—
1ZSC000562-AAX EN, REV. 3
On-load tap-changers type VUC Technical guide
— Original instruction 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 ABB, or its authorized representative. We reserve the right to make technical changes or modify the contents of this document without prior notice. With regard to purchase orders, the agreed particulars shall prevail. ABB does not accept any responsibility whatsoever for potential errors or possible lack of information in this document. We reserve all rights in this document and in the subject matter and illustrations contained therein. Any reproduction, disclosure to third parties or utilization of its contents – in whole or in parts – is forbidden without prior written consent of ABB.
— Table of contents Design principles On-load tap-changer (OLT (OLTC) C) Diverter switches Tap selectors Design differences across the VUC range of on-load tap-changers Diverter switch housing and top section Painting Operating mechanism Transition resistors Special applications, load conditions, and environments Insulating liquids Special designs Motor-drive mechanism Accessories
Principles of operatio operation n Switching sequence, VUCG
6
Oil temperature
6 8 9
Alternative liquids Coarse/fineinsulating regulation leakage inductance 29 switching 30 Tie-in resistor and tie-in resistor switch 30
10 10 10 11 11 11 11 11 11 11
12 12
Switching sequence, VUCL Type of regulation Linear switching (type L) Change-over selector for plus/minus switching (type R) Change-over selector for coarse/fine switching (type D) Type of connection Three-phase neutral point (N) Single-phase (E) Three-phase delta (B) Three-phase fully insulated, delta (T)
14 16 16
Characteri stics and technical data Characteristics Type designation Type of tap-changer Type of regulation Type of connection Impulse withstand voltage to earth Maximum rated through-current Tap selector size Tap selector shielding Enforced current splitting Rated phase step voltage Coarse fine regulation leakage inductance switching Contact life Standards and testing Rating plate Insulation levels Withstand voltages Short-circuit current strength Highest phase service voltage across the regulating winding Rated through-current
18 18 18 18 18 18 18 18 18 20 21
Occasional overloading
16 16 17 17 17 17 17
23 23 23 23 24 25 28 28 29 29
29
Installation and maintenance Tap-changer Installation Drying Weights Oil filling Maintenance Pressure Accessories and protection devices Motor-drive mechanism Design Installation Maintenance
32 32 32 32 32 32 32 32 32 34 34 34 34
Operating shafts Dimensions Dimensions, type VUCG Dimensions, type VUCL Oil conservator
34 36 36 41 47
Appendices:
48
Single-phase diagrams
48
Manufacturer’s declaration The manufacturer
ABB AB Components SE-771 80 LUDVIKA Sweden
Hereby declares that The products
On-load tap-changers, type VUC with motor-drive mechanisms, types BUE and BUL
comply with the following requirements:
By design, the machine, considered as a component of a mineral oil filled f illed power transformer transformer,, complies with the requirements of •
Machinery Directiv Directive e 89/392/EE 89/392/EEC C (am (amended ended 91/368 91/368/EEC /EEC and 93/ 93/44/EEC) 44/EEC) and 93/68 93/68/EEC /EEC (marking) provided that the installation and the electrical elec trical connection are correctly realized by the manufacturer of the transformer (e.g. in compliance with our Installation Instructions) and
•
EMC Dir Directive ective 89 89/336/EEC /336/EEC regarding the intrinsic characteristics to em emission ission and imm immunity unity levels and
•
Low Voltage Directive 73 73/23/EEC /23/EEC (modified by Directive 93/68 93/68/EEC) /EEC) c concerning oncerning 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 has been declared in conformity with the Machinery Directive. Date
2018-02-01
Signed by ................ ................................. ................................. ................................. ........................ .......
Peter Hamne
Title
Manager Tap Tap-Changers, -Changers, Local Product Group Unit Components
6
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
— Design principles
On-load tap-ch anger (OLT (OLTC) C) VUC vacuum diverter switch tap-changer family comes in a range of models with ratings suitable for the most frequent transformer applications. The VUC types of tap-changers are usually mounted inside the transformer tank, suspended from the transformer cover. VUC tap-changers is built on the same platform as the conventional UC tap-changers and shares the well proven selectors, diverter switch housings and drive train. This design consists of two separate sections: the diverter switch, which has its own housing separate from the rest of the transformer, and the
tap selector. The tap selector, which is mounted beneath the diverter switch housing, consists of the fine tap selector and usually also of a changeover selector. Power to operate the tap-changer is supplied from the motor drive mechanism, which is mounted on the outside of the transformer. The power is transmitted by means of shafts and bevel gears. The VUC diverter switches, with arc quenching in vacuum interrupters, contaminates it’s insulating liquid slightly due to current commutation sparks and heat dissipation from the transition resistors therefore it’s insulating liquid is kept separated from the oil in the transformer to not influence the oil analysis of the main transformer tank.
