Required Tools; Required Material; Oil; Oil Conservator - ABB UCL Installation And Commissioning Manual

1.2 Required tools

– Standard set of open-end wrenches (up to 24 mm)
– Standard set of sockets (up to 24 mm)
– Standard set of screwdrivers
– Socket handle
– Set of pliers, including cutting pliers
– Dynamometric wrench, 5-85 Nm
– Sliding caliper
– Allen key sockets, 2–10 mm
– Pipe wrench
– Bottom valve key (delivered with the tap-changer)
– Lifting device, article no. LL 136 016-D
– Special hand crank for operating the tap-changer on the
bevel gear, article no. LL 117 016-M
– Hack saw (only for installation)
– File
– Folding ruler/tape measure
– Air pump with hose, pressure gauge (0–250 kPa) and
connection with internal thread R 1/8"
– Container, 50 liters
– Small oil pump with connection to the oil valve. (For
connection size, see the dimensional drawing for the tap-
changer.)

1.3 Required material

– Rags for cleaning
– Single-phase diagram for tap-changer
– Gasket for transformer flange
– Insulating paper
– Insulating bushings
– Wooden block as spacer
– Grease (ball bearing grease) GULF-718 EP, Mobil
Grease 28, SHELL Aero Shell Grease 22 or similar
– Oil, see Section 1.4
– Dimensional drawing for the tap-changer for connection
dimensions of the oil valve
– Flange for connection to the oil conservator flange when
filling under vacuum; see Fig. 38.
– Oil valves for connection to flange with dimensions
according to Fig. 42. Can be ordered from ABB.
– Equipment for oil filling
– Sealing tape
– Maintenance guide for tap-changer
– Circuit diagram the motor-drive mechanism
– Oil filter (when there is a common conservator for both the
transformer and the tap-changer, this can be ordered from
ABB).
12 Installation and commissioning guide UCL/VUCL | 1ZSC000562-AAZ en

1.4 Oil

The oil quality should be I -30° according to IEC 60296:2012,
and comply with IEC 60422:2008. Upon commissioning, the
break-down value should be at least 40 kV/2.5 mm according
to IEC 60156.
Type designation Oil weight (kg)
(The oil for the conservator is not included.)
UCL.., VUCL.. 380/... 260
UCL.., VUCL.. 650/... 300
UCG.., VUCG.. 1050/... 340
Table 1. Weight of oil in kg.
An UCL.B/VUCL.B requires twice and UCL.T/VUCL.T
three times the amount specified above since
they have two and three diverter switch housings
respectively.
WARNING
Do not energize the transformer until oil has been
filled according to Chapter 6.

1.5 Oil conservator

The tap-changer must be connected to an oil conservator.
ABB recommends using a separate conservator for the tap-
changer with both the oil and air side separated from the main
conservator of the transformer.
The volume of the conservator should be such that there
is still oil in the conservator even at the lowest expected
oil temperature, and such that no flooding can occur at
the expected highest oil temperature. Even tap-changers
consisting of more than one unit require only one conservator.
A suitable dimension of the tube for connection to the
conservator is an inner diameter of approximately 20 mm.
The tube should be inclined at least 3 degrees to avoid
gas pockets in the tube. A valve in the connection to the
conservator is recommended.
The conservator must be equipped with a breathing device
that does not allow moist air into the conservator and that
permits the gas to dissipate.
The conservator should also be equipped with an oil
level indicator, and an alarm contact for low oil level is
recommended.