align:left">Completing a TAA Inspection Visit</div>

<div data-id="what-must-i-do-once-the-taa-have-completed-an-inspection-visit" style="text-align:left">What must I do once the TAA have completed an Inspection Visit?</div>

<div data-id="do-you-need-more-information" style="text-align:left">Do you need more information?</div>

<div data-id="appendix-1" style="text-align:left">Appendix 1: Category 1 non-Compliances</div>

<div data-id="appendix-2" style="text-align:left">Appendix 2: Category 2 non-Compliances</div>

<div data-id="appendix-3" style="text-align:left">Appendix 3: Pro Forma <u class='defined-term'>Supplier</u> Letter Requesting Site Access for a TAA Inspection Visit</div>

<div data-id="appendix-4" style="text-align:left">Appendix 4: Using the National Measurement Transformer Error Statement (NMTES)</div>

<div data-id="reference-001--cop-determination" style="text-align:left">Reference 001 – CoP Determination</div>

<div data-id="reference-002--approved-protocols" style="text-align:left">Reference 002 – Approved Protocols</div>

<div data-id="reference-003--current-transformers-and-open-bars-appropriate-seals" style="text-align:left">Reference 003 – Current Transformers and Open Bars (Appropriate Seals)</div>

<div data-id="reference-004--metering-dispensations" style="text-align:left">Reference 004 – <u class='defined-term'>Metering Dispensation</u>s</div>

<div data-id="reference-005--complex-and-non-complex-sites" style="text-align:left">Reference 005 – Complex and Non-Complex Sites</div>

<div data-id="reference-006--measurement-uncertainty" style="text-align:left">Reference 006 – Measurement Uncertainty</div>

<div data-id="reference-007--onshore-and-offshore-cva-inspectionsaudits-including-aggregation-rules" style="text-align:left">Reference 007 – Onshore and <u class='defined-term'>Offshore</u> CVA Inspections/Audits (including <u class='defined-term'>Aggregation Rules</u>)</div>

<div data-id="reference-008--no-access-supplier-moa-and-ldso" style="text-align:left">Reference 008 – No Access, <u class='defined-term'>Supplier</u>, MOA and <u class='defined-term'>LDSO</u></div>

<div data-id="reference-009--passwords" style="text-align:left">Reference 009 – Passwords</div>

<div data-id="reference-010--phase-rotation" style="text-align:left">Reference 010 – Phase <span lang="en-GB"><b>Rotation</b></span></div>

<div data-id="reference-011--resolution-of-metering" style="text-align:left">Reference 011 – Resolution of <u class='defined-term'>Meter</u>ing</div>

<div data-id="reference-012--sealing" style="text-align:left">Reference 012 – Sealing</div>

<div data-id="reference-013--prevailing-load-test" style="text-align:left">Reference 013 – Prevailing Load Test</div>

<div data-id="appendix-5-0.0.1" style="margin-left: 3em">0.0.1 <span>In co-operation with the HHMOA the potential of the <u class='defined-term'>Meter</u> cabinet is checked with a reference earth ensuring the metering cabinet is not live. Any voltage detected is reported to the HHMOA. The visit is aborted where the fault cannot be immediately and safely rectified by the HHMOA. The TAAMT will be updated to record and report the condition, including what action the HHMOA has taken to ensure public safety from the equipment.</span></div>

<div data-id="appendix-5-0.0.2" style="margin-left: 3em">0.0.2 <span>The <u class='defined-term'>Meter</u> test facility is accessed (appropriate seals removed) and inspected for serviceability, (see figure 6). A visual inspection of the test facility and associated conductors is made to ensure measurement current transformers are not open circuited or short circuited. In accordance with TAA Working Instruction 010 – Phase Rotation the <u class='defined-term'>Metering System</u> phase rotation is checked.</span></div>

<div data-id="appendix-5-0.0.3" style="margin-left: 3em">0.0.3 <span>Using the handheld energy analyser the TAA measures and records the phase/line voltages. The voltage range will vary depending on the system arrangement – typically 110v line voltage for high voltage installations and 240V phase to neutral and 415v phase to phase for low voltage installations. (It should be noted that on the National Grid and some high voltage sites, it is possible that the voltage measurement could be 63.5v phase to neutral with metering arranged 3ph 4w).</span></div>

<div data-id="appendix-5-0.0.4" style="margin-left: 3em">0.0.4 <span>In conjunction with step 2 whilst the recording voltage measurements, following a risk assessment and determination of system arrangement, the TAA will apply the handheld energy analyser’s clip-on CT either on the primary or secondary conductor(s). The corresponding measurements are recorded including system power factor (multiple reads maybe necessary because of variations of load / generation in the primary circuit at the time the measurements are being taken.</span></div>

<div data-id="appendix-5-0.0.5" style="margin-left: 3em">0.0.5 <span>All measurement parameters are entered into the prevailing load database in the TAAMT.</span></div>

