Catalogue

1ZBR 5499-101 (En)

Edition 8, 2012-50

De - energized Tap - Changer

Type LC

Technical Guide
Table of Contents Pages

* 1. General Information …………………………………..…………… 2

* 2. Design …………….………………………………………………..… 3

2.1 Standard Delivery of the tap-changer…………………….. 4

* 3. Electrical Data ………………………………………………...……. 5

* 4. Aplication ……………………………………………………………. 6

4.1 Standard configurations ………………………………….... 6

* 5. Dimensions …………………………………………………...…….. 9

5.1. Change-over units ……………………………………..…… 9

5.2. Operating Mechanism ………………………………….… 13
5.3. Mass Calculation ………………………………….………. 14

* 6. Recommendations for Positioning ……………………………. 16

6.1. Distances from contacts to earthed surfaces ……...… 16

6.2. Distances from the frame and drive shaft to the leads 16

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De - energized Tap - Changer Type LC

General information

Up to 650 kV impulse withstand voltage

500 A rated through current

 Vertical Assembling

 Short lenghts of tapping leads

 Compact and economical transformer design

 Hand drive mechanism on the tank wall at a suitable height

from ground level

 Easy installation

 Can be provided with interlocking switch and switch for

remote position indicator

 Up to 10 positions

2
Design

The Tap Changer provides a reliable method for adjusting of the voltage ratio in mineral oil
immersed transformers.
The Tap Changer is designed only for operations of de-energized transformers. The operating
mechanism and the position indicator is located externally, on the transformer tank wall.
The contact have a thermal suportability of 500 A , with temperature rise of only 10º C. This
low temperature rise is provided by a positive connection between stationary and moving
contacts. During the operation of the transformer, this temperature rise is assured by a positive
lock of the tap position.
The Tap Changer is designed to mount in a vertically position closed by the winding without
any cleats and leads assemblies of the tapping leads. Advantageous is the location of the Tap
Changer in the space between the outer windings of adjacent phases in order to have a very
compact and economic transformer design.
Each stationary contact is ready crimped to a flexible cable of 18.10 mm diameter, 150 mm²
cross-section and 1,04 mm single sided paper kraft crepe insulation. If you need a larger
quantity of kraft crepe paper or term stabilized paper insulation or nomex paper, it is not part of
our scope of supply.
According to current or voltage requirements the Tap Changer can be ordered with 1 or 2
contact-groups (Type LC1 or LC2), what means single or double bridging. The design of the
Tap Changer permits the location of each contact group in front of each tappings.
The mechanical connection of the Tap Changer is performed by the drive shaft. The drive shaft
can be ordered in fiberglass or steel according to the voltage requirements around the shaft
location.
The interface to the operating mechanism has a fiberglass shaft and universal joint
connections.
The operating mechanism is an external operating handle with a position indicator connected
to the operating shaft and numeral position indicator (1; 2; 3;... 10). Other indications for
example -5;... 1; 0; +1; 5 or A; B; C;...J can be supplied on request. One revolution of the
external operating handle is required for each tap change. The standard delivery of the
operating mechanism is a mechanical lock. When necessary, the operating mechanism with a
position transmitter for remote indicator may be ordered. To save the transformer against not a
load operation , a microswitch which is connected to the operating handle, may be also
ordered.

3
Standard Delivery of the tap-changer

* Tap Changer with or without barrier;

* 500 mm insulated cable ready crimped to each stationary contact (2880 wires, diameter
18,10 mm, paper insulation 1,04 mm single-side, cross section 150 mm²). Cable length
more than 500 mm can be supplied on request;
* Earthing cable;
* Drive shafts in fiberglass or steel;
* Interface to operating mechanism;
* Operating mechanism with: a) characteristic plate
b) mechanical lock

IMPORTANT
1) The coopling shaft beetwen the tap changers do not be assembled during drying
process of the active part. The insulating shaft must be drying separetly. If needed máx. 70°C.
2) After drying process of the active part, retighten and lock with insulating glue, all the
insulating nuts and fixing elements of the de-energized tap changers.

