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ASTM D 1816-04
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ASTM D 877 A & B
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BS EN 60156
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CEI EN 60156
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IEC 60156 1995-05
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IRAM 2341-72
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JIS C2101-99 (M) & (S)
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PA SEV EN 60156
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UNE EN 60156
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NF EN 60156
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SABS EN 60156
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VDE 0370 Part 5
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AS1767.2.1
A critical factor with respect to field testing of oil is its temperature, because samples from a transformer taken shortly
after switch off can be many degrees hotter than equivalent room temperature laboratory tests performed at 20 ºC to
23 ºC. The OTS instruments measure the oil temperature during the test so that temperature correction can be applied
to results.
NB:
Certain standards require field tests to be performed between 20 ºC and 30 ºC.
Applications
The oil test set is used for determining the dielectric strength of high voltage insulating liquids, such as the insulating
oils used in transformers, switchgear and other electrical apparatus. The dielectric breakdown voltage is a measure
of the insulating ability of a liquid to withstand electrical stress. Contaminants such as cellulosic fibres, conducting
particles, dirt, and water reduce breakdown voltage of an insulating liquid. A low result indicates the presence of one
or more of these contaminants.
The test set is fully automatic. The operator has simply to prepare the test vessel, load it with sample oil, place it
in the test chamber, select the appropriate specification for the tests and then start the test sequence. The test set
automatically carries out the sequence of tests as defined by the pre-selected national specifications. Oil testing
specifications, for which the sets are pre-programmed, are as follows:
