Howard Small Power - Manual (Page 8)

Document 2.4.54 Revision 0
July 2006 Small Power Substation Transformers
8
3. Pressurize the headspace to 4 PSIG and
check for fluid leaks. This pressure should be
maintained for at least four hours.
When the internal inspection is complete, reseal the
tank and refill with fluid (if any was removed prior to
inspection). The gas space should be filled with dry
air or dry nitrogen to 2 PSIG. Contact the Howard
Substation Transformer Division if any internal damage
is found during the internal inspection.
Installation of Detachable Radiators
When radiators are shipped detached, they should be
installed according to the instructions below.
1. Verify that all valves on the tank are in the
closed position.
2. Remove shipping plates from the valves on the
tank and from the radiator flanges. Take care
not to damage gaskets.
3. Inspect for moisture and contamination
inside the radiator headers. Contact the
Howard Substation Transformer Division if any
contamination is found.
4. Clean all mating surfaces on the tank valves
and radiator flanges and apply a small amount
of petroleum jelly to the gaskets on the tank
valve flanges to hold them in place during
installation of the radiators.
5. Lift the radiators into position using the lifting
eyes on top of the radiators and align holes
in the radiator flanges with holes in the valve
flanges. If fans are provided, attach the
radiators having fans first, then attach the
other radiators.
6. Insert bolts in the top and bottom flanges with
bolt heads adjacent to the transformer tank.
7. Tighten bolts evenly alternating across corners
until metal-to-metal tightness is achieved at all
four corners of each flange
Filling Installed Radiators with Fluid
Follow the steps below to fill installed radiators with
insulating fluid.
!
DANGER: TRANSFORMER OIL SHOULD
ALWAYS BE HANDLED AS A FLAMMABLE
FLUID. UNDER SOME CONDITIONS, SEALED
TRANSFORMER TANKS MAY ACCUMULATE
EXPLOSIVE GASES AND THE HANDING OF
TRANSFORMERS MAY GENERATE STATIC
ELECTRICITY. SAFETY PRECAUTIONS BEFORE OIL-
FILLING OR FILTERING SHOULD INCLUDE PURGING
ALL GAS SPACES WITH NITROGEN, GROUNDING
THE TRANSFORMER, ALL BUSHINGS, AND ALL OIL
HANDLING EQUIPMENT. FAILURE TO DO SO COULD
RESULT IN SEVERE PERSONAL INJURY, DEATH, OR
EQUIPMENT DAMAGE.
!
WARNING: TRANSFORMERS SHOULD
NOT BE LEFT UNDER VACUUM EXCEPT
DURING THE VACUUM FILLING OPERATION. THE
TANK SHOULD BE UNDER POSITIVE PRESSURE
DURING PERIODS OF RAIN OR HIGH HUMIDITY
IN ORDER TO PREVENT MOISTURE FROM BEING
DRAWN INTO THE TANK. FAILURE TO FOLLOW
THESE PRECAUTIONS COULD RESULT IN SEVERE
PERSONAL INJURY, DEATH, OR EQUIPMENT
DAMAGE.
During the process do not allow the fluid level to drop
below the top of the core and coil assembly. If the
fluid level in the transformer becomes too low, stop
the radiator filling procedure and add fluid to the tank
before completing the filling process.
1. Loosen the top header plugs and slowly open
the bottom radiator valves one at a time to
start the flow of fluid.
2. Add fluid to the tank if necessary during the
process to maintain the proper fluid level in the
tank.
3. After the radiators are filled, open the top
radiator valves.
4. Remove the top header plugs and reinstall
them using Teflon pipe thread tape.
5. Ensure that top and bottom radiator valves on
each radiator are in the full “OPEN” position.
6. Observe the fluid level gauge and ensure that
the fluid level is correct. If the level is low, add
fluid to the tank.