<div data-id="appendix-5-0.0.6" style="margin-left: 3em">0.0.6 <span>Over the measurement period a timed interval is monitored and <u class='defined-term'>Meter</u> readings taken depending on the <u class='defined-term'>Meter</u> display programming. Preferably the <u class='defined-term'>Meter</u> will have a demand register displaying either kW and/or kVA. Start and end readings are taken over a time period, typically ten minutes, however this can be adjusted in reflection of site load/generation. The TAA will ensure that the test period does not cross a half hour boundary, as the demand register resets. Alternatively, if no demand registers are available the cumulative reading can be used noting the value of the <u class='defined-term'>Meter</u> Register Multiplier.</span></div>

<div data-id="appendix-5-0.0.7" style="margin-left: 3em">0.0.7 <span>For those sites where the load is considered too low to obtain a valid test result (typically less than 5% of the circuit capacity)</span><span> </span><span>independent values can be referenced ensuring instant values at meter are matched.</span></div>

<div data-id="appendix-5-0.0.8" style="margin-left: 3em">0.0.8 <span>To complete end-to-end checks the cumulative kWh <u class='defined-term'>Meter</u> register is recorded at the start and end of a half hour demand period. The advance is compared to the results obtained by local interrogation of the <u class='defined-term'>Metering System</u>. Local interrogation results utilising propriety software are recorded and are used as evidence not only for checking the <u class='defined-term'>Meter</u> advance but also to perform a CDCC check upon receipt of data made available by the HHDC. Performing a local <u class='defined-term'>Meter</u> interrogation validates <u class='defined-term'>Meter</u> password security arrangements.</span></div>

<div data-id="appendix-5-0.0.9" style="margin-left: 3em">0.0.9 <span>Category 1 or 2 non-compliances will be raised where the test results indicate either that <u class='defined-term'>Settlement</u> Data Quality is, or there is a potential that <u class='defined-term'>Settlement</u> Data Quality is, affected.</span></div>

<div data-id="appendix-5-0.0.10" style="margin-left: 3em">0.0.10 <span>A “Note for Elexon” is recorded in TAAMT to confirm if Measurement Transformer Ratio was established</span></div>

<div data-id="reference-014--commissioning-for-metering-equipment-installed-before-6th-november-2018-or-where-the-metering-equipment-is-owned-by-the-customer" style="text-align:left">Reference 014 – Commissioning for <u class='defined-term'>Metering Equipment</u> installed before 6th November 2018 or where the <u class='defined-term'>Metering Equipment</u> is owned by the <u class='defined-term'>Customer</u></div>

<div data-id="reference-014a--commissioning-for-metering-equipment-installed-on-or-after-6th-november-2018-where-the-metering-equipment-is-owned-by-the-licenced-distribution-system-operator-ldso-or-transmission-company" style="text-align:left">Reference 014(A) – Commissioning for <u class='defined-term'>Metering Equipment</u> installed on or after 6<sup>th</sup> November 2018 where the <u class='defined-term'>Metering Equipment</u> is owned by the <u class='defined-term'>Licence</u>d <u class='defined-term'>Distribution System Operator</u> (<u class='defined-term'>LDSO</u>) or <u class='defined-term'>Transmission Company</u></div>

<div data-id="reference-014b--pre-june-1993-commissioning" style="text-align:left">Reference 014(B) – Pre-June 1993 Commissioning</div>

<div data-id="reference-015--cop4-records" style="text-align:left">Reference 015 – CoP4 Records</div>

<div data-id="reference-016--measurement-transformer-certificates" style="text-align:left">Reference 016 – Measurement Transformer Certificates</div>

<div data-id="reference-017--fusing-and-links" style="text-align:left">Reference 017 – Fusing and Links</div>

<div data-id="reference-018--outstation-time-keeping" style="text-align:left">Reference 018 – <u class='defined-term'>Outstation</u> Time Keeping</div>

<div data-id="reference-019--overall-accuracy" style="text-align:left">Reference 019 – Overall Accuracy</div>

<div data-id="reference-020--meter-compensation" style="text-align:left">Reference 020 – <u class='defined-term'>Meter</u> Compensation</div>

<div data-id="reference-021--duty-of-care" style="text-align:left">Reference 021 – Duty of Care</div>

<div data-id="reference-022--checking-that-main-and-check-meters-are-correctly-identified" style="text-align:left">Reference 022 – Checking that Main and Check <u class='defined-term'>Meter</u>s are correctly identified</div>

<div data-id="reference-023-defined-metering-point" style="text-align:left">Reference 023– Defined <u class='defined-term'>Metering Point</u></div>

<div data-id="appendix-5" style="text-align:left">Appendix 5: TAA Working Instructions</div>

CONTENTS

Performance Assurance: TAA Inspection Visit Local Working Instruction V7.0