CONTENTS
Technical Assurance of Metering How to rectify common non-compliances
Technical Assurance of Metering How to Rectify Common Non-Compliances |
Guidance Note |
Summary
A Registrant,
A Supplier
A Party Agent, or
A Licensed Distribution System Operator
What is the Technical Assurance of Metering?
1% of the HH Supplier Volume Allocation (SVA) Metering System population,
5% of the HH Central Volume Allocation (CVA) Metering System population,
A ‘specific sample’ designed to look at particular areas of risk to the HH Metering System population, and is directed by the Performance Assurance Board (PAB). This can be up to 20% of the HH SVA sample.
NC (or NP): A Consumption Data Comparison Check (CDCC) is performed. The TAA takes data directly from the Metering System, and directly compares this data with that taken by the DC. A non-compliance is applied where the two sets of data do not match.
Where it can’t be performed NP is recorded, this does not need to be rectified.
Category 1: affects the quality of data for Settlement purposes.
Category 2: potentially affects the quality of data for Settlement purposes (but doesn’t currently affect it).
Observation: inconsistencies with Code of Practice (CoP) requirements, but doesn’t affect, or potentially affect the quality of data for Settlement purposes.
What else do I need to know?
With multi-ratio CTs and VTs you need to make sure the ratio selected on site matches the ratio underlined in the NMTES Ratio column. This is because the underlined number indicates the primary to secondary ratio for which the generic Error listed relates (e.g. 100/50/5 means that the generic Error quoted relates to a 100/5 setting on the CT and not the 50/5 setting).
After the TAA Inspection Visit
Where this is the case you can use the Error figure associated with it to help clear the ‘overall accuracy not maintained’ non-compliance.
Where a CT / VT needs replacing, the MOA is assigned responsibility in the TAAMT. However, to replace the CT / VT the MOA and LDSO need to work closely to complete the actions.
Where certificates for Metering Equipment are required, the MOA and LDSO need to work collaboratively to provide to the TAA.
BSCP27: Technical Assurance of Metering and appropriate Metering Codes of Practice
TAA Working Instruction Documents - These are documents that detail the process for the TAA Inspector to refer to when assessing a Metering System for compliance to the BSC and its Code Subsidiary Documents. They also provide assurance that the Inspectors follow a consistent approach. These documents are published on the Technical Assurance of Metering page of the BSC Website.
The Technical Assurance Agent Management Tool - www.elexon-assurance.co.uk
Appendix A
The common non compliances raised by the TAA
Who is responsible for fixing them
Which standard rectification plan should be used in the TAAMT
What actions we recommend to rectify these non-compliances
NC | NC Category Description – What the problem is | Who is assigned as the responsible party to the NC? | Which Standard Rectification Plan could I use in the TAAMT? | What else do I need to know to help me rectify this NC? | ||||||
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| Registrant | MOA | DC |
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NC | Comparison Identified inconsistent data. Consumption data held by Data Collector outside tolerance when compared with metered energy data. | |
| | Other | This will affect the quality of data entering into the Settlement process. To rectify this NC the DC will need to work with the MOA to confirm / resolve site arrangements. The MTDs must be updated as necessary and be re-issued to the required participants as set out in the relevant BSC documentation. The relevant fault investigation process is adequate for supporting this process. Re-commissioning must occur and updated MTDs and applicable evidence should be provided to the TAA. | ||||
Inaccuracy of Standing Data (Key MTD fields) held by Data Collector | ||||||||||
1.01 | Meter Id (Serial Number) | |
| | Provide correct D0268 Data (SVA) Other (CVA – provide corrected MTDs as per BSCP20) | If these data items are incorrect in the DC system, it will affect the way the data is translated from the Metering System and entered into the Settlement process. To rectify this, NC the DC will need to work with the MOA to confirm site arrangements and ensure that they are adequately reflected in the MTDs before being loaded into the DC system. The MTDs must be updated as necessary and be re-issued to the required participants as set out in the relevant BSC documentation, as necessary. The relevant fault investigation process is adequate for supporting this process. Re-commissioning must occur, as necessary, and any updated MTDs and applicable evidence should be provided to the TAA. | ||||
Outstation number of channels | ||||||||||
Measurement Quantity Id | ||||||||||
Pulse Multiplier | ||||||||||
Channel configuration | ||||||||||
Outstation multiplier / Outstation channel multiplier | ||||||||||
Complex Site Supplementary Information Form (SVA only) | ||||||||||
Metering Equipment Incorrect or Unsatisfactory | ||||||||||
1.02 | Metering Equipment not functioning correctly | | |
