Changes to Measurement Canada calibration program for electricity standards
Calibration of electricity standards
Starting on September 4, 2012, the calibration of electricity standards will include an uncertainty value associated with the measurement process that will include a standard uncertainty and an associated confidence interval. In order to provide this service, calibration procedures have been updated to require that measurement errors and uncertainties be established on the basis of five repeated runs.
In addition to the reporting of uncertainties, Measurement Canada has also standardized the set of test points which will be assessed for errors. These test points have been established by Measurement Canada electricity specialists on the basis of data gathered relating to the calibration and certification of electricity meter calibration consoles. The test points identified will cover the majority of test points required to calibrate an electricity meter calibration console. Some of the less common test points which were previously included in calibrations will no longer be included.
Impact on clients
There will be an impact on the costs associated with the certification and calibration of electricity standards. The five repetitions required to establish calibration uncertainties will triple the time needed to carry out certification. Our clients will notice increased costs associated with the calibration and certification of electricity standards commensurate with the increased time required to provide this service.
In 2009, Measurement Canada released revision 1 of S-S-02—Measurement Uncertainty and Meter Conformity Evaluation Specifications. This revision was an update to the document originally developed in 2005, which established specifications relating to the determination and use of measurement uncertainty for measurement standards. In addition to this document, several other documents relating to sampling inspections and sampling plans have also been released.
In keeping with the policies established by the above-referenced documents, Measurement Canada also established procedures for the certification of measuring apparatus. The following documents relating to the certification of electricity meters were developed in early 2009 and were posted on Measurement Canada's website in December 2011:
- EL-ENG-09-01 — Procedure for uncertainty determination for calibration consoles
- EL-ENG-09-02 — Uncertainty determination of electricity meter types
- EL-ENG-09-03 — Uncertainty determination - electricity meter verification tests
These documents were initially developed by a Canadian Electricity Association and Measurement Canada joint workgroup, which was tasked with updating acceptance sampling requirements for electronic electricity meters. In these documents, factors contributing to uncertainty of measurement were identified. As the majority of electricity meters are verified using calibrated and certified electricity meter calibration consoles, the uncertainties associated with the calibration of calibration consoles are established by the procedure outlined in EL-ENG-09-01. In section 4.6 of this document, the reference standard is identified as a source of uncertainty. The uncertainty of the standard is required to be provided by the certification and calibration process for the standard. Measurement Canada has updated its certification and calibration programs for electricity reference standards accordingly.
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