9
Type VFI, Fluid-insulated Switchgear
INSTALLATION, OPERATION AND MAINTENANCE INSTRUCTIONS
MN285006EN March 2018
3. Fluid samples should only be extracted when fluid
temperatures are 59 ºF (15 ºC) or higher. Moisture
analysis results may not accurately reflect the amount
of moisture inside the switchgear if samples are
extracted when the fluid is below this temperature.
4. The container temperature must be equal or
greater than the ambient air temperature to prevent
condensation after opening the container.
5. Never sample fluid during inclement weather (rain,
sleet or snow). The fluid sample could be contaminated
by moisture.
6. Always use the drain plug and sampler located near
the bottom of the front plate of the tank to extract fluid
samples.
7. Use only approved, new fluid-resistant tubing (nitrile or
silicone rubber) for sampling the fluid. Use of previously
used tubing or incompatible materials can result in
contamination of the fluid sample. Tube ID required for
the fluid sampling valve is 5/16 inch.
8. The fluid sampling valve and cap should be “finger
tight”. Use lineman’s pliers or tongue and groove pliers
to loosen the cap and/or valve if needed. Fluid should
start to flow from the valve after 2 – 3 counterclockwise
turns.
otee:
N
Do not attempt to turn the valve more than 5
full turns. The valve will completely uncouple
after 8 turns and allow fluid to flow freely. If fluid
does not flow from the valve after 5 turns and
the tank has been de-pressurized, re-tighten the
valve, and contact the manufacturer for further
instructions.
9. Using a disposable container (not the container that will
be sent to the lab), extract one quart of fluid from the
sample valve and discard it as waste.
10. Use only glass or extruded metal (solderless) containers
to store fluid for laboratory analysis. Plastic containers
must not be used as water vapor can permeate through
plastic and alter the results.
11. If dissolved gas analysis is required, the sample must
be collected using a glass syringe designed for this
purpose.
12. Label the sample container with the switchgear serial
number, sample date and temperature at the time of
extraction.
13. Rinse sample container with fluid before extracting a
sample. Fill sample container with fluid to 1/3 of the
container volume, rinse and discard rinse fluid.
14. Always fill sample containers to the top to prevent
ambient air from altering the moisture content of
the sample. Leave about one inch of air space in the
container to account for thermal expansion.
15. Retighten sampling valve to “finger tight” plus a 1/4
turn. Reinstall cap, and leave it “finger tight”.
16. Upon completion of sampling, recheck the switchgear
fluid level, and add fluid if required.
Fuid fill guidelines
The fluid level indicator sight gauge on the front plate of
the switchgear provides a convenient method to check fluid
levels. The indicator provides the correct level for fluid at
68 °F (20 °C).
If the fluid level is low, use the following procedure to add
dry insulating fluid to fill the unit to the correct level:
1. De-energize and ground the switchgear prior to fluid
filling.
2. Use only insulating fluid that complies with ASTM
D3487 (latest revision). The fluid must have a
minimum dielectric strength of 30 kV when tested
per ASTM D877. Never use fluid that contains PCBs
(Polychlorinated Biphenyls).
3. Use only transfer equipment that uses insulating fluid
resistant materials for hoses, seals, valves, pumps, etc.
Failure to use proper transfer equipment can result in
contamination of the fluid.
4. When adding fluid, use the fluid fill plug located on the
front plate of the unit.
5. Avoid getting gas bubbles in the fluid during filling. Gas
bubbles in the fluid can reduce the dielectric strength.
6. When filling is complete, check the fluid level gauge to
verify that the fluid is filled to the correct level. Allow
at least one hour for gas bubbles to dissipate prior to
energizing the unit.
7. Install plug and energize the unit.
8. Record the date and the amount of fluid needed to
re-fill the unit; retain information with the permanent
maintenance record of the unit.
Fluid testing
The insulating fluid in this equipment has been tested to
meet the requirements of ASTM D3487, and it has been
processed to remove moisture and dissolved gases. It must
be tested on a regular basis in order to ensure that it meets
those requirements.
Two types of fluid tests are required to evaluate and
maintain the quality of the insulating fluid. They are general
fluid tests and dissolved gas analysis.
General fluid tests
The general fluid test requirements are taken from IEEE
Std C57.106™-2002
IEEE Guide for Acceptance and
Maintenance of Insulating Oil in Equipment
. The required
fluid tests and acceptable limits for service-aged fluid are
shown in
Table 2
.
Fluid test results that do not meet the requirements may
indicate a problem with either the fluid or the unit. Contact
your Eaton representative for technical assistance.
