2. This Technical Guide has been produced to allow transformer manufacturers, and their
designers and engineers, access to all the technical information required to assist them in
their selection of the appropriate on-load tap-changer and motor-drive mechanism.
The technical information pertaining to on-load tap-changers and motor-drive mecha-
nisms manufactured by ABB has been divided and is contained in separate documents,
with one document for each type.
The information provided in this document is intended to be general and does not cover
all possible applications. Any specific application not covered should be referred directly
to the supplier, or its authorized representative.
ABB makes no warranty or representation and assumes no liability for the accuracy of
the information in this document or for the use of such information. All information in this
document is subject to change without notice.
Manufacturer’s declaration
The manufacturer ABB AB
Components
SE-771 80 LUDVIKA
Sweden
Hereby declares that
The products On-load tap-changers, type UC and VUC
with motor-drive mechanisms, types BUE and BUL
comply with the following requirements:
By design, the machine, considered as component on a mineral oil filled power transformer, complies
with the requirements of
• Machinery Directive 89/392/EEC (amended 91/368/EEC and 93/44/EEC) and 93/68/EEC (mark-
ing) provided that the installation and the electrical connection be correctly realized by the manu-
facturer of the transformer (e.g. in compliance with our Installation Instructions)
and
• EMC Directive 89/336/EEC regarding the intrinsic characteristics to emission and immunity levels
and
• Low Voltage Directive 73/23/EEC (modified by Directive 93/68/EEC) concerning the built-in motor
and apparatus in the control circuits.
Certificate of Incorporation:
The machines above must not be put into service until the machinery into which they have been
incorporated have been declared in conformity with the Machinery Directive.
Date 2008-03-15
Signed by .........................................................................
Folke Johansson
Title Manager of Division for Tap-Changers
3. Contents
General information...................................................................... 5
Design principles.......................................................................... 8
On-load tap-changer....................................................................................8
Diverter switches..........................................................................................8
Conventional diverter switch.
...................................................................8
Diverter switch with vacuum interrupters.
................................................8
Tap selector.............................................................................................10
Design differences over the UC range of on-load tap-changers.............10
Diverter switch housing and top section .................................................12
Painting..............................................................................................12
Operating mechanism.............................................................................12
Transition resistors..................................................................................13
Special applications, load conditions and environments.........................13
Special designs......................................................................................13
On-line oil filtration (for diverter switch with arc quenching in oil only)....13
Motor-drive mechanism................................................................................14
Type BUE................................................................................................14
Type BUL.
................................................................................................14
Accessories..................................................................................................14
Tap-changer principles of operation............................................. 15
Switching sequence, UC .............................................................................15
Switching sequence, VUCG.........................................................................16
Type of regulation.........................................................................................18
Linear switching (type L) ........................................................................18
Change-over selector for plus/minus switching (type R).........................18
Change-over selector for coarse/fine switching (type D) ........................18
Type of connection.......................................................................................19
Three-phase star point (N)......................................................................19
Single-phase (E).
.....................................................................................19
Three-phase delta (B).............................................................................19
Three-phase delta fully insulated (T).
......................................................19
Auto transformer (T)................................................................................19
Tap-changer characteristics and technical data........................... 20
Type designation..........................................................................................20
Maximum number of positions................................................................21
Diverter switches..........................................................................................21
Tap selectors................................................................................................22
Possible combinations of diverter switches and tap selectors.
................22
Enforced current splitting.
.............................................................................22
In position................................................................................................22
During operation.
.....................................................................................23
Rated phase step voltage.
............................................................................24
Coarse fine regulation leakage inductance switching.............................26
Contact life.
...................................................................................................26
Standards and testing..................................................................................28
Rating plate..................................................................................................28
Insulation levels............................................................................................28
Withstand voltages.......................................................................................31
UCG and VUCG with tap selector C.
.......................................................31
UCG and VUCG with tap selector I.........................................................31
UCG and VUCG with tap selector III unshielded version........................32
UCG and VUCG with tap selector III shielded version............................32
4. UCL with tap selector III unshielded version...........................................33
UCL with tap selector III shielded version...............................................33
UCD with tap selector III unshielded version.
..........................................34
UCD with tap selector III shielded version.
..............................................34
UCC with tap selector IV.........................................................................35
Short-circuit current strength........................................................................36
Highest phase service voltage across the regulating winding .....................37
Rated through-current..................................................................................37
Occasional overloading................................................................................37
Oil temperature.
............................................................................................38
Coarse/fine regulation leakage inductance switching.
..................................39
Tie-in resistor and tie-in resistor switch........................................................40
Installation and maintenance.
....................................................... 42
On-load tap-changer....................................................................................42
Installation...............................................................................................42
Drying......................................................................................................42
Weights...................................................................................................42
Oil filling .
.................................................................................................44
Maintenance.
...........................................................................................45
Pressure..................................................................................................45
Accessories and protection devices.............................................................45
Motor-drive mechanism................................................................................46
Design.....................................................................................................46
Installation...............................................................................................46
Maintenance.
...........................................................................................46
Operating shafts......................................................................................46
Dimensions.
..................................................................................................48
Type UCG/C and VUCG/C......................................................................48
Type UCG/I and VUCG/I.
.........................................................................49
Type UCG/III and VUCG/III.
.....................................................................50
Type UCL/III.
............................................................................................52
Type UCD/III............................................................................................55
Type UCC/IV.
...........................................................................................57
Oil conservator........................................................................................59
Appendices: Single-Phase Diagrams........................................... 60
Appendix 1: Single-phase diagrams for UCG/C......................................60
Appendix 2: Single-phase diagrams for UCG/I.
.......................................65
Appendix 3: Single-phase diagrams for UCG/III, VUCG/III, UCL/III
and UCD/III.
.............................................................................................72
Appendix 4: Single-phase diagrams for UCC/IV.....................................79
5. 5
1ZSE 5492-105 en, Rev. 8
General information
When the on-load tap-changer operates, the insulating oil will be contam-
inated. To avoid contamination of the transformer oil, the diverter switch
has its own housing separate from the rest of the transformer. The tap
selector, which is mounted beneath the diverter switch housing, consists
of the fine tap selector and usually also of a change-over selector. The
operating principle for the UC and VUC range of on-load tap-changers is
called the diverter switch principle.
The UC types of on-load tap-changers are usually mounted inside of the
transformer tank, suspended from the transformer cover. Power to oper-
ate the on-load tap-changer is supplied from the motor-drive mechanism,
which is mounted on the outside of the transformer. The power is trans-
mitted by means of shafts and bevel gears.
The UC types of on-load tap-changers come in a wide range of models
with a rating suitable for every application.
Transformer cover
On-load tap-changer
Oil conservator
Motor-drive mechanism
Shaft
Bevel gear
Shaft
Transformer tank
Fig. 1. Main parts, on-load tap-changers types UC and VUC.
Diverter switch
Tap selector
6. 6 1ZSE 5492-105 en, Rev. 8
Cover
Lifting eye
Top section
Shielding-ring
Current terminal
Bottom section
Valve for use at
processing
Connections from
the tap selector
Plug-in contacts
Insulating
cylinder
Diverter switch
Oil draining tube
Flange for connection
to gas operated relay
Intermediate gear
Driving disc for the
diverter switch
Guiding pins
Fixed and moving
contacts
Transition resistors
Shielding-ring
Insulating shaft
Bevel gear with
position indicator
Buffer springs
Diverter switch housing
Fig. 2. On-load tap-changer type UCG.
8. 8 1ZSE 5492-105 en, Rev. 8
Design principles
On-load tap-changer
When the on-load tap changer operates, the oil is contaminated. UC with
conventional arc quenching in oil contaminates the oil heavily while VUC
with arc quenching in vacuum interrupters only contaminates slightly due
to current commutation sparks and heat dissipation from the transition
resistors. To avoid contamination of the transformer oil the on-load tap-
changer is built in two separate sections, the diverter switch, which has
its own housing, and the tap selector. The tap selector is mounted below
the diverter switch housing and the complete unit is suspended from the
transformer cover.
VUC and UC are of the diverter switch type. UC works according to
the flag cycle principle and VUC works according to the pennant cycle
principle.
Diverter switches
Two different types of diverter switches are available, the conventional
type with arc quenching in oil and the new type with vacuum interrupters.
The diverter switch is of the high-speed, spring-operated type with resis-
tors as transition impedance.
The diverter switches are equipped with plug-in contacts that automati-
cally connect it to the bushings in the diverter switch housing when the
switch is lowered into the housing. Guiding facilities keep the diverter
switch in correct position when lowering it into the housing. Mechanical
coupling to the motor-drive mechanism is automatically established when
the driving pin enters the slot in the driving disc.
The design and dimensioning of the diverter switches offer high reliability
and long life with a minimum of maintenance and easy inspection.
Conventional diverter switch
The diverter switch is designed as a system of moving and fixed contacts.
Movement of the moving contact system is controlled by a self-locking
polygon link system with a set of helical springs. The link system is robust
and has been carefully tested. The fixed contacts are placed on the sides
of the diverter switch, which are made of insulated board.
The current-carrying contacts are made of copper or copper and silver,
and the breaking contacts of copper-tungsten.
Diverter switch with vacuum interrupters
Combines all the advantages of the conventional type with improved
breaking capacity, increased contact life and reduced maintenance.
It works according to the pennant cycle, which gives the lowest complex-
ity and allows full power flow in both directions. A mechanical rectifier
ensures operation in only the direction that gives the lowest breaking
stresses and contact wear.
9. 9
1ZSE 5492-105 en, Rev. 8
Fig. 4. Examples of diverter switches UCG and VUCG.
The load is commutated from one tap to the other by aid of the vacuum
interrupters and auxiliary contacts. The auxiliary contacts are also able to
break the load current in the unlikely event of a vacuum interrupter failure
should occur.
In service position the current is transferred through the auxiliary contacts
and the vacuum interrupters. All current carrying contacts are made of
low resistance material.
