AS IEC 60060.2:2018 pdf free.High-voltage test techniques Part 2: Measuring systems.
According to the ISO/IEC Guide 98-3, the uncertainty of a measurement is determined by combining the uncertainty contributions of Type A and Type B (see 5.10, 5.11 and Annex A). The contributions are obtained from measurement results, from manufacturers’ handbooks, calibration certificates and from estimating reasonable values of the influence quantities during the measurement. For example influence quantities mentioned in clause 5 include temperature and proximity effects. Others, like limited resolution of the measuring instrument, may be added if necessary.
NOTE 2 The resolution of a measuring instrument, e.g. one with few significant digits, may be a significant source of uncertainty.
During the actual voltage test, it is usually necessary to consider additional influencing quantities, apart from the calibration uncertainty of the scale factor stated in the calibration certificate, in order to obtain the uncertainty of measurement of the test voltage value.
Some guidance on determining uncertainty contributions, that need to be considered, and on their combination is given in Clause 5 and Annexes A and B. The uncertainty shall be given as the expanded uncertainty for a coverage probability of approximately 95 % corresponding to a coverage factor k=2 under the assumption of a normal distribution.
NOTE 3 In this International Standard, the uncertainties of the scale factor and of voltage measurement (5.2 to
5.10) are expressed by the relative uncertainties instead of the absolute uncertainty normally considered in the
ISO/IEC Guide 98-3. The direct application of the ISO/IEC Guide 98-3 and consideration of the absolute
uncertainties are shown in 5.11 for time parameters as well as in Annexes A and B.
5 Tests and test requirements for an approved measuring system and its com ponents
5.1 General requirements
The assigned scale factor of the measuring system shall be determined by calibration according to the specified performance tests. The assigned scale factor is a single value for the assigned measurement range. If necessary, several assigned measurement ranges with different scale factors may be defined.
For an impulse measuring system, the performance tests also show that its dynamic performance is adequate for the specified measurements and that the level of any interference is less than the specified limits.
Due to the large size of the equipment and the real environmental conditions, the calibration should preferably be performed on site by comparison with a reference measuring system.
Smaller size measuring systems or their components may be transported to another laboratory for calibration in an arrangement that simulates the operating conditions, provided that the interference test, when specified, is performed in the test facility of the user.
If a converting device is sensitive to proximity effects, the range of clearances where the assigned scale factor is valid shall be determined and entered in the record of performance. One or more ranges of clearances and respective scale factors may be assigned.
The scale factor of a measuring system shall be determined in the assigned measurement range, preferably by comparison with a reference measuring system. However, as reference measuring systems are not always available at higher voltages, the comparison may be made at voltages as low as 20 % of the assigned measurement range, provided that linearity has been determined from this point up to the limit of the assigned measurement range. One of the methods given in 5.3 shall be used for this extension.
All equipment used in establishing the scale factors of measuring systems shall have calibrations traceable to national and/or international standards.AS IEC 60060.2 pdf donwload.