4
Electrical Data

 Current limit (steady state RMS value) with 10° C gradient to oil : 500 A
 Short circuit current limit (RMS value during 2 seconds) : 8540 A
 Maximun number of positions for each group : 10
 Maximun number of stationary contacts for each group : 11

Table of admissible voltage:

One minute power frequency lightning impulse (1.2/50 s)

[kV] [kV]
between adjacent contacts 51 194
to ground 275 650

5
Aplication

Bridging Diagram and Position Designation

The LC Tap Changer can bridge only adjacent stationary contacts.There are two types of LC
Tap Changers:
LC1 : Tap Changer with one contact group.
LC2 : Tap Changer with two contact groups, where the bridging of adjacent contacts are

provided simultaneous in both contact groups. See fig. 1

LC1 LC2

Winding Winding

Tap-changer Tap-changer

Figure 1 - Tap-changer Types

Standard configurations

Three standard configurations of LC frames and drive systems are available. The operating

mechanism may be ordered for mounting on either the left hand side (see figure 2a.) or

right hand side(see figure 2b.) of the transformer.

The stationary contacts may be ordered on either the left or the right side of the frames,

individually see figure 3.

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 Phase 1 Phase 2 Phase 3

Position 1

Phase 1 Phase 2 Phase 3

Position 2
Figure 2a - Operating Mechanism on Left Side

Phase 1 Phase 2 Phase 3

Position 2

Phase 1 Phase 2 Phase 3

Position 1
Figure 2b - Operating Mechanism on Right Side

VIEW "A"

View "A" View "A"

Right Side Left Side
Figure 3 - Stationary Contacts Location

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LC1/LC2 - One single deck frame and one double deck frame (3 decks total) connected with

one drive shaft and an interface shaft to one external operating mechanism. See figure 4a.

LC1/LC1/LC1 - Three single deck frames (3 decks total) connected with two drive shafts and

an interface shaft to one external operating mechanism figure 4b.

LC2/LC2/LC2 - Three double deck frames (6 decks total) connected with two drive shafts and

an interface shaft to one external operating mechanism figure 4c.

4a - LC1/LC2

4b - LC1/LC1/LC1

4c - LC2/LC2/LC2

Figure 4 - Standard Configurations

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Dimensions

Change-over units

The dimensions for change-over units are according to the following description and Figure
5a and Figure 5b

E : Axial distance between assembly points.

N : Quantity of stationary contacts.
V : Choosen according to assembly requirements (V = 148 mm minimum)
U : The minimum of this dimension depends on the quantity of contacts (see table 1).
Sometimes is necessary to increase this mechanical dimension according to the test
voltage to ground. The dimension required by the corresponding test voltage is given in
table 2 and table 3. According to assembly requirements any other dimension, bigger than
electrical or mechanical dimensions, can be choosen.
W : The minimum of this dimension depends on the test voltage between two groups of
contacts , and is given in table 2 and table 3. According to assembly requirements any
other dimension, bigger than electrical dimension, can be choosen. (Minimum mechanical
necessary is 60 mm).
F,M : Depending on the quantity of contacts. (see table 1)
 K1 , K2 : Distance between center lines of adjacents Tap Changers
steel drive shaft-diameter = 26.9mm fiberglass drive shaft-diameter = 35mm
K = 230 mm - Minimum length K = 230 mm - minimum length
K = 2000 mm - Maximum length K = 1550 mm - maximum length

NOTE: The sum of V + M + U for LC1 or V + 2xM + W + U for LC2 must be lower or equal
than 2180 mm. For LC2 bigger than 2180 must be choosen two tap changers type LC 1.