The vacuum interrupters have a very long life time but yet mounted for
easy replacement when needed, for instance in industrial applications
when the number of operations might be extremely high.
The contact system is powered by a compact mechanical system with
integrated driving springs, mechanical rectifier, robust mechanical sys-
tem for vacuum interrupter actuating and geneva gears for operating the
auxiliary contacts.
All manufactured conventional UCGs can be easily replaced by the
vacuum diverter switch and gain benefit of the improvements made on
this type.
10. 10 1ZSE 5492-105 en, Rev. 8
Tap selector
Although the tap selector for the UC range of on-load tap-changer is
available in various sizes, all have similar functions with different ratings.
The fixed contacts are mounted around the central shafts. The moving
contacts are mounted on, and are operated by, the shafts in the center of
the selector. The moving contacts are connected, via current collectors, to
the diverter switch by means of paper insulated copper conductors.
Depending on the load current, the moving contacts have either one,
two, or more contact arms in parallel with one, two or four contact fingers
each. The fingers make contact at one end with the fixed contact, and
at the other with the current collector. The moving contacts slide on the
fixed contacts and the current collector rings, giving a wiping action which
makes the contacts self cleaning. This arrangement promotes good con-
ductivity and negligible contact wear.
Fig. 5. Tap selectors: size C and size III.
Design differences over the UC range of on-load tap-changers
The UC range of tap-changers consists of five diverter switches and four
tap selectors.
The diverter switches, from the smallest to the biggest type, are UCG,
VUCG, UCL, UCD and UCC. VUCG has arc quencing in vacuum, all oth-
ers have arc quencing in oil.
The VUCG diverter switch fits without modification in all UCG tap-chang-
ers as manufactured 1977 and later, which enables all UCG tap-changers
to be easily upgraded to vacuum technology.
11. 11
1ZSE 5492-105 en, Rev. 8
L (m)
3
2
1
UCG.N/C
VUCG.N/C
UCG.N/I
VUCG.N/I
650 kV
UCG.N/III
VUCG.N/III
650 kV
UCL.N/III
650 kV
UCD.N/III
650 kV
UCC.N
650 kV
Fig. 6. On-load tap-changers type UC, size comparison.
The tap selectors, from the smallest to the biggest type, are C, I, III and
IV. Tap selectors I and C can be combined with UCG and VUCG diverter
switches. Tap selector III can be combined with all diverter switches ex-
cept UCC. Tap selector IV can be combined with UCC only.
For correct selection, use this Technical Guide or the ABB selection pro-
gram “Compas”.
UCG is available in two versions (standard and short) and manages 200
– 300 MVA star connected transformers and up to approximately 500
MVA Auto transformers.
UCL manages star connected transformers up to 500-600 MVA and Auto
transformers up to 1000 MVA.
UCD and UCC manages star connected transformers >600 MVA and
>1000 MVA respectively. For winding connections where three single-
phase tap-changers are needed, each single phase of the UCD and UCC
must have it-s own motor-drive mechanism.
In tap selectors I and IV the fixed contacts are mounted on insulating
bars, whereas the C and III types use a complete, un-divided glass fibre
reinforced epoxi cylinder.
12. 12 1ZSE 5492-105 en, Rev. 8
Diverter switch housing and top section
The top section forms the flange that is used for mounting to the trans-
former cover, and for carrying the gear box for the operating shafts. The
top section includes a connection for the conservator pipe, draining and
filtering connections, an earthing terminal, the supervisory device, and
the cover with its gasket. The top section is available in two designs, one
for cover mounting and one for pre-mounting (yoke-mounting) on the
transformer’s active part.
The diverter switch housings have high quality sealings that guarantee
vacuum and overpressure-proof performance under all service condi-
tions. In case of material ageing after extremely long service the sealings
can be re-tightened.
The bottoms and heads of the cylinders are made of cast aluminium.
The driving shafts and bevel gears are placed beside the diverter switch
cylinders, thereby providing easy access to the diverter switches.
The bottom section has locating holes for the diverter switch, bearings,
brackets for the tap selector mounting and the current terminal for the
diverter switch. There is also a draining valve in the bottom which should
only be opened during the drying process of the transformer.
The top and bottom sections are fixed to a cylinder of glassfibre rein-
forced plastic. The bushings through the cylinder wall are sealed by O-
ring gaskets with elastic pressure. Each ready-made unit is tested under
vacuum and the outside is exposed to helium and checked for leaks with
the use of a helium gas detector.
Painting
The diverter switch housing top sections are finish coated with a blue-
grey colour, Munsell 5,5 B 5,5/1,25, corrosion class C3 acc. to SS-EN
ISO 12944-2. For the motor drives, the painting can be chosen between
primary coating corrosion class C3 or finish coated with a blue-grey
colour, Munsell 5,5 B 5,5/1,25, corrosion class C3 acc. to SS-EN ISO
12944-2.
Operating mechanism
The bevel gear, mounted on the top section flange transfers the drive
from the motor-drive mechanism, via the vertical shaft, to the intermedi-
ate gear for the diverter switch and the tap selector.
From the intermediate gear, a drive shaft transfers the energy to the di-
verter switch through an oil tight gland in the bottom of the diverter switch
housing. When the diverter switch is lowered into the housing (after
inspection), the drive is automatically re-connected by a system that en-
sures that the drive shaft and the guiding pin of the diverter mechanism is
correctly aligned.
The intermediate gear also drives the geneva gear of the tap selector, via
a free wheel connection. The geneva gear provides alternate movement
to the two vertical shafts of the tap selector.
The external drive shaft, that does not need to be removed during main-
tenance work, minimizes the risk for misalignment in the system. However
a mechanical end limit stop for the tap selector is available on request.
Special shaft systems are also available on request.
13. 13
1ZSE 5492-105 en, Rev. 8
Transition resistors
The transition resistors are made of wire and located above the diverter
switch contacts. The resistors are robust and designed to withstand the
lifetime of the mechanism under normal service conditions.
Special applications, load conditions and environments
Please contact the supplier for advisory in the following cases:
■
■ For special applications such as:
-
- Arc furnace
-
- HVDC
-
- Rectifiers
-
- Shunt reactors
-
- Series reactors
-
- Phase shifters
-
- Traction
-
- Industrial applications in general
-
- OLTCs working in parallel
■
■ In case of unusual load conditions such as overloads beyond IEC
60076-7, IEC 60354 or IEEE C57.131-1995, extreme inductive or
capacitive loads or loads beyond the given data in this document.
■
■ In case of service in extreme environments such as very high humid-
ity, very high or low temperatures, indoors, etc.
Special designs
On request, the UC and VUC tap-changers are also available for regula-
tion with bias winding and for Y/D regulation.
On-line oil filtration (for diverter switch with arc quenching in oil only)
On-line oil filtration is not required in any application and does not extend
lifetime of contacts, but can give benefits for OLTCs with arc quenching in
oil in certain applications such as:
■
■ Arc furnace applications (prolongs mechanical life and maintenance
interval and shortens maintenance time)
■
■ High voltage line end applications (maintains the high dielectric with-
stand of the insulating liquid)
■
■ Whenever short outage time is important when carrying out
maintenance
■
■ At any application with a high number of operations or high dielectric
stresses.
The on-line oil filtration works with continuous low flow filtration giving
the best filtration result, less risk of gas bubbles and requires less con-
trol equipment. Filter cartridges are easily replaced without taking the
transformer out of service. For further information about the oil filter, see
manual 1ZSC000562-AAA.
The filtration reduces the number of particles and keeps the moisture
level at a dielectric safe level.
14. 14 1ZSE 5492-105 en, Rev. 8
Motor-drive mechanism
The motor-drive mechanism provides the drive to allow the on-load tap-
changer to operate. Energy is provided from a motor through a series of
gears and out through a drive shaft. Several features are incorporated
within the mechanism to promote long service intervals and reliability.
There are two sizes of motor-drive mechanisms that can be used. If there
are any doubts about which type to select, please consult the supplier.
Type BUE
The BUE is intended for all on-
load tap-changers types UC
and VUC. For detailed opera-
tion description, see Technical
Guide for Motor-Drive
Mechanisms type BUE.
Fig. 7a. Motor-drive mechanism
type BUE
Type BUL
The BUL is intended for
on-load tap-changers types
UCG, VUCG and UCL at star
point or single-phase applica-
tions. However, when extra
space is required for optional
accessories the type BUE
might have to be selected
due to limited space in the
BUL. For detailed operation
description, see Technical
Guide for Motor-Drive
Mechanisms type BUL.
Fig. 7b. Motor-drive mechanism type BUL
Accessories
For a list of accessories available for both the on-load tap-changers and
the motor-drive mechanisms, consult the supplier.
15. 15
1ZSE 5492-105 en, Rev. 8
Tap-changer principles of operation
Switching sequence, UC
The switching sequence of the on-load tap-changer from position 6 to
position 5, is shown in the figures below.
The sequence is designated the symmetrical flag cycle. This means that
the main switching contact of the diverter switch, breaks before the tran-
sition resistors are connected across the regulating step. This ensures
maximum reliability when the switch operates with overloads.
At rated load the breaking takes place at the first current zero after con-
tact separation, which means an average arcing time of approximately
4-6 ms. The total time for a complete sequence is approximately 50 ms.
The tap change operation time of the motor-drive mechanism is approxi-
mately 5 s/step. (10 s for through-positions.)
Fig 8a. Position 6
Selector contact V con-
nects tap 6 and selector
contact H on tap 7. The
main contact x carries
the load current.
Fig. 8b
Selector contact H has
moved in the no-load
state from tap 7 to tap 5.
Fig. 8c
The main contact x has
opened. The load cur-
rent passes through
the resistor Ry and the
resistor contact y.
Fig. 8d
The resistor contact u
has closed. The load
current is shared be-
tween Ry and Ru. The
circulating current is
limited by the resistance
of Ry plus Ru.
