AS 62053.22:2018 Electricity metering equipment (ac)— Particular requirements
7.2 Influence of short-time overcurrents
Short-time overcurrents shall not damage the meter. The meter shall perform correctly when back to its initial working condition and the variation of error at rated current and unity power factor shall not exceed 0,05 %.
The test circuit shall be practically non-inductive and the test shall be performed for polyphase meters phase-by-phase.
After the application of the short-time overcurrent with the voltage maintained at the terminals,the meter shall be allowed to return to the initial temperature with the voltage circuit(s) energized (about 1 h).
The test shall be carried out as follows: after the voltage circuits have been energized at reference voltage for at least 2 h without any current in the current circuits, the maximum current shall be applied to the current circuits. The meter error shall be measured at unity power factor immediately after the current is applied and then at intervals short enough to allow a correct drawing to be made of the curve of error variation as a function of time. The test shall be carried out for at least 1 h, and in any event until the variation of error during 20 min does not exceed 0,05 %.
8 Accuracy requirements
Tests and test conditions given in IEC 62052-1 1 apply.
8.1 Limits of error due to variation of the current
When the meter is under the reference conditions given in 8.5, the percentage errors shall not exceed the limits for the relevant accuracy class given in Tables 4 and 5.
If the meter is designed for the measurement of energy in both directions, the values in Table 4 and Table 5 shall apply for each direction.
The difference between the percentage error when the meter is carrying a single-phase load and a balanced polyphase load at rated current I n and unity power factor shall not exceed 0,4 % and 1 ,0 % for meters of classes 0,2 S and 0,5 S respectively.
NOTE When testing for compliance with Table 5, the test current should be applied to each measuring element in sequence.
8.2 Limits of error due to influence quantities
The additional percentage error due to the change of influence quantities with respect to reference conditions, as given in 8.5, shall not exceed the limits for the relevant accuracy class given in Table 6.