S : Distance from center line of Tap Changer to tank wall. This distance can be choosen

according to design requirements. Figure 5b

S = 280 mm minimum
S = 1500 mm maximum (up to 3 Tap Changers)
ALFA : Angle between drive shaft and interface. This angle can be choosen from 0° to
maximum 15°.
T : Lenght of the mounting boss. The interface can be ordered for two lenght of T.
T = 132 mm
T = 300 mm
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 LC1 LC2

2
2

1 Tolerance +/- 1 mm f or mounting

2 Grounded poi nt
3 Tolerance +/- 15 mm for mounting

F ig u re 5 a - D im e n s io ns fo r c h a n g e -o v er units

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 Transformer Shaft Bracket
Tank Wall
Mounting Boss
Change-over External
Center Line Operating
Mechanism
Interface Shaft Oil Air

Gasket

Figure 5 b - Dimensions for Operating Mechanism Connections

TABLE 1

MINIMUM MECHANICAL DIMENSIONS DEPENDING ON THE

QUANTITY OF THE CONTACTS
Number M F U H(min) H(min) H(max)
of LC1 LC2 LC1/LC2
Positions (mm) (mm) (mm) (mm) (mm) (mm)
2 168 108 216 680 908 2328
3 222 162 270 842 1124 2382
4 276 216 324 1004 1340 2436
5 330 270 378 1166 1556 2490
6 384 324 432 1328 1772 2544
7 438 378 486 1490 1988 2598
8 492 432 700 1812 2364 2652
9 546 486 754 1974 2580 2706
10 600 540 808 2136 ___ 2760

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 TABLE 2

MINIMUM ELETRICAL DIMENSIONS DEPENDING ON THE

LIGTHNING IMPULSE VOLTAGE (1.2/50 s)
Impulse Voltage [kV] U or W
(mm)
350 60
450 97
550 167
650 294

TABLE 3

MINIMUM ELETRICAL DIMENSIONS DEPENDING ON THE ONE -

MINUTE POWER FREQUENCY VOLTAGE (RMS)
Power Freq. Voltage [kV] U or W (mm)
110 60
140 94
185 150
230 230
275 350

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Operating Mechanism
The operating Mechanism is according to Figure 6

The mounting boss for operating Mechanism must be prepared by the usuer, according to

Figure 7

Tank Wall

Figure 7 - Dimensions for Operating Mechanism Mounting Boss

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Mass Calculation

1. DECK FRAME :
LC 1 with barrier
 ( 0.004 x U ) + ( 0.002 x V ) + ( 0.002 x M ) + ( 0.174 x N ) + 4.460

LC 1 without barrier
 ( 0.004 x U ) + ( 0.002 x V ) + ( 0.002 x M ) + ( 0.174 x N ) + 4.660

LC 2 with barrier
 ( 0.004 x U ) + ( 0.002 x V ) + ( 0.006 x M ) + ( 0.437 x N ) + (0.004 x W ) + 5.177

LC 2 without barrier
 ( 0.004 x U ) + ( 0.002 x V ) + ( 0.007 x M ) + ( 0.437 x N ) + (0.005 x W ) + 5.377

2. SUPPORTS
supports for LC 1 for U  500 mm  + 0.225 or for U  500 mm  + 1.123
+
for V  500 mm  + 0.225 or for V  500 mm  + 1.123

supports for LC 2 ditto LC 1

+
for W  500 mm  + 0.225 or for W  500 mm  + 1.123

3. DRIVE SHAFT BETWEEN CENTERLINES OF ADJACENTS TAP CHANGERS :

 steel drive shaft : ( 0.00160 x K ) - 0.1520 mass for 1 drive shaft
 fiberglass drive shaft : ( 0.00076 x K ) - 0.0684 mass for 1 drive shaft