Fig. 8e
The resistor contact y
has opened. The load
current passes through
Ru and contact u.
Fig. 8f. Position 5
The main contact v has
closed, resistor Ru is
bypassed and the load
current passes through
the main contact v. The
on-load tap-changer is
now in position 5.
16. 16 1ZSE 5492-105 en, Rev. 8
MVI
MC
RVI
TR
RC
x
v
MVI
MC
RVI
TR
RC
x
v
MVI
MC
RVI
TR
RC
x
v
Switching sequence, VUCG
By using an auxiliary contact system (MC, RC) in combination with the
vacuum interrupters (MVI, RVI) only two vacuum interrupters are required
per phase.
Fig. 9a shows the current path during normal operation, from x to the star
point (could also be to the next phase). When commuting the load from x
to v, the first part of the operation sequence is to open the main vacuum
interrupter (MVI) and hence let the current flow through the transition
resistor (TR), Fig. 9b. The main contact (MC) is then rotated (Figs. 9c and
9d) in order to connect to v. The main vacuum interrupter then closes,
leading to an associated circulating current driven by the difference in
voltage potential, Fig. 9e. In Fig. 9f, the transition resistor is disconnected
when opening the resistor vacuum interrupters (RVI). The load current is
now via the normal path from v to the star point. The resistor contact (RC)
is then rotated and put in position according to Fig. 9g. Finally, the se-
quence is completed and next service position is reached when the resis-
tor vacuum interrupter is closed, see Fig. 9h.
Fig. 9a.
Fig. 9b.
Fig. 9c.
17. 17
1ZSE 5492-105 en, Rev. 8
MVI
MC
RVI
TR
RC
x
v
MVI
MC
RVI
TR
RC
x
v
MVI
MC
RVI
TR
RC
x
v
MVI
MC
RVI
TR
RC
x
v
MVI
MC
RVI
TR
RC
x
v
Fig. 9d.
Fig. 9e.
Fig. 9f.
Fig. 9g.
Fig. 9h.
18. 18 1ZSE 5492-105 en, Rev. 8
Change-over selector for plus/minus switching (type R)
The change-over selector extends
the regulating range to twice the
voltage of the tapped winding, by
connecting the main winding to
different ends of the regulating
winding.
Fig. 11
Change-over selector for coarse/fine switching (type D)
In type D switching the change-
over selector extends the regu-
lating range to twice the voltage
of the tapped winding, by con-
necting or disconnecting the
coarse regulating winding.
Fig. 12
Reversing
Change-over selector
Change-over selector,
coarse/fine
Type of regulation
Linear switching (type L)
The regulating range is equal to the
voltage of the tapped winding. No
change-over selector is used.
Fig. 10
19. 19
1ZSE 5492-105 en, Rev. 8
Type of connection
Three-phase star point (N)
Only one unit is required for all three
phases. The transformers neutral
point is in the OLTC.
Single-phase (E)
Only one unit is required
Three-phase delta (B)
Two units required. Driven by a com-
mon motor-drive. One unit common
for two phases.
Three-phase delta fully insulated (T)
Three units required. Driven by a
common motor-drive.
Auto transformer (T)
Several configurations of auto trans-
formers exist. This example shows
the tap-changer in auto-tap.
20. 20 1ZSE 5492-105 en, Rev. 8
Tap-changer characteristics and technical data
Type designation
UC... Diverter switch with arc quenching in oil
VUC... Diverter switch with vacuum interrupters
Example UCGRE 650/700/C
Type of tap-changer
UC... Diverter switch with arc quenching in oil
VUC... Diverter switch with vacuum interrupters
Type of switching
L Linear
R Plus/Minus
D Coarse/Fine
Type of connection
N Three-phase star point (one unit)
E Single-phase (one unit)
T Three-phase fully insulated (three units)
B Three-phase delta (two units; single-phase and two-phase)
Impulse withstand voltage to earth
UCG, VUCG: 380 kV, 650 kV, 750 kV, 1050 kV
UCL: 380 kV, 650 kV, 750 kV, 1050 kV
UCD, UCC: 380 kV, 650 kV, 1050 kV
Maximum rated through-current
See tables for diverter switches and tap selectors respectively. The lowest rating of
the two determines the overall rating.
Tap selector size
C tap selector for UCG and VUCG only
I tap selector for UCG and VUCG only
III tap selector for UCG, VUCG, UCL and UCD
IV tap selector for UCC
UCG . . XXXX/YYYY/Z
VUCG . . XXXX/YYYY/Z
UCL . . XXXX/YYYY/Z
UCD . . XXXX/YYYY/Z
UCC . . XXXX/YYYY
21. 21
1ZSE 5492-105 en, Rev. 8
Maximum number of positions
Table 1. Maximum number of positions.
Type of switching Tap selector Max. number of positions
Linear C 14
I 18
III 22
IV 18
Plus/minus C 27
I 35
III 35
IV 35
Coarse/fine C 27
I 35
III 35
IV 35
Diverter switches
Table 2. Diverter switches.
Type Max. rated through-current
VUCG.N, B 700 A
VUCG.E, T 1600 A 3)
VUCG.N, B, short version 1)
600 A
VUCG.E, T, short version 1)
1000 A 3)
UCG.N, B 300, 500, 600 A
UCG.E, T 300, 500, 600, 1200, 1500 A
UCG.N, B, short version 1)
300 A
UCG.E, T, short version 1)
900 A
UCL.N, B 600, 900 A
UCL.E, T 600, 900, 1800, 2400 A
UCD.N 2)
1000 A
UCD.E 2)
1600 A
UCC.N 2)
1600 A
UCC.E 2)
1600 A
1)
Shorter diverter switch housings, see dimension drawings in this guide. See also limits in
Fig. 14.
2)
UCC and UCD requires one motor-drive mechanism for each OLTC unit.
3)
For currents higher than 800 A, please contact ABB.
22. 22 1ZSE 5492-105 en, Rev. 8
Tap selectors
Table 3. Tap selectors.
Type Connection Max. rated through-current Max impulse test
voltage across range
C N, B 400, 600 A 350 kV
E, T 400, 600, 700, 1050, 1200, 1500,
1600 A
350 kV
I N, B 600 A 300 kV 2)
E, T 600, 1200, 1500, 1600 A 300 kV 2)
III N, B 1000 A 550 kV 2)
E, T 1000, 1800, 2400 A 550 kV 2)
IV 1)
N, E 1600 A 500 kV
1)
UCC requires one motor-drive mechanism for each unit and is therefore not available in
connection B and T.
2)
Note that for certain positions, these values are lower. See Insulating levels.
Possible combinations of diverter switches and tap selectors
Diverter switch UCG, VUCG UCL UCD UCC
Tap selector C I III IV
Enforced current splitting
In certain applications, two or more poles of an on-load tap-changer, or
more than one on-load tap-changer can work in parallel. However, it is im-
portant to make this in a correct way. It differs between whether it should
work in position (not during operation) only or if it should operate during
operation.
In position
Enforced current splitting in position is used only between poles within
one on-load tap-changer for operation in one phase. It is used when hav-
ing a tap selector with a lower current rating than the diverter switch. By
having the same number of conductors through the regulating winding as
there are poles in the tap selector and connect each of them to one pole
of the tap selector, the rating for one pole times the number of poles can
be made use of. Otherwise a certain reduction in current rating has to be
done due to unequal current splitting between the poles.
23. 23
1ZSE 5492-105 en, Rev. 8
During operation
Enforced current splitting during operation can be used when the diverter
switch has a lower current rating than the tap selector or when two or
more on-load tap-changers work in parallel in the same phase.
By having the same number of conductors in parallel through the wind-
ings as there are poles or on-load tap-changers in parallel, parallel work-
ing conditions can be made to work. However, the impedance between
these parallel paths must be such that the current through any of the
poles or any of the on-load tap-changers must not exceed the rating of
any of them. The reason is that the poles in the diverter switch or the di-
verter switches do not operate at exactly the same time.
To achieve this impedance, it is normally required that the parallel con-
ductors are kept separated through both the regulating and the main
winding. However, the impedance between them must be calculated by
the transformer manufacturer in each case where enforced current split-
ting during operation should be made use of.
See also IEC 60214-2, paragraph 6.2.9 for information.
24. 24 1ZSE 5492-105 en, Rev. 8
Rated through-current (A)
Step
voltage
(V)
500
0
1000
1500
2000
2500
3000
3500
0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300
UCG.E,T
Short version
UCG.N,B
UCG.N,B
Short version
UCG.E,T
1400 1500
Rated through-current (A)
Step
voltage
(V)
500
0
1000
1500
2000
2500
3000
3500
0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600
VUCG.N,B
VUCG.N,B
Short version
VUCG.E,T
For currents higher than 800 A,
please contact ABB.
VUCG.E,T
Short version
Rated phase step voltage
The maximum permitted step voltage is limited by the electrical strength
and the switching capacity of the diverter switch. The rated phase step
voltage is a function of the rated through current as shown in the dia-
grams below.
For arc furnace transformers, only up to 75 % of the given step voltages
below are allowed. In case the current during electrode short circuits
exceeds twice the rated through-current, please contact the supplier for
advice.
UCG and VUCG in short version have a 220 mm shorter diverter switch
housing, see dimension drawings in this document. For short version,
there might be restrictions in applications other than network.
Fig. 13. Rated phase step voltage for type UCG.
Fig. 14. Rated phase step voltage for type VUCG.
25. 25
1ZSE 5492-105 en, Rev. 8
Rated through-current (A)
Step
voltage
(V)
500
0
1000
1500
2000
2500
3000
3500
0 200 400 600 800 1000 1400 1600
4000
4500
5000
UCL.N,B
UCL.E,T
1200 1800 2000 2200 2400 2600
UCL.N,B
UCL.N,B
Rated through-current (A)
Step
voltage
(V)
500
0
1000
1500
2000
2500
3000
3500
0 200 400 600 800 1000 1200 1400 1600
UCC.N
4000
4500
5000
UCC.E
For higher values
contact ABB
Rated through-current (A)
Step
voltage
(V)
500
0
1000
1500
2000
2500
3000
3500
0 200 400 600 800 1000 1200 1400 1600
UCD.N
4000
4500
5000
UCD.E
UCD.N
UCD.E
For higher values
contact ABB
Fig. 15. Rated phase step voltage for type UCL.