| Change / Replace the metering System Equipment | Errors of this nature affect the quality of data that enters Settlement and as such must be rectified. Rectification of this NC requires a change/exchange to the Metering Equipment. Attendance and rectification by the relevant SO may be required. The MTDs must be updated, as necessary, and be re-issued to all parties in line with the BSC. Re-commissioning must occur, as necessary, and evidence should be provided to the TAA. Alternative actions may be to seek Metering System Dispensation approval through the relevant process. | ||||
Metering Equipment not programmed correctly | ||||||||||
Overall accuracy of Metering System not maintained | ||||||||||
Summation CTs used | ||||||||||
Correct Energy Measurement Check (Primary/Secondary conductor prevailing load test) indicates an error in the metered volume | ||||||||||
Timing Error (Major) | ||||||||||
1.03 | Outstation clock outside of agreed tolerance | | | | Correct the Metering System Clock | MOA must work with the DC to investigate and correct any clock drift exceeding the parameters set out: CoP 1 >± 30 seconds, CoP 2 >± 30 seconds, CoP 3 >± 1 minute, Cop 5 >± 2 minutes. If the Meter or Outstation clock is continually falling outside these tolerances, then it may be appropriate to replace the equipment entirely. Re-commissioning must occur, as necessary, and evidence should be provided to the TAA. | ||||
Measurement transformer Ratios Physically Incorrect | ||||||||||
1.04 | Measurement transformer ratios different from those set up in Meter (save for any difference being consistent with a measurement error compensation applied within the metering Equipment) | | |
| Change / replace Metering System Equipment Provide correct D0268 Data (SVA) Other (CVA – provide corrected MTDs as per BSCP20) | To rectify this NC the MOA is required to re-programme the Meter and update MTDs as necessary, reissuing to required participants as set out in the relevant BSC documentation. Re-commissioning must occur, as necessary, and evidence should be provided to the TAA. | ||||
Compensation Calculations Incorrect | ||||||||||
1.05 | Meter compensation for Measurement Transformers incorrectly applied or not applied | | |
| Change / replace Metering System Equipment Provide correct D0268 Data (SVA) Other (CVA – provide corrected MTDs as per BSCP20) | The MOA must apply the Meter compensations correctly. This NC indicates that no commissioning had taken place (if it had, it would have shown the error). The MTDs must be updated as necessary and be re-issued to the required participants as set out in the relevant BSC documentation. Re-commissioning must occur, as necessary, and evidence should be provided to the TAA. The MTDs must be updated as necessary and be re-issued to all parties in line with the BSC. | ||||
| Meter compensation for Power Transformers incorrectly applied or not applied | |||||||||
Inaccuracy of Standing Data held by Meter Operator Agent | ||||||||||
2.01 | Outstation serial number | | |
| Provide correct D0268 Data (SVA) Other (CVA – provide corrected MTDs as per BSCP20) | It is the MOAs obligation to ensure the MTDs are accurate and correct. Where the MOA MTDs do not match the equipment on site the MOA must update the MTDs, as necessary, and re-issue to the required parties in line with the BSC. Evidence of rectification should be provided to the TAA. | ||||
Meter Id (serial number) | ||||||||||
Outstation number of channels | ||||||||||
Measurement Quantity Id | ||||||||||
Meter Register Multiplier | ||||||||||
Pulse multiplier | ||||||||||
Channel configuration | ||||||||||
Outstation multiplier / Outstation channel multiplier | ||||||||||
Measurement Transformer Ratios | ||||||||||
Complex Site Supplementary Information Form (SVA only) | ||||||||||
Inaccuracy of Standing Data (non-Key MTD fields) held by Data Collector | ||||||||||
2.02 | Data Collector’s Meter Technical Details do not match on site equipment due to recent Meter Exchange |
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| Provide correct D0268 Data (SVA) Other (CVA – provide corrected MTDs as per BSCP20) | Ensure the Meter exchange is genuine, as a result of the fault investigation or tamper investigate process. The MTDs must be updated as necessary and be re-issued to the required participants as set out in the relevant BSC documentation. Re-commissioning must occur, as necessary, and evidence should be provided to the TAA. | ||||
Other non-Key fields (e.g. Measurement Transformer Ratios & Meter Register Multiplier) | MOA may need to work with the LDSO to ensure that this NC is rectified. The MTDs must be updated as necessary and be re-issued to the required participants as set out in the relevant BSC documentation. Re-commissioning must occur, as necessary, and evidence should be provided to the TAA. | |||||||||
Non-provision of Standing Data | ||||||||||
2.03 | Meter Technical Details not provided – Meter Operator Agent and Data Collector | | | | Provide correct D0268 Data (SVA) Other (CVA – provide corrected MTDs as per BSCP20) | The MTDs must be provided to the TAA for inspection. BSCP27 states that all MTDs must be provided prior to the inspection visit, except for the MOA who may take these details to the inspection visit. | ||||
2.06 | Incorrect CoP applied |
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| Change / replace Metering System Equipment Provide Correct D0268 Data (SVA) Other (CVA – provide corrected MTDs as per BSCP20) | MOA must apply the correct CoP. Re-commissioning must occur where changes to the physical set up of the Metering Equipment have taken place and evidence should be provided to the TAA. Any updated MTDs must be provided to all parties in line with the BSC. | ||||