4. INTERFACE SHAFT BETWEEN TAP CHANGER AND OPERATING MECHANISM :

 insulating interface shaft : {[( 0.0017 x S ) - 0.3162 ] / COS ALFA } + 2.200

5. OPERATING MECHANISM : 9.50 kg

note.: 1) supply the dimensions U,V,M,W,K,S in mm
2) N quantity of stationary contacts
3) supply the dimensions M and the quantity of N for only 1 group of contacts
4) mass in kg for all above calculation (add up the itens 1 , 2 , 3 , 4 , 5 )

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Recommendations for Positioning

Distances from contacts to earthed surfaces

The Table 4 is given the free oil distance from the Tap Changer to the ground side. The ground
side can be tank wall, windings, cables,etc.These distances are the minimum required to avoid
dieletrical over-stresses in the Tap Changer.

TABLE 4

With Barrier Without Barrier

D (mm) D (mm)
350 80 105
Impulse 450 120 180
Voltage [kV] 550 180 270
650 250 390

140 90 140
Power Freq. 185 130 200
Voltage [kV] 230 180 270
275 230 350

Distances from the frame and drive shaft to the leads

The Table 5 is given the minimum free oil distance from the Tap Changer frame and drive shaft
to the leads. D1 is independent of the connection's insulating.

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 TABLE 5

Impulse Voltage [kV] Power Freq. Voltage [kV] D1 ( mm )

265 100 70
398 150 105
490 185 130
610 230 180
729 275 265

The Figure 8a shows the distances configuration from tap-changer frames

The Figure 8b shows the distances configuration from tap-changer drive shaft.

Insulating Insulating
Drive Shaft Drive Shaft

8a - Connections position 8b - Connections position near to the

near Tap-changer frame insulating drive shaft of the Tap-changer

Figure 8 - Eletrical Distances

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17
 ORDERING DATA DELIVERY

ABB
DATE:
DE ENERGIZED / /
TAP CHANGER LC
Customer: Customer Ref: Quant. of Transformers: End Customer:

SPECIFICATIONS
Technical Guide acc. to 1ZBR 5499-101
Voltage limits, see technical guide 1ZBR 5499-101
NUMBER OF POSITIONS: Impulse Voltage (1,2 / 50 µs): Power Freq. Voltage:
To Ground: Between Groups: To Ground: Between Groups:

2. TYPE
Stationary contacts (right, left) and dimensions (U, V, W) must be filled on the table.

2.1 ( ) LC1/LC2 – One single deck frame and one double deck frame.
U V W K1 = [mm]  =  (max. 15)
( ) Right ----
LC1 S= [mm] (max. 1500 mm)
( ) Left
T= [mm] (132 or 300 mm)
( ) Right
LC2 Barrier: ( ) Yes ( ) No
( ) Left
2.2 ( ) LC1/LC1/LC1 – Three single deck frames.
( ) Right U V W K1 = [mm]  =  (max. 15)
LC1
( ) Left ---- K2 = [mm]
( ) Right S= [mm] (max. 1500 mm)
LC1
( ) Left ---- T= [mm] (132 or 300 mm)
( ) Right
LC1 Barrier: ( ) Yes ( ) No
( ) Left ----
2.3 ( ) LC2/LC2/LC2 – Three double deck frames.
( ) Right U V W K1 = [mm]  =  (max. 15)
LC2
( ) Left K2 = [mm]
( ) Right S= [mm] (max. 1500 mm)
LC2
( ) Left T= [mm] (132 or 300 mm)
( ) Right
LC2 Barrier: ( ) Yes ( ) No
( ) Left

3. DRIVE SHAFTS: Fiberglass: ( ) 230 mm  K  1550 mm Steel: ( ) 230 mm  K  2000 mm

4. OPERATING ( ) Right ( )1
Side: Position:
MECHANISM: ( ) Left ( )2
5. NAME PLATE: 6. REMOTE INDICATOR 7. MICROSWITCH
( ) English ( ) Yes ( ) Yes
( ) Spanish ( ) No ( ) No
( ) Portuguese
Special Requirements:

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