IEC 62058-21 pdf download

IEC 62058-21 pdf download Electricity metering equipment (AC) – Acceptance inspection – Part 21: Particular requirements for electromechanical meters for active energy (classes 0,5, 1 and 2)
1 Scope
This part of IEC 62058 specifies particular requirements for acceptance inspection of newly manufactured direct connected or transformer operated electromechanical meters for active energy (classes 0,5, 1 and 2) delivered in lots in quantities above 50. The method of acceptance of smaller lots should be agreed upon by the manufacturer and the customer.
The process described herein is primarily intended for acceptance inspection between the manufacturer and the purchaser.
NOTE It can also be used for other purposes, for example to support initial verification.
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
IEC 62058-1 1 :2008, Electricity metering equipment (a.c.) – Acceptance inspection – Part 11: General acceptance inspection methods
ISO/IEC GUIDE 98: 1 995, Guide to the Expression of Uncertainty in Measurement
3 Terms, definitions, symbols and abbreviations
For the purposes of this document, the terms, definitions, symbols and abbreviations of IEC 62058-1 1 apply.
4 Test conditions
4.1 Place of inspection
Subclause 5.1 5 of IEC 62058-1 1 applies.
4.2 Reference conditions
The tests shall be carried out under the following conditions:
Table 1 – Voltage and current unbalance for polyphase meters
4.3 Uncertainty of measurement of percentage error
The measuring process shall be such that the uncertainty of the measurement of the percentage error should not exceed 1 /5 th of the limit of percentage error for the given test point at reference conditions. For determining the uncertainty of measurement, see ISO/IEC GUIDE 98.
If the uncertainty exceeds this limit, then inspection by variables cannot be used. Only inspection by attributes will be possible, and the limits of percentage error shall be corrected using the following formula: U I e I e corr
where:
• ) cos , ( ϕ I e is the limit of percentage error for the given test point at reference conditions;
• U is the measurement uncertainty.
EXAMPLE If, for a given test point, the limit of percentage error at reference conditions is
% 2 ) cos , ( ± = ϕ I e ; and
U = 0,5 %; then
% 9 , 1 ) 5 , 0 0 , 2 5 / 6 ( ) cos , ( ± = − • ± = ϕ I e corr .
Instead of the original limit, this corrected limit applies.
Table 3 gives percentage error limits corrected with uncertainty of measurement, using the formula above.