Three weeks ago, MET Labs joined other C12 Accredited Standards Committee members in St. Louis, MO at the EEI Transmission, Distribution & Metering Conference to discuss revisions to ANSI C12.1, which provides the basic requirements for all kilowatthour metering devices, both electronic and electromechanical.
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Section 2
A number of definitions were added.
Section 3
3.10.2.2.2 (Performance requirements) – Tightened the % errors for portable and reference standards at reference conditions including a specific voltage and current.
3.10.2.2.3 (Variation for reference condition) – Gave additional percent errors for Portable and Reference Maximum Percent Errors @ 23°C over the designed range of voltage and current.
Section 4
4.7.1 (Test conditions under performance requirements) – Adds some clarity for the calibration level of the meters prior to entering into testing.
4.7.2 (Accuracy tests – internal influences) – A host of changes in this section, including the addition of a 0.5% accuracy classification. Contact MET for all of the changes in this section.
4.7.3.15 (Insulation) – A few changes, including the addition of a requirement to disconnect components providing a path in parallel with the insulation to be tested.
4.7.3.17 (Effect of high voltage line surges) – Adds an allowance for performing the accuracy performance check once after the completion of both a ring wave test and combination wave test.
4.7.3.30 (Effect of operating temperature) – A few changes, including ramp timing change from 6 to 5 hours.
4.7.3.31 (Effect of relative humidity) – A couple changes, including specifying test current between light load and class amps (same as 4.7.3.30).
Section 5
A number of changes in this section, including:
- Restructuring to provide clarity, guidelines and generally better reflect updated practices within the industry for in-service and new meter deployment.
- A test plan must be in place for metering devices at various set intervals (periodic interval plan, variable interval plan or a statistical sampling plan).
- Provides details for corrective actions that must be taken for any metering device or group of metering devices failing to meet performance criteria.
- Added recommendations on test data that should be recorded for the annual performance test programs.
- An Acceptable Quality Limit or AQL of 1.0% or less will be used to develop the acceptance criteria for all metering devices.
- Service switches to fall under a statistical sampling plan.
- Performance tests for integrated communication devices.
Appendices
Appendix D (Periodic testing schedule) – Recommended periodic test program cleaned up to reference AMI meters specifically, and then all other meters.
Appendix F (Variable interval plan) – Includes an example of appropriate test rates based on failed meters.
Questions about the changes? Ask Pat, our meter approvals expert.
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