Fig. 17. Rated phase step voltage for type UCD.
Fig. 16. Rated phase step voltage for type UCC.
26. 26 1ZSE 5492-105 en, Rev. 8
Rated through-current (A)
No.of
operations
50000
0
100000
150000
200000
250000
300000
350000
400000
450000
500000
0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500
UCG.N,B
100% load
80% average load
80% average load
UCG.E,T
100% load
Rated through-current (A)
No.of
operations
100000
0
200000
300000
400000
500000
600000
700000
800000
900000
1000 000
0 100 200 300 600 800 900 1000 1100
VUCG.N,B
400 500 700 1200 1300 1400 1500 1600 1700
VUCG.E,T
Coarse fine regulation leakage inductance switching
When operating from the ends of the fine or the coarse winding a high
leakage inductande might appear causing a phase shift between the
switched current and the recovery voltage. This value has to be given
when ordering an OLTC so a proper dimensioning is possible.
The leakage inductance value can be given in our order data sheet
or be calculated by us from active part dimensions and number of
turns. For more information, see IEC 60214-2 or product information
1ZSC000498-ABB.
Contact life
The predicted contact life of the fixed and moving contact of the diverter
switch, is shown as a function of the rated through current in the dia-
grams below. It is based on the type test with 50000 switching operations,
and a current corresponding to the maximum rated through current. The
contact life is stated on the rating plate.
Fig. 18. Contact life for type UCG.
Fig. 19. Contact life for type VUCG.
28. 28 1ZSE 5492-105 en, Rev. 8
Standards and testing
The on-load tap-changers made by ABB fulfil the requirements according
to IEC 60214-1, 2003-02, and IEEE C57.131-1995.
The type tests include:
■
■ Contact temperature rise test
■
■ Switching tests
■
■ Short-circuit current test
■
■ Transition impedance test
■
■ Mechanical tests
■
■ Dielectric tests
The routine tests include:
■
■ Check of assembly
■
■ Mechanical test
■
■ Sequence test
■
■ Auxiliary circuits insulation test
■
■ Vacuum test
■
■ Final inspection
Rating plate
Insulation levels
LI is the lightning impulse (1.2/50 µs) to earth. pf is the power frequency
test voltage to earth (60 s). The insulation levels are indicated as impulse
withstand voltage – power frequency withstand voltage.
The tests were carried out according to IEC 60214-1, 2003-02, with a
new on-load tap-changer and clean insulation transformer oil I -30 °C ac-
cording to IEC 60296. The withstand voltage value of the oil was higher
than 40 kV/2.5 mm (IEC 60156).
Fig. 23. Example of rating plate
fm_00299
29. 29
1ZSE 5492-105 en, Rev. 8
a2
a1
b1
b2
e1
g1
b1
a2 a1
b1
b2
e1
g1
b1
Fig. 24. Linear switching.
corresponding
contact in
adjacent
phase
Linear
L
Insulation levels to earth (g1)
For UCG 380–150 kV, 650–275 kV, 750–325 kV and
1050–460 kV
For UCL 380–150 kV, 650–275 kV, 750–325 kV and
1050–460 kV
For UCC and UCD 380–150 kV, 650–275 kV and 1050–460 kV
Lightning impulse levels (LI) and power frequency levels (Pf) corresponds
to the following Um
-values acc. to IEC:
LI (kV) Pf (kV) Um (kV)
380 150 72,5
650 275 145
750 325 170
1050 460 300
Fig. 25. Reversing switching.
corresponding
contacts in
adjacent phase
Reversing
R
30. 30 1ZSE 5492-105 en, Rev. 8
a2 a1 f1
d1
b2
e1
g1
b1
c1
f2
d1
a1 Between electrically adjacent contacts in the tap selector, not
connected.
a2 Between the ends of the fine regulating winding (across range). For
coarse/fine switching in minus position, this means between the
freely oscillating end of the coarse winding and any end of the fine
winding.
b1 Between not connected taps of different phases in the fine selector
b2 Between open contacts of different phases in the diverter switch.
c1 Between ends of the coarse winding in coarse/fine switching
d1 Between not connected taps of different phases in the coarse selec-
tor (coarse/fine switching)
e1 Between preselected tap and connected tap of one phase in the di-
verter switch and in the tap selector.
f1 Between any end of the coarse winding and connected tap
f2 Between any end of the coarse winding and the middle of the fine
winding.
g1 Connected tap to earth
Fig. 26. Coarse/Fine switching.
corresponding
contacts in
adjacent phase
Coarse/Fine
D
31. 31
1ZSE 5492-105 en, Rev. 8
Withstand voltages
UCG and VUCG with tap selector C
All values given as 1.2/50 µs impulse withstand voltage (kV) – power frequency withstand voltage (kV).
a1 is not valid since the contact locations are such that electrically adjacent contacts are never
physically adjacent, see connection diagrams in this document.
Within one phase Between phases for neutral point
a1 a2 c1 f1 f2 e1 b2 b1 d1
- 350-140 400-150 400-150 400-150 100-20 100-20 400-150 400-150
UCG and VUCG with tap selector I
All values given as 1.2/50 µs impulse withstand voltage (kV) – power frequency withstand voltage (kV).
a1 is not given since the contact locations are such that electrically adjacent contacts are never
physically adjacent, see connection diagrams in this document.
Type of
switching
No. of
positions
Within one phase Between phases for neutral
point
a2 c1 f1 f2 e1 b2 b1 d1
L -14 300-125 - - - 100-20 100-20 300-125 -
L 15-16 290-120 - - - 100-20 100-20 300-125 -
L 17-18 250-95 - - - 100-20 100-20 300-125 -
R -13 300-125 - - - 100-20 100-20 300-125 -
R 14-15 250-95 - - - 100-20 100-20 300-125 -
R 16-27 300-125 - - - 100-20 100-20 300-125 -
R 28-31 290-120 - - - 100-20 100-20 300-125 -
R 32-35 250-95 - - - 100-20 100-20 300-125 -
D -13 300-125 350-140 350-140 350-140 100-20 100-20 300-125 350-140
D 14-15 250-95 350-140 350-140 350-140 100-20 100-20 300-125 350-140
D 16-27 300-125 350-140 350-140 350-140 100-20 100-20 300-125 350-140
D 28-31 290-120 350-140 350-140 350-140 100-20 100-20 300-125 350-140
D 32-35 250-95 350-140 350-140 350-140 100-20 100-20 300-125 350-140
32. 32 1ZSE 5492-105 en, Rev. 8
UCG and VUCG with tap selector III unshielded version
All values given as 1.2/50 µs impulse withstand voltage (kV) – power frequency withstand voltage (kV).
Type of
switching
No. of
positions
Within one phase Between phases for neutral
point
a1 a2 c1 f1 f2 e1 b2 b1 d1
L -14 300-125 490-150 - - - 100-20 100-20 500-160 -
L 15-16 300-125 420-150 - - - 100-20 100-20 500-160 -
L 17-18 300-125 350-140 - - - 100-20 100-20 500-160 -
R -11 300-125 490-150 - - - 100-20 100-20 500-160 -
R 12-13 300-125 420-150 - - - 100-20 100-20 500-160 -
R 14-15 300-125 350-140 - - - 100-20 100-20 500-160
R 16-27 300-125 490-160 - - - 100-20 100-20 500-160 -
R 28-31 300-125 420-150 - - - 100-20 100-20 500-160 -
R 32-35 300-125 350-140 - - - 100-20 100-20 500-160 -
D -11 300-125 490-160 600-200 600-200 600-200 100-20 100-20 500-160 600-200
D 12-13 300-125 420-150 600-200 600-200 600-200 100-20 100-20 500-160 600-200
D 14-15 300-125 350-140 600-200 600-200 600-200 100-20 100-20 500-160 600-200
D 16-27 300-125 490-160 600-200 600-200 600-200 100-20 100-20 500-160 600-200
D 28-31 300-125 420-150 600-200 600-200 600-200 100-20 100-20 500-160 600-200
D 32-35 300-125 350-140 600-200 600-200 600-200 100-20 100-20 500-160 600-200
UCG and VUCG with tap selector III shielded version
All values given as 1.2/50 µs impulse withstand voltage (kV) – power frequency withstand voltage (kV).
Type of
switching
No. of
positions
Within one phase Between phases for neutral
point
a1 a2 c1 f1 f2 e1 b2 b1 d1
L -14 300-125 550-180 - - - 100-20 100-20 550-180 -
L 15-16 300-125 480-160 - - - 100-20 100-20 550-180 -
L 17-18 300-125 400-150 - - - 100-20 100-20 550-180 -
L 19-22 300-125 350-125 - - - 100-20 100-20 550-180 -
R -11 300-125 550-180 - - - 100-20 100-20 550-180 -
R 12-13 300-125 480-160 - - - 100-20 100-20 550-180 -
R 14-15 300-125 400-150 - - - 100-20 100-20 550-180 -
R 16-27 300-125 550-180 - - - 100-20 100-20 550-180 -
R 28-31 300-125 480-160 - - - 100-20 100-20 550-180 -
R 32-35 300-125 400-150 - - - 100-20 100-20 550-180 -
D -11 300-125 550-180 600-200 600-200 600-200 100-20 100-20 550-180 600-200
D 12-13 300-125 480-160 600-200 600-200 600-200 100-20 100-20 550-180 600-200
D 14-15 300-125 400-150 600-200 600-200 600-200 100-20 100-20 550-180 600-200
D 16-27 300-125 550-180 600-200 600-200 600-200 100-20 100-20 550-180 600-200
D 28-31 300-125 480-160 600-200 600-200 600-200 100-20 100-20 550-180 600-200
D 32-35 300-125 400-150 600-200 600-200 600-200 100-20 100-20 550-180 600-200
33. 33
1ZSE 5492-105 en, Rev. 8
UCL with tap selector III unshielded version
All values given as 1.2/50 µs impulse withstand voltage (kV) – power frequency withstand voltage
(kV).
