IEC 62059-32-1:2011 pdf free download – Electricity metering equipment – Dependability
The MUT shall be mounted as for normal operation，with all covers and terminal covers inplace. The ability of the MUT to transfer heat by thermal radiation shall be minimised. Fordetails, see lEC 6o068-2-2,6.3.
The MUT shall be connected as specified by the manufacturer,using the cable type specifiedby the manufacturer.The length of the cables within the test chamber shall be 1 m each. Thecross-section shall be selected so that the current density is between 3,2 A/mm2 and4 A/mm2. If this would result in a cable with a cross-section of less than 1,5 mm2， then acable with a cross-section of 1,5 mm2 shall be used.
In the case when the MUT is fitted with a load switch or when it is fitted with an overcurrenttripping device or residual current device,such devices shall be disabled for this test. lt shallbe confirmed that it is possible to calculate the energy consumption during the test using themeter register.
NOTE 1 The instructions of the manufacturer should be followed.
NOTE 2The reason for this requirement is that for example in the case of pre-payment meters, a test running for1 000 h would require huge amounts of credit. An overcurrent load switch might trip when tested for long periods at1max.
The MUT is introduced into the chamber，which is at the temperature of the laboratory. Theload specified above is then applied, and the meter is checked to ascertain whether it iscapable of functioning in accordance with the relevant specification.
lf necessary, a test shall be performed to determine if the test facility fulfils the requirementsof a low air velocity chamber or not. See lEC 60068-2-2,4.2.
The temperature is then adjusted to the test temperature. The rate of change of thetemperature within the test chamber shall not exceed 1 k per minute,averaged over a periodof not more than 5 min.
After temperature stability of the MUT has been reached，it is exposed to the conditionsspecified above for the specified duration.
NOTE 3 Temperature stability is reached，when the variation of percentage error at lma during 20 min does notexceed 1/5th of the limit of percentage error at reference conditions,specified in the relevant standard. This maybe determined using the test output and a reference standard meter, or by applying a stable load and measuringthe frequency of the test output pulse stream.
7.2.3Test using a reference meter of the same type as the MUT
In this case, the reference meter shall be of the same type and shall have the same referencevalues as the MUT.
NOTE 1 lt is assumed,that the behaviour of the MUT and the reference meter in the presence of influencequantities and disturbances is similar.
NOTE 2 Special care should be taken to ensure that the load on the reference meter and the MUT is the same. lnthe case of meters, where the voltage and current circuits cannot be separated, the voltage circuits of the MUT andthe reference meter should be supplied via appropriate multi-secondary voltage transtormers，so that the testconditions are met.