Check Meter missing | MOA must ensure that where the CoP requires, a check meter is both fitted and detailed in the MTDs. Any updated MTDs must be provided to all parties in line with the BSC. After all necessary work re-commissioning must occur and evidence should be provided to the TAA. | |||||||||
Main Meter missing. Check Meter present and accurate | This may be an administrative or a physical NC or both. Where it is administrative, rectification requires the MTDs to be updated and these must be provided to all parties in line with the BSC. If the NC is physical, the MOA must ensure that the Metering System complies with the appropriate CoP and update the MTDs. Any updated MTDs must be provided to all parties in line with the BSC. Re-commissioning must occur, as necessary, and evidence must be provided to the TAA. | |||||||||
Meter accuracy class incorrect | MOA must apply the correct meter accuracy class to the Meter. Any updated MTDs must be provided to all parties in line with the BSC. Re-commissioning must occur, as necessary, and evidence should be provided to the TAA. | |||||||||
2.06 Cont’d | CT accuracy class incorrect |
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| Change / replace Metering System Equipment Provide Correct D0268 Data (SVA) Other (CVA – provide corrected MTDs as per BSCP20) | MOA must apply the correct CT accuracy class to the Meter. Any updated MTDs must be provided to all parties in line with the BSC. Re-commissioning must occur, as necessary, and evidence should be provided to the TAA. | ||||
VT accuracy class incorrect | MOA must apply the correct VT accuracy class to the Meter. Any updated MTDs must be provided to all parties in line with the BSC. Re-commissioning must occur, as necessary, and evidence should be provided to the TAA. | |||||||||
Voltage selection relay not installed/working when summation CT’s used | MOA must repair or replace the voltage selection relay or install one if necessary. Any updated MTDs must be provided to all parties in line with the BSC. Re-commissioning must occur, as necessary, and evidence should be provided to the TAA. | |||||||||
Possibility that overall accuracy of Metering System not maintained | Supplier and MOA (with assistant of the relevant SO) must provide all documentation to enable Overall Accuracy to be calculated. Failing that the NMTES should be used where applicable in the SVA Market. If the NC is the result of a physical metering problem, the MOA and the relevant SO will need to replace the Metering Equipment or adjust the Meter to compensate if possible. The MTDs must be updated as necessary and be re-issued to the required participants as set out in the relevant BSC documentation. Re-commissioning must occur and evidence should be provided to the TAA. | |||||||||
2.06 Cont’d | Unapproved data format and protocol in use |
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| Change / replace Metering System Equipment Provide Correct D0268 Data (SVA) Other (CVA – provide corrected MTDs as per BSCP20) | This NC requires that the Meter or Outstation is replaced. The MTDs must be updated and re-issued to the required participants as set out in the relevant BSC documentation. Re-commissioning must occur and evidence should be provided to the TAA. | ||||
Unsuitable Environment | ||||||||||
2.08 | Environmental conditions likely to cause Metering Equipment failure |
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| Other (Please provide a description when submitting your rectification plan) | MOA and Supplier must arrange to either move or protect the Metering Equipment. Re-commissioning must occur, as necessary, and evidence should be provided to the TAA. | ||||
Inadequate Over-current Protection |
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2.09 | Insufficient discrimination between source and local fusing |
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| Change / replace Metering System Equipment Provide corrected D0268 data (SVA) Other (CVA – provide corrected MTDs as per BSCP20) | MOA must ensure that the fusing set up is correct. Any updated MTDs must be provided to all parties in line with the BSC. Re-commissioning must occur, as necessary, and evidence should be provided to the TAA. |
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No local isolation | MOA must ensure that isolation is provided at the Meter in line with CoP requirements. Any updated MTDs must be provided to all parties in line with the BSC. Re-commissioning must occur, as necessary, and evidence should be provided to the TAA. |
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Main and check Meters not separately fused | MOA must ensure that main and check meters are separately fused. Any updated MTDs must be provided to all parties in line with the BSC. Re-commissioning must occur, as necessary, and evidence should be provided to the TAA. |
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Other Metering Equipment not separately fused | MOA must ensure that all aspects of the Metering Equipment are separately fused. Any updated MTDs must be provided to all parties in line with the BSC. Re-commissioning must occur, as necessary, and evidence should be provided to the TAA. |