Type of
switching
No. of
positions
Within one phase Between phases for neutral
point
a1 a2 c1 f1 f2 e1 b2 b1 d1
L -14 300-125 490-150 - - - 130-20 130-20 500-160 -
L 15-16 300-125 420-150 - - - 130-20 130-20 500-160 -
L 17-18 300-125 350-140 - - - 130-20 130-20 500-160 -
R -11 300-125 490-150 - - - 130-20 130-20 500-160 -
R 12-13 300-125 420-150 - - - 130-20 130-20 500-160 -
R 14-15 300-125 350-140 - - - 130-20 130-20 500-160 -
R 16-27 300-125 490-160 - - - 130-20 130-20 500-160 -
R 28-31 300-125 420-150 - - - 130-20 130-20 500-160 -
R 32-35 300-125 350-140 - - - 130-20 130-20 500-160 -
D -11 300-125 490-160 600-200 600-200 600-200 130-20 130-20 500-160 600-200
D 12-13 300-125 420-150 600-200 600-200 600-200 130-20 130-20 500-160 600-200
D 14-15 300-125 350-140 600-200 600-200 600-200 130-20 130-20 500-160 600-200
D 16-27 300-125 490-160 600-200 600-200 600-200 130-20 130-20 500-160 600-200
D 28-31 300-125 420-150 600-200 600-200 600-200 130-20 130-20 500-160 600-200
D 32-35 300-125 350-140 600-200 600-200 600-200 130-20 130-20 500-160 600-200
UCL with tap selector III shielded version
All values given as 1.2/50 µs impulse withstand voltage (kV) – power frequency withstand voltage
(kV).
Type of
switching
No. of
positions
Within one phase Between phases for neutral
point
a1 a2 c1 f1 f2 e1 b2 b1 d1
L -14 300-125 550-180 - - - 130-20 130-20 550-180 -
L 15-16 300-125 480-160 - - - 130-20 130-20 550-180 -
L 17-18 300-125 400-150 - - - 130-20 130-20 550-180 -
L 19-22 300-125 350-125 - - - 130-20 130-20 550-180 -
R -11 300-125 550-180 - - - 130-20 130-20 550-180 -
R 12-13 300-125 480-160 - - - 130-20 130-20 550-180 -
R 14-15 300-125 400-150 - - - 130-20 130-20 550-180 -
R 16-27 300-125 550-180 - - - 130-20 130-20 550-180 -
R 28-31 300-125 480-160 - - - 130-20 130-20 550-180 -
R 32-35 300-125 400-150 - - - 130-20 130-20 550-180 -
D -11 300-125 550-180 600-200 600-200 600-200 130-20 130-20 550-180 600-200
D 12-13 300-125 480-160 600-200 600-200 600-200 130-20 130-20 550-180 600-200
D 14-15 300-125 400-150 600-200 600-200 600-200 130-20 130-20 550-180 600-200
D 16-27 300-125 550-180 600-200 600-200 600-200 130-20 130-20 550-180 600-200
D 28-31 300-125 480-160 600-200 600-200 600-200 130-20 130-20 550-180 600-200
D 32-35 300-125 400-150 600-200 600-200 600-200 130-20 130-20 550-180 600-200
34. 34 1ZSE 5492-105 en, Rev. 8
UCD with tap selector III unshielded version
All values given as 1.2/50 µs impulse withstand voltage (kV) – power frequency withstand voltage (kV).
Type of
switching
No. of
positions
Within one phase Between phases for neutral
point
a1 a2 c1 f1 f2 e1 b2 b1 d1
L -14 300-125 490-150 - - - 200-20 200-20 500-160 -
L 15-16 300-125 420-150 - - - 200-20 200-20 500-160 -
L 17-18 300-125 350-140 - - - 200-20 200-20 500-160 -
R -11 300-125 490-150 - - - 200-20 200-20 500-160 -
R 12-13 300-125 420-150 - - - 200-20 200-20 500-160 -
R 14-15 300-125 350-140 - - - 200-20 200-20 500-160 -
R 16-27 300-125 490-160 - - - 200-20 200-20 500-160 -
R 28-31 300-125 420-150 - - - 200-20 200-20 500-160 -
R 32-35 300-125 350-140 - - - 200-20 200-20 500-160 -
D -11 300-125 490-160 600-200 600-200 600-200 200-20 200-20 500-160 600-200
D 12-13 300-125 420-150 600-200 600-200 600-200 200-20 200-20 500-160 600-200
D 14-15 300-125 350-140 600-200 600-200 600-200 200-20 200-20 500-160 600-200
D 16-27 300-125 490-160 600-200 600-200 600-200 200-20 200-20 500-160 600-200
D 28-31 300-125 420-150 600-200 600-200 600-200 200-20 200-20 500-160 600-200
D 32-35 300-125 350-140 600-200 600-200 600-200 200-20 200-20 500-160 600-200
UCD with tap selector III shielded version
All values given as 1.2/50 µs impulse withstand voltage (kV) – power frequency withstand voltage (kV).
Type of
switching
No. of
positions
Within one phase Between phases for neutral
point
a1 a2 c1 f1 f2 e1 b2 b1 d1
L -14 300-125 550-180 - - - 200-20 200-20 550-180 -
L 15-16 300-125 480-160 - - - 200-20 200-20 550-180 -
L 17-18 300-125 400-150 - - - 200-20 200-20 550-180 -
L 19-22 300-125 350-125 - - - 200-20 200-20 550-180 -
R -11 300-125 550-180 - - - 200-20 200-20 550-180 -
R 12-13 300-125 480-160 - - - 200-20 200-20 550-180 -
R 14-15 300-125 400-150 - - - 200-20 200-20 550-180 -
R 16-27 300-125 550-180 - - - 200-20 200-20 550-180 -
R 28-31 300-125 480-160 - - - 200-20 200-20 550-180 -
R 32-35 300-125 400-150 - - - 200-20 200-20 550-180 -
D -11 300-125 550-180 600-200 600-200 600-200 200-20 200-20 550-180 600-200
D 12-13 300-125 480-160 600-200 600-200 600-200 200-20 200-20 550-180 600-200
D 14-15 300-125 400-150 600-200 600-200 600-200 200-20 200-20 550-180 600-200
D 16-27 300-125 550-180 600-200 600-200 600-200 200-20 200-20 550-180 600-200
D 28-31 300-125 480-160 600-200 600-200 600-200 200-20 200-20 550-180 600-200
D 32-35 300-125 400-150 600-200 600-200 600-200 200-20 200-20 550-180 600-200
35. 35
1ZSE 5492-105 en, Rev. 8
UCC with tap selector IV
All values given as 1.2/50 µs impulse withstand voltage (kV) – power frequency withstand voltage (kV).
Type of
switching
Shielded
(s)/
unshielded
(us)
No. of
positions
Within one phase Between phases for neutral
point
a1 a2 c1 f1 f2 e1 b2 b1 d1
L us -16 200-80 300-125 - - - 200-20 200-20 300-125 -
L s -16 200-80 500-170 - - - 200-20 200-20 500-170 -
L us 17-18 200-80 300-125 - - - 200-20 200-20 300-125 -
L s 17-18 200-80 450-150 - - - 200-20 200-20 500-170 -
R us -13 200-80 300-125 300-125 - - 200-20 200-20 300-125 -
R s -13 200-80 500-170 600-200 - - 200-20 200-20 500-170 -
R us 14-15 200-80 250-95 300-125 - - 200-20 200-20 300-125 -
R s 14-15 200-80 400-150 600-200 - - 200-20 200-20 500-170 -
R us 16-27 200-80 300-125 300-125 - - 200-20 200-20 300-125 -
R s 16-27 200-80 500-170 600-200 - - 200-20 200-20 500-170 -
R us 28-35 200-80 250-95 300-125 - - 200-20 200-20 300-125 -
R s 28-35 200-80 400-150 600-200 - - 200-20 200-20 500-170 -
D us 16-27 200-80 300-125 300-125 350-150 350-150 200-20 200-20 300-125 350-150
D s 16-27 200-80 500-170 600-200 600-200 600-200 200-20 200-20 500-170 600-200
D us 28-35 200-80 250-95 300-125 350-150 350-150 200-20 200-20 300-125 350-150
D s 28-35 200-80 400-150 600-200 600-200 600-200 200-20 200-20 500-170 600-200
36. 36 1ZSE 5492-105 en, Rev. 8
Short-circuit current strength
The short circuit current strength is verified with three applications of 2 or 3 seconds duration, with-
out moving the contacts between the three applications. Each application has an initial value of at
least 2.5 times the rms value.
Table 4.
Diverter
switch
Tap selector Max rated
through-
current,
A rms
Type of
connection
2 s duration,
kA rms
3 s duration,
kA rms
Peak value,
kA
UCG C 300, 400 N,B,E,T 6 6 15
C 600 N,B,E,T 6 6 15
C 500 E,T 6 6 15
C 600 E,T 6 6 15
C 700, 900 E,T 12 12 30
C 1050, 1200 E,T 12 12 30
C 1500 E,T 16 16 40
I 300 N,B,E,T 71)
61)
18
I 500 N,B,E,T 71)
61)
18
I 600 N,B,E,T 71)
61)
18
I 900 E,T 17 17 43
I 1200 E,T 17 17 43
I 1500 E,T 18 18 45
III 300 N,B,E,T 71)
61)
18
III 500 N,B,E,T 71)
61)
18
III 600 N,B,E,T 71)
61)
18
III 900 E,T 10 10 25
III 1200 E,T 17 17 43
III 1500 E,T 18 18 45
VUCG C 400 N,B,E,T 6 6 15
C 600 N,B,E,T 6 6 15
C 800 E,T 12 12 30
I 600 N,B,E,T 81)
81)
22
I 1200 E,T 15 15 38
I 1500 E,T 16 16 43
III 700 N,B,E,T 81)
81)
22
III 1600 E,T 16 16 43
UCL III 600 N,B,E,T 111)
111)
30
III 900 N,B,E,T 111)
111)
30
III 1800 E,T 24 24 64
III 2400 E,T 28 27 79
UCD III 1000 N,B,E,T 18 182)
45
III 1600 E,T 18 182)
45
UCC IV 1600 N,E 18 182)
45
1)
In case of UC..E,T or VUC..E,T higher values are possible on request.
