TRANSFORMER OILS TESTING OF NEW OIL
PROPERTIES BASIC INFORMATION
Testing Of Transformer Oil As
Recommended In IEEE Std C57.106-2002
When mineral insulating oil specified
to conform to ASTM D3487-00 is received, it should be tested to
verify conformance with ASTM D3487-00. Testing of the oil for full
conformance of all property requirements of ASTM D3487-00 is only
justified under circumstances determined by the purchaser.
As a minimum, it is recommended that
the purchaser require the supplier to provide a certified set of
tests for the oil that demonstrate that the oil, as shipped, met or
exceeded the property requirements of ASTM D3487-00.
For those circumstances where a full
set of tests according to ASTM D3487-00 are not justified, it is
recommended that, at a minimum, the tests shown in Table 1 of this
guide be considered. The purchaser of the oil should conduct tests
sufficient to satisfy concerns regarding conditions of shipment that
might result in non conformance to ASTM D3487-00 property
requirements.
Table 1 lists several of the more
important tests with values that should help in the decision
regarding acceptance of the new mineral insulating oil.
Insulating oil is ordinarily shipped in
three types of containers: drums or totes, tank trailers, and rail
cars. Rail cars are usually under the control of the supplier and
dedicated to insulating oil shipment, so they tend to be the
cleanest.
Highway trailers are used to transport
many different chemical products as well as insulating oil; these
trailers are therefore subject to chemical contamination. Special
cleaning and drying procedures may be necessary.
If problems are encountered, check the
history of the shipping containers to see that they have been cared
for properly. It is recommended that the purchaser require the
delivery of oil in containers that are properly cleaned to guarantee
delivery of oil conforming to ASTM D3487-00.
Drums and totes are the least desirable
method of insulating oil transport but may be necessary for small
purchases. Drums and totes should be stored under cover to prevent
contamination by moisture.
Before processing, it is necessary to
check the quality of the oil in each drum or tote or after blending
the oil in a large tank. Each tank load or each shipping unit of oil
as received at the customer’s site should undergo a check test to
determine that the electrical characteristics have not been impaired
during transit or storage.
Table 1 contains a list of recommended
acceptance tests for shipments of mineral insulating oil as received
from the supplier. Some users may not wish to perform all these
tests; however, as a minimum, dielectric strength and dissipation
factor (power factor) as listed in Table 1 should be performed.
It is satisfactory to accept oils that
exhibit characteristics other than those described by the values in
Table 1, providing that the users and the suppliers are in agreement.
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