AS 62053.21:2018 Electricity metering equipment (ac)— Particular requirements
8.2.3 Tests of the influence of d.c. and even harmonics
The tests of the influence of direct current and even harmonics shall be made with the circuit shown in Figure A.1 or with other equipment able to generate the required waveforms, and the current waveforms as shown in Figure A.2.
The variation in percentage error when the meter is subjected to the test waveform given in Figure A.2 and when it is subjected to the reference waveform shall not exceed the limits of variation given in Table 8.
NOTE The values given in the figures are for 50 Hz only. For other frequencies the values have to be adapted accordingly.
8.2.4 Continuous magnetic induction of external origin
The continuous magnetic induction may be obtained by using the electromagnet according to annex B, energized with a d.c. current. This magnetic field shall be applied to all accessible surfaces of the meter when it is mounted as for normal use. The value of the magneto-motive force applied shall be 1 000 At (ampere-turns).
8.3 Test of starting and no-load condition
For these tests, the conditions and the values of the influence quantities shall be as stated in 8.5 except for any changes specified below.
8.3.3 Starting
The meter shall start and continue to register at the starting current values (and in case of polyphase meters, with balanced load) shown in Table 9.
If the meter is designed for the measurement of energy in both directions, then this test shall be applied with energy flowing in each direction.
8.5 Accuracy test conditions
To test the accuracy requirements, the following test conditions shall be maintained:
a) the meter shall be tested in its case with the cover in position; all parts intended to be earthed shall be earthed;
b) before any test is made, the circuits shall have been energized for a time sufficient to reach thermal stability;
c) in addition, for polyphase meters:
– the phase sequence shall be as marked on the diagram of connections;
– the voltages and currents shall be substantially balanced (see Table 1 0).