2)
Available for reinforced performance with 24 kArms
and 60 kApeak
.
37. 37
1ZSE 5492-105 en, Rev. 8
Highest phase service voltage across the regulating winding
The table below show the highest permissible phase service voltage for
the different types of connections.
Table 5. Highest permissible phase service voltage across the regulating
winding.
Across the regulating
winding (kV)
Across the coarse and fine
winding (kV)
Contact shieldings: with without with without
Tap-changer,
tap selector
UCC.N IV 52 35 75 45
UCD.N III
UCL.N III
UCG.N III
UCC.E IV 68 45 80 60
UCD.E, III
UCL.T, E, B III
UCG.T, E, B III
UCG.N C, I - 35 - 40
UCG.T, E, B C, I - 35 - 45
VUCG.T, E, B III 68 45 80 60
VUCG.N C, I - 35 - 40
VUCG.T, E, B C, I - 35 - 45
Rated through-current
The rated through-current of the on-load tap-changer is the current which
the on-load tap-changer is capable of transferring from one tapping to the
other at the relevant rated step voltage, and which can be carried continu-
ously whilst meeting the technical data in this document. The rated through
current is normally the same as the highest tapping current. The rated
through-current is limited by the step voltage according to the curves in the
diagrams, Figs. 13 - 17. The rated through-current determines the dimen-
sioning of the transition resistors and the contact life. The rated through-
current is stated on the rating plate, Fig. 23.
Occasional overloading
If the rated through-current of the tap-changer is not less than the high-
est value of tapping current of the tapped winding of the transformer, the
tap-changer will not restrict the occasional overloading of the transformer,
according to IEC 60076-7, 2005-12, and ANSI/IEEE C57-91-1995.
To meet these requirements, the UC models have been designed so that
the contact temperature rise over the surrounding oil does not exceed
20 K when loaded with a current of 1.2 times the maximum rated through
current of the tap-changer.
The contact life stated on the rating plate is given with consideration that
currents of maximum 1.5 times the rated through current occur during a
maximum of 3 % of the tap-change operations. Overloading beyond these
values, results in increased contact wear and shorter contact life.
For more information about overloading, read the appropriate parts of
IEC 60214-2, 2004-10.
38. 38 1ZSE 5492-105 en, Rev. 8
Oil temperature
Provided that insulating oil of class “Transformer oil -30 °C” according to
IEC 60296, 2003-11, is used, the temperature of the oil surrounding the
on-load tap-changer shall be between -25 and +105 °C for normal opera-
tion, as illustrated below. The range for UC (not VUC!) can be extended to
-40 °C provided that the viscosity does not exceed 2500 mm2
/s (=cst).
Individual brands need to be evaluated from case to case because of dif-
ferences in viscosity compared to transformer grade mineral oil and the
subsequent difference in heat dissipation. Also dielectric strengths and
influence form moisture needs to be considered. Switching in vacuum
generally opens for use of a wider range of insulating fluids.
1) No operations allowed.
2) Emergency overloading. The on-load tap-changer will not restrict the
occasional overloading of the transformer according to the standards
stated in section Occasional overloading.
3) Normal operating range.
4) UC: When operating within this range, no overloading is allowed.
VUC: No operation allowed.
5) UC: Operation with de-energized transformer only.
VUC: No operation allowed.
39. 39
1ZSE 5492-105 en, Rev. 8
Coarse/fine regulation leakage inductance switching
When changing from the end of the fine winding to the end of the coarse
winding, a high leakage inductance can be set up with the two wind-
ings in series. The critical moment occurs at switching the tap-changers
mechanical mid-position, as the circulating current is passing through not
only one loop but also the entire coarse and fine tap winding.
The leakage inductance that occurs from one loop, Fig. 28, is neglectible
but can be substantial from the complete coarse and fine winding, Fig. 29.
This leakage inductance causes a phase shift between switching current
and recovery voltage that makes the breaking more severe. The OLTC
must be dimensioned accordingly. The leakage inductance shall be speci-
fied in the ordering data sheet.
For certain winding configurations, such as coarse and fine windings lo-
cated axially, this value might be that high that it requires a larger OLTC
than would be needed otherwise. For more information, see product in-
formation 1ZSC000498-ABB as well as IEC 60214-2, 2004-10, or consult
the supplier for advice.
Main winding
Coarse winding
Fine winding
Fig. 28. Normal operation Fig. 29. Operation with high leakage inductance.
40. 40 1ZSE 5492-105 en, Rev. 8
Tie-in resistor and tie-in resistor switch
When the change-over selector operates, the tapped winding is discon-
nected for a short time. The voltage of that winding is then determined by
the voltage of and the capacitances to the surrounding windings or tank
wall/core. For certain winding layouts, voltages and capacitances, the
capacitive controlled voltage will reach magnitudes that are too high for
the change-over selector. In these cases potential controlling resistors, so
called tie-in resistors, should be connected according to Fig. 30.
The tie-in resistor is connected between the middle of the tapped wind-
ing and the connection point on the bottom of the diverter switch housing,
see single phase diagrams in this document. This means that power is
continuously dissipated in the resistors that add to the no-load losses of
the transformers. The resistors must also be dimensioned for the power
dissipation.
The tie-in resistors are normally mounted separate from the OLTC but
can be mounted under the tap selector provided that tie-in resistor switch
is not used. Please contact the supplier for advice in such case!
The following limits apply to the change-over selectors of the different tap
selectors:
Tap selector Max recovery voltage (kV rms) Max capacitive current (mA rms)
C 35 200
I 35 200
III 35 300
IV 35 300
The capacitive current is the current going through the change-over se-
lector before it opens.
Diverter switch
Tie-in resistor
switch
Tie-in resistor
Tap selector
Main winding
Regulating winding
wIth change-over
selector
Fig. 30. Tie-in resistor example.
41. 41
1ZSE 5492-105 en, Rev. 8
HV
C1
RW
C2
+ -
U
In the figure above is a switch, the tie-in resistor switch, that connects
the tie-in resistors only when they are needed. The switch is a part of the
tap selector and is mounted on the bottom plate of the tap selector, see
dimension drawings in this document.
This switch is used when the no-load losses must be kept low or/and
when the continuous power in the tie-in resistors is too high. The tie-in
resistor switch is available for all tap selectors except tap selector C.
When ordering, give the winding layout and information according to the
example below and the supplier will calculate whether tie-in resistors are
needed or not. If needed, the supplier will choose the correct tie-in resis-
tors. If a tie-in resistor switch is needed for limiting the no-load losses,
give that information in the ordering data sheet! If anything is unclear,
contact the manufacturer.
Example
C1 = Capacitance between HV and RW
C2 = Capacitance between tank and RW
Frequency 50 Hz
Winding Phase voltage Connection
High voltage (HV) 132 kV (H1) Delta
Regulating winding (RW)
(Voltage across)
13.3 kV (U) Plus/Minus
Tank
42. 42 1ZSE 5492-105 en, Rev. 8
Installation and maintenance
On-load tap-changer
Installation
The on-load tap-changers can be delivered for cover-mounting method or
yoke-mounting method onto the transformer.
For detailed installation instructions, consult the appropriate Installation
and Commissioning Guide.
Drying
The on-load tap-changer must be stored indoors and left in its plastic
shipping cover until time for assembly. The OLTC should be subjected to
drying before taken into service. The diverter switch should not partici-
pate in the drying process. For further instructions refer to the Installation
Guide.
Weights
The tables below shows all the weights of the UC range of tap-changers.
Table 7. Weights for type UCG.
On-load tap-changer
type designation
Approximate weight in kg
Tap-changer
without oil1)
Required oil Total
UCG.N 380-750/300-600 425 185 610
1050/300-600 435 230 665
UCG.T 380-750/300-900 1025 3x185 1580
380-750/1050-1500 1190 3x185 1745
1050/300-900 1090 3x230 1780
1050/1050-1500 1225 3x230 1915
UCG.B 380-750/300-600 760 2x185 1130
1050/300-600 780 2x230 1240
UCG.E 380-750/300-900 360 185 545
380-750/1050-1500 410 185 595
1050/300-900 370 230 600
1050/1050-1500 425 230 655
1)
The weight of the diverter switch, approximately 90 kg, is included.
44. 44 1ZSE 5492-105 en, Rev. 8
Table 10. Weights for type UCD.
On-load tap-changer
type designation
Approximate weight in kg
Tap-changer
without oil1)
Required oil Total
UCD.N 380/1000 900 700 1600
650/1000 940 760 1700
1050/1000 960 860 1820
UCD.E 380/1000 840 700 1540
380/1800 870 700 1570
380/2400 900 700 1600
650/1000 880 760 1640
650/1800 910 760 1670
650/2400 940 760 1700
1050/1000 900 860 1760
1050/1800 930 860 1790
1050/2400 960 860 1820
1)
The weight of the diverter switch, approximately 250 kg, is included.
Table 11. Weights for type UCC.
On-load tap-changer
type designation
Approximate weight in kg
Tap-changer
without oil1)
Required oil Total
UCC.N 380/1600 1140 700 1840
650/1600 1180 760 1940
1050/1600 1200 860 2060
UCC.E 380/1600 1040 700 1740
650/1600 1080 760 1840
1050/1600 1100 860 1960
)
The weight of the diverter switch, approximately 250 kg, is included.