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Non-Settlement Meters not separately fused | MOA must ensure that all aspects of the Metering Equipment are separately fused. Any updated MTDs must be provided to all parties in line with the BSC. Re-commissioning must occur, as necessary, and evidence should be provided to the TAA. |
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Separate Phase Failure Alarms Not Installed or Inadequate / Failed – Local and Remote |
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2.10 | Alarm not fitted where required | | |
| Change / replace Metering System Equipment Provide corrected D0268 data (SVA) Other (CVA – provide corrected MTDs as per BSCP20) | MOA must exchange the Meter for one that has a phase alarm fitted. Any updated MTDs must be provided to all parties in line with the BSC. Re-commissioning must occur and evidence should be provided to the TAA. |
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Alarm not functioning |
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Inadequate Metering Equipment Integrity |
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2.11 | Settlement Metering Equipment not sealed | | |
| Change / replace Metering System Equipment Provide corrected D0268 data (SVA) Other (CVA – provide corrected MTDs as per BSCP20) | MOA must ensure that Metering Equipment is sealed in line with the CoP and MOCOPA (SVA) / BSC (CVA) provisions. Re-commissioning must occur, as necessary, and evidence should be provided to the TAA. |
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| Password functionality not included in Outstation |
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| MOA must ensure that the outstation has password capability if required. Any updated MTDs must be provided to all parties in line with the BSC. Re-commissioning must occur, as necessary, and evidence should be provided to the TAA. |
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Timing Error (Minor) |
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2.14 | Outstation clock outside agreed tolerance | | | | Correct the Metering System Clock Provide Corrected D0268 data (SVA) Other (CVA – provide corrected MTDs as per BSCP20) | The DC must trim the clock to correct. Where meters do not allow this to be done in one instance, then it must be done progressively. CoP 1 ± 20 seconds to 30 seconds CoP 2 ± 20 seconds to 30 seconds CoP 3 ± 20 seconds to 1 minute CoP 5 ± 20 seconds to 2 minutes If the Meter or Outstation clock is continually falling outside these tolerances, then it may be appropriate to investigate further following the relevant fault investigation process set out in the BSC and may lead to a replacement of Metering Equipment. If replacement is required the MTDs must be updated and provided to all parties in line with the BSC. Re-commissioning must occur and evidence should be provided to the TAA. |
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Commissioning Records |
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2.15 | Commissioning records not provided | | |
| Provide Certificates | Records must be provided or re-commissioning must take place and evidence provided to the TAA. |
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Commissioning records incorrect |
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Commissioning records incomplete |
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Measurement Transformer Certificates not provided or incorrect |
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2.16 | Measurement Transformer Certificates not provided | | |
| Provide Certificates | Records must be provided or MOA can use the NMTES, if the Measurement Transformers are on it. |
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Measurement Transformer Certificates do not match site equipment |
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Meter Certificates not provided or incorrect |
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2.17 | Meter Certificates not provided | | |
| Provide Certificates | Records must be provided and evidence provided to the TAA. |
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Meter Certificates do not match site equipment |
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Labelling Inconsistency |
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0.16 | Main/Check/Import/Export | | |
| n/a | Metering Equipment must be labelled correctly and if necessary changes to the physical set up. |
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Circuits (feeders) |
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Measurement Transformer ratios and / or polarity |
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Test Terminal Block connections |
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Test Terminal Block |
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0.19 | Test Terminal Block not fitted / inappropriate | | |
| n/a | The MOA must ensure that the Metering System has a test terminal Block fitted and working effectively. |
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Unauthorised Access |
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0.20 | Possible unauthorised access to Meter location which could lead to interference with Metering Equipment | | |
| n/a | Access to the Meter location must be secured by the MOA or SO as applicable. Access must only be provided to the Meter location by the required parties in line with the BSC. |
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