Oil filling
For details of oil filling, consult the appropriate Installation and
Commissioning Guide.
45. 45
1ZSE 5492-105 en, Rev. 8
Maintenance
For information about maintenance, the appropriate Maintenance Guide
should be used.
Pressure
During drying, the on-load tap-changers should have no pressure dif-
ference to the transformer. This is obtained by opening the VP-valve
in the bottom, see the Installation and commissioning guide for further
information.
During oil filling and testing, up to 200 kPa pressure difference to the at-
mosphere is allowed. During service, max. 150 kPa pressure difference to
the atmosphere is allowed.
The pressure difference to the transformer tank during oil filling and test-
ing is allowed to be max 100 kPa. During service, the pressure is recom-
mended to be as low as possible and not more than 50 kPa and then
preferably higher in the transformer tank. For higher pressures, contact
the supplier.
Accessories and protection devices
The tap-changer can be equipped with various protection devices. The
standard protection device is the pressure relay. An oil flow relay is also
available.
Pressure relief device with alarm signal is also available as well as some
other supervisory sensors.
For more information about accessories and protection devices see tech-
nical description 1ZSC000562-AAD.
46. 46 1ZSE 5492-105 en, Rev. 8
Motor-drive mechanism
Design
For detailed design description, see separate Technical Guides for Motor-
Drive Mechanisms types BUL or BUE, respectively.
Installation
The motor-drive mechanism is fitted to the outside of the transformer
tank, and connected to the on-load tap-changer by drive shafts and bevel
gears.
For the correct installation procedure, consult the appropriate Installation
Guide.
Maintenance
The motor-drive mechanism should be visually inspected anually.
For the correct inspection and maintenance procedures, consult the ap-
propriate Maintenance Guide.
Operating shafts
Length L1 (mm) L2 (mm) L3 and L4 (mm) Motor-drive
mechanism
Min/max 500/3100 525/3100 900/2700 BUE
500/3100 600/3100 – BUL
The minimum and maximum lengths refer to mechanical design only. For
L2 vertical shaft see following pages. Other shaft arrangements are avail-
able on request.
For standard shaft arrangements, the maximum angle (totally in two di-
rections) is 4°. For larger angles, special couplings are needed.
47. 47
1ZSE 5492-105 en, Rev. 8
Fig. A
L1
UCG.N, E
VUCG.N, E
UCL.N, E
UCD.N, E
UCC.N, E
Fig. B
L1
Fig. C
L3 L1
UCG.B
VUCG.B
UCL.B
Fig. D
L1 L3
Fig. E
L4 L3 L1
UCG.T
VUCG.T
UCL.T
Fig. F
L1 L3 L4
Fig. 31. Positioning of motor-drive mechanism.
For singel units
(UC..E, N and
VUC..E, N) the
gear box of the
tap-changer might
be mounted in the
angle given below.
48. 48 1ZSE 5492-105 en, Rev. 8
Dimensions
Type UCG/C and VUCG/C
Dimensions in mm. The design, technical data and dimensions are sub-
ject to alteration without notice. For more information, see the dimension
drawings.
C/L Tap selector C/L Diverter switch
Section A – A
Plus/Minus and
Coarse/Fine
switching
Section A – A
Linear switching
145
353
80
230
134
440
R210
570
570
615
D=420
615
R210
818
194
36
75
157
L2
2907)
L1
H32)
A A
205
D=600
D=470
345
390
30
H2
70
4057)
1)
1)
D=420
332
D=740
111
16O
H1
BUL
BUL
BUE2
BUE2
49. 49
1ZSE 5492-105 en, Rev. 8
Type UCG/I and VUCG/I
Dimensions in mm. The design, technical data and dimensions are sub-
ject to alteration without notice.
C/L Tap selector C/L Diverter switch
Section A – A
Plus/Minus and
Coarse/Fine
switching
Section A – A
Linear switching
36
1)
610
194
75
157
L2
L1
H1
H2
D=600
D=470
1)
1)
30
6053)
665
3903)
500
500 4103)
4203)
530
332
3397)
390
145
353
818
230
16°
80
440
4)
70
30
195
H32)
205
D=740
134
A
A
111
4057)
BUL
BUL
BUE2
BUE2
50. 50 1ZSE 5492-105 en, Rev. 8
Type UCG/III and VUCG/III
Dimensions in mm. The design, technical data and dimensions are sub-
ject to alteration without notice.
Model for mounting on
transformer’s active part
Model for cover mounting
C/L Diverter switch
C/L Tap selector
Section B - B
Linear switching
Section B - B
Plus/Minus and
Coarse/Fine switching
H2
H1
B
B
85
H1+106
30
385
586
4903)
8403)
293
936
4903)
4903)
580
2453)
580
4)
51. 51
1ZSE 5492-105 en, Rev. 8
Tables UCG and VUCG
Diverter switch housing
For tap
selector size
Impulse withstand
voltage to earth (kV)
H1
(mm)
H1, short
version (mm)
H3 2
)
(mm)
H3 2
), short
version (mm)
C 380, 650, 750 1192 972 1400 1200
1050 1492 1272 1700 1500
I 380, 650, 750 1317 1097 1400 1200
1050 1617 1397 1700 1500
III 380, 650, 750 1354 1134 1400 1200
1050 1654 1434 1700 1500
Tap selector
For on-load tap-
changer type
Max rated
through-current
(A)
H2, size C (mm) H2, size I (mm) H2, size III (mm)
UCG.N, VUCG.N 400 959 - -
300-600 - 1026 1160
UCG.E, UCG.T 5)
,
VUCG.E, VUCG.T 5)
400 519 - -
300-600 - 526 552
700 739 - -
900 - - 552
1050 959 - -
1200 - 756 856
1500 - 1026 856
UCG.B 6)
, VUCG.B 6)
400 Single-phase unit 519
Two-phase unit 739
- -
300-600 - Single-phase unit 526
Two-phase unit 776
Single-phase unit 552
Two-phase unit 856
1)
Shielding rings are used only for insulation level 650-275 kV and higher.
2)
Space required for lifting the diverter switch, excluding the lifting equipment.
3)
Dimension without shielding ring.
4)
For tie-in resistor switch add 360 mm.
5)
UCG.T and VUCG.T consists of three single-phase units.
6)
UCG.B and VUCG.B consists of one single-phase and one two-phase unit arranged as shown in the dimension drawing
for UCL.B.
7)
Space required for protective equipment.
52. 52 1ZSE 5492-105 en, Rev. 8
Type UCL/III
Dimensions in mm. The design, technical data and dimensions are sub-
ject to alteration without notice.
Type UCL.N (three-phase, star point) and
type UCL.E (single-phase)
Section A – A
Plus/Minus and
Coarse/Fine
switching
Section A – A
Linear switching
3018)
4808)
53. 53
1ZSE 5492-105 en, Rev. 8
Design for premounting
on the active part of the
transformer
Type UCL.B (three-phase, delta)
4)
4)
54. 54 1ZSE 5492-105 en, Rev. 8
Tables UCL
Diverter switch housing
Impulse withstand voltage to earth (kV) H1 (mm) H3 2
) (mm)
380 1415 1500
650 1615 1700
1050 1815 1900
For mounting on active part 5)
H1+85 H3+100
Tap selector
For on-load tap-changer type Max rated through-current (A) H2, size III (mm)
UCL.N 600-900 1160
UCL.E, UCL.T 6)
600-900 552
1800 856
2400 1160
UCL.B 7)
600-900 Single-phase unit H22 = 552
Two-phase unit H21 = 856
1)
Shielding rings are used only for insulation level 650-275 kV and higher.
2)
Space required for lifting the diverter switch, excluding the lifting equipment.
3)
Dimension without shielding-ring.
4)
For tie-in resistor switch add 370 mm.
5)
Model for mounting on transformers active part.
6)
UCL.T consists of three single-phase units.
7)
UCL.B consists of one single-phase unit and one two-phase unit.
8)
Space required for protective equipment.
55. 55
1ZSE 5492-105 en, Rev. 8
Type UCD/III
Dimensions in mm. The design, technical data and dimensions are sub-
ject to alteration without notice.
2046)
7886)
56. 56 1ZSE 5492-105 en, Rev. 8
Tables UCD
Diverter switch housing
Impulse withstand voltage to earth (kV) H1 (mm) H3 2
) (mm)
380 1594 1700
650 1734 1900
1050 1934 2200
Tap selector
For on-load tap-changer type Max rated through-current (A) H2, size III (mm)
UCD.N 1000 1160
UCD.E 1000 552
1800 856
2400 1160
1)
Shielding rings are used only for insulation level 650-275 kV and higher.
2)
Space required for lifting the diverter switch, excluding the lifting equipment.
3)
Dimension without shielding ring.
4)
For tie-in resistor switch add 370 mm.
5)
When two or three units are fitted together (three-phase delta and three-phase fully insulated respectively) the distance
between the units (c) must be at least 1340 mm from mechanical point of view. For final dimensioning, check the
insulation distance required.
6)
Space required for protective equipment.
57. 57
1ZSE 5492-105 en, Rev. 8
Type UCC/IV
Dimensions in mm. The design, technical data and dimensions are sub-
ject to alteration without notice.
58. 58 1ZSE 5492-105 en, Rev. 8
Tables UCC
Diverter switch housing
Impulse withstand voltage to earth (kV) H1 (mm) H3 2
) (mm)
380 1540 1700
650 1680 1900
1050 1880 2200
Tap selector
For on-load tap-changer type Max rated through-current (A) H2, size III (mm)
UCC.N 1200 1282
1600 1522
UCC.E 1600 1282
1)
Shielding rings are used only for insulation level 650-275 kV and higher.
2)
Space required for lifting the diverter switch, excluding the lifting equipment.
3)
Dimension without shielding ring.
4)
For tie-in resistor switch add 340 mm.
5)
When two or three units are fitted together (three-phase delta and three-phase fully insulated respectively) the distance
between the units (c) must be at least 1340 mm from mechanical point of view. For final dimensioning, check the
insulation distance required.
59. 59
1ZSE 5492-105 en, Rev. 8
Oil conservator
The transformer manufacturer must provide a conservator for the tap-
changer. Consider the below as a guideline for the design.
1. The breathing device should prevent moisture from getting into
the tap-changer compartment and let gases from the arcings out.
2. The oil volume should be such that the oil level always is within
the range of the oil level indicator at all predictable temperatures.
3. X corresponds to a height giving a max permissible pressure dif-
ference between the tap-changer tank and the transformer tank of
50 kPa.
4. H corresponds to a height giving a max pressure difference be-
tween the tap-changer and the atmosphere of 150 kPa.
5. The oil level for the tap-changer should be equal or below the oil
level of the transformer. Temporary during service the value is al-
lowed to be negative.
6. Vacuum proof conservator if the tap-changer should be oil filled
under vacuum with the conservator mounted.
Note that separate oil conservators for the transformer and the tap-
changer (also for the vacuum tap-changer) are recommended. Both oil
and air side should be separated. For transformers with common con-
servator for both the transformer and the tap-changer a filter should be
mounted in the pipe from the tap-changer to the conservator.
60. 60 1ZSE 5492-105 en, Rev. 8
Appendices: Single-Phase Diagrams
The basic connection diagrams illustrate the different types of switching
and the appropriate connections to the transformer windings. The dia-
grams illustrate the connections with the maximum number of turns in the
transformer winding, with the tap-changer in position 1.
The tap-changer can also be connected in such a way that position 1
gives a minimum effective number of turns in the transformer winding with
the tap-changer in position 1.
Appendix 1: Single-phase diagrams for UCG/C
Linear Plus/Minus Coarse/Fine
4 steps
Number of loops:
4
Number of tap positions:
5
5 steps
Number of loops:
5
Number of tap positions:
6
61. 61
1ZSE 5492-105 en, Rev. 8
Linear Plus/Minus Coarse/Fine
6 steps
Number of loops:
6
Number of tap positions:
7
7 steps
Number of loops:
7
Number of tap positions:
8
8 steps
Number of loops:
8 4 4 + 4
Number of tap positions:
9 9 9
62. 62 1ZSE 5492-105 en, Rev. 8
Linear Plus/Minus Coarse/Fine
10 steps
Number of loops:
10 5 5 + 5
Number of tap positions:
11 11 11
12 steps
Number of loops:
12 6 6 + 6
Number of tap positions:
13 13 13
13 steps
Number of loops:
13
Number of tap positions:
14
63. 63
1ZSE 5492-105 en, Rev. 8
Linear Plus/Minus Coarse/Fine
16 steps
Number of loops:
8 8 + 8
Number of tap positions:
17 17
18 steps
Number of loops:
10 9 + 10
Number of tap positions:
19 19
20 steps
Number of loops:
10 10 + 10
Number of tap positions:
21 21
64. 64 1ZSE 5492-105 en, Rev. 8
Linear Plus/Minus Coarse/Fine
22 steps
Number of loops:
12 11 + 12
Number of tap positions:
23 23
24 steps
Number of loops:
12 12 + 12
Number of tap positions:
25 25
26 steps
Number of loops:
14 13 + 14
Number of tap positions:
27 27
65. 65
1ZSE 5492-105 en, Rev. 8
Appendix 2: Single-phase diagrams for UCG/I
Linear Plus/Minus Coarse/Fine
4 steps
Number of loops:
4
Number of tap positions:
5
5 steps
Number of loops:
5
Number of tap positions:
6
6 steps
Number of loops:
6
Number of tap positions:
7
66. 66 1ZSE 5492-105 en, Rev. 8
Linear Plus/Minus Coarse/Fine
7 steps
Number of loops:
7
Number of tap positions:
8
8 steps
Number of loops:
8 4 4 + 4
Number of tap positions:
9 9 9
10 steps
Number of loops:
10 5 5 + 5
Number of tap positions:
11 11 11
67. 67
1ZSE 5492-105 en, Rev. 8
Linear Plus/Minus Coarse/Fine
12 steps
Number of loops:
12 6 6 + 6
Number of tap positions:
13 13 13
14 steps
Number of loops:
14 7 7 + 7
Number of tap positions:
15 15 15
16 steps
Number of loops:
16 8 8 + 8
Number of tap positions:
17 17 17
68. 68 1ZSE 5492-105 en, Rev. 8
Linear Plus/Minus Coarse/Fine
17 steps
Number of loops:
17
Number of tap positions:
18
18 steps
Number of loops:
10 9 + 10
Number of tap positions:
19 19
20 steps
Number of loops:
10 10 + 10
Number of tap positions:
21 21
69. 69
1ZSE 5492-105 en, Rev. 8
Linear Plus/Minus Coarse/Fine
22 steps
Number of loops:
12 11 + 12
Number of tap positions:
23 23
24 steps
Number of loops:
12 12 + 12
Number of tap positions:
25 25
26 steps
Number of loops:
14 13 + 14
Number of tap positions:
27 27
70. 70 1ZSE 5492-105 en, Rev. 8
Linear Plus/Minus Coarse/Fine
28 steps
Number of loops:
14 14 + 14
Number of tap positions:
29 29
30 steps
Number of loops:
16 15 + 16
Number of tap positions:
31 31
32 steps
Number of loops:
16 16 + 16
Number of tap positions:
33 33
71. 71
1ZSE 5492-105 en, Rev. 8
Linear Plus/Minus Coarse/Fine
34 steps
Number of loops:
18 17 + 18
Number of tap positions:
35 35
72. 72 1ZSE 5492-105 en, Rev. 8
Appendix 3: Single-phase diagrams for UCG/III, VUCG/III, UCL/III and
UCD/III
Linear Plus/Minus Coarse/Fine
4 steps
Number of loops:
4
Number of tap positions:
5
5 steps
Number of loops:
5
Number of tap positions:
6
6 steps
Number of loops:
6
Number of tap positions:
7
73. 73
1ZSE 5492-105 en, Rev. 8
Linear Plus/Minus Coarse/Fine
7 steps
Number of loops:
7
Number of tap positions:
8
8 steps
Number of loops:
8 4 4 + 4
Number of tap positions:
9 9 9
10 steps
Number of loops:
10 5 5 + 5
Number of tap positions:
11 11 11
74. 74 1ZSE 5492-105 en, Rev. 8
Linear Plus/Minus Coarse/Fine
12 steps
Number of loops:
12 6 6 + 6
Number of tap positions:
13 13 13
14 steps
Number of loops:
14 7 7 + 7
Number of tap positions:
15 15 15
16 steps
Number of loops:
16 8 8 + 8
Number of tap positions:
17 17 17
75. 75
1ZSE 5492-105 en, Rev. 8
Linear Plus/Minus Coarse/Fine
18 steps
Number of loops:
18 10 9 + 10
Number of tap positions:
19 19 19
20 steps
Number of loops:
20 10 10 + 10
Number of tap positions:
21 21 21
21 steps
Number of loops:
21
Number of tap positions:
22
76. 76 1ZSE 5492-105 en, Rev. 8
Linear Plus/Minus Coarse/Fine
22 steps
Number of loops:
12 11 + 12
Number of tap positions:
23 23
24 steps
Number of loops:
12 12 + 12
Number of tap positions:
25 25
26 steps
Number of loops:
14 13 + 14
Number of tap positions:
27 27
77. 77
1ZSE 5492-105 en, Rev. 8
Linear Plus/Minus Coarse/Fine
28 steps
Number of loops:
14 14 + 14
Number of tap positions:
29 29
30 steps
Number of loops:
16 15 + 16
Number of tap positions:
31 31
32 steps
Number of loops:
16 16 + 16
Number of tap positions:
33 33
78. 78 1ZSE 5492-105 en, Rev. 8
Linear Plus/Minus Coarse/Fine
34 steps
Number of loops:
18 17 + 18
Number of tap positions:
35 35
79. 79
1ZSE 5492-105 en, Rev. 8
Appendix 4: Single-phase diagrams for UCC/IV
Linear Plus/Minus Coarse/Fine
8 steps
Number of loops:
8 4
Number of tap positions:
9 9
10 steps
Number of loops:
10 5
Number of tap positions:
11 11
12 steps
Number of loops:
12 6
Number of tap positions:
13 13
80. 80 1ZSE 5492-105 en, Rev. 8
Linear Plus/Minus Coarse/Fine
14 steps
Number of loops:
14 7
Number of tap positions:
15 15
16 steps
Number of loops:
16 8 8 + 8
Number of tap positions:
17 17 17
17 steps
Number of loops:
17
Number of tap positions:
18
81. 81
1ZSE 5492-105 en, Rev. 8
Linear Plus/Minus Coarse/Fine
18 steps
Number of loops:
10 9 + 10
Number of tap positions:
19 19
20 steps
Number of loops:
10 10 + 10
Number of tap positions:
21 21
22 steps
Number of loops:
12 11 + 12
Number of tap positions:
23 23
82. 82 1ZSE 5492-105 en, Rev. 8
Linear Plus/Minus Coarse/Fine
24 steps
Number of loops:
12 12 + 12
Number of tap positions:
25 25
26 steps
Number of loops:
14 13 + 14
Number of tap positions:
27 27
28 steps
Number of loops:
14 14 + 14
Number of tap positions:
29 29
83. 83
1ZSE 5492-105 en, Rev. 8
Linear Plus/Minus Coarse/Fine
30 steps
Number of loops:
16 15 + 16
Number of tap positions:
31 31
32 steps
Number of loops:
16 16 + 16
Number of tap positions:
33 33
34 steps
Number of loops:
18 17 + 18
Number of tap positions:
35 35