Oil conservator Shaft
Bevel gear Transformer cover
Transformer tank
Diverter switch
On-load tap-changer Shaft
Tap selector
Motor-drive mechanism
— 01 Main parts, on-load tap-changers type VUC.
7
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Buffer springs Cover
Bevel gear with position indicator
Lifting eyes
Connection flanges (x4)
Flange for connection to gas operated relay (transformer main tank)
Top section
Shielding-ring
Insulating shaft
Oil draining tube
Shielding-ring Diverter switch
Transition Transitio n resistors
Insulating cylinder
Plug-in contacts Main vacuum interrupters
Guide pins
Driving disc for the diverter switch
Bushings connecting from the tap selector
Spring drive mechanism Valve for use at processing
Intermediate gear Bottom section
Current terminal
— 02 Diverter switch, type VUCG, with housing.
8
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Diverter switches The diverter switches with vacuum interrupters are of the high-speed, spring-operated type with resistors as transition impedance. They are equipped with plug-in contacts that automatically connect to the bushings in the diverter switch housing when the switch is lowered into the housing. Guiding facilities keep the diverter switch in the correct position when lowering it into the housing. Mechanical coupling to the drive is easily established by making three operations in the same direction. The design and dimensioning of the diverter switches offer high reliability and long life with a minimum of maintenance and easy inspection. A diverter switches with vacuum interrupters combine all the advantages of the conventional type with improved breaking capacity, increased contact life and reduced maintenance. The switch works according to the pennant cycle, which gives the lowest complexity 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, independently of RAISE or LOWER command. The load is commutated from one tap to the other with the aid of the vacuum interrupters and auxiliary contacts. The auxiliary contacts are also able to break the load current in the unlikely event
— 03 Examples of diverter switches VUCG and VUCL.
that a vacuum interrupter failure should occur. For VUCG in service position, the load current is transferred through through the auxiliary contacts and the vacuum interrupters. All current carrying contacts are made of low resistance material. For VUCL in service position, the load current is transferred through a bypass contact. The contact system is operated by a compact mechanical system with integrated driving springs, mechanical rectifier, robust mechanical system for vacuum interrupter actuating and geneva gears for operating the auxiliary contacts and the by-pass contact ( VUCL). All manufactured UCG, UCL.N/B and most of the UCL.E/T ≤1300 A diverter switches can be easily replaced by the vacuum diverter switch and gain benefit from the improvements made on this type. The VUCG diverter switch fits all UCG tapchangers as manufactured 1977 and later w ithout modification, which enables all UCG tap- changers to be easily upgraded to vacuum technology. The VUCL diverter switch fits all UCL housings manufactured 1985 and later without modification. Due to the specially designed and robust vacuum interrupters, developed and tested in ABB’s unique test facility for vacuum type tap-changers, operation of vacuum interrupters in parallel makes it possible to offer vacuum type tapchangers for currents up to 2400 A in singlephase applications.
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Tap selectors Although the tap selectors for the VUC range of tap-changer are available in various sizes, all of them 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 or more contact arms in parallel with one, two, four or eight 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 conductivity and negligible contact wear. The tap selectors available for the VUC range of tap-changers are C, III and F. Tap selector C can be combined with VUCG diverter switches. Tap selectors III and F can be combined with both VUCG and VUCL. All tap selector types use a complete, un-divided glass fiber reinforc reinforced ed epoxy cylinder for the fine selector. The change-over selector contacts are all made of silver for high long-time stability and resistance against fretting.
— 04 Tap selectors: size C, size III and size F.
9
10
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Design differences across the VUC range of onload tap-changers The VUC range of tap-changers consists of two diverter switches and three tap selectors.
The bottoms and heads of the cylinders are made of cast aluminum. The drive shafts and bevel gears are placed beside the diverter switch cylinders, thereby providing easy access to the diverter switches.
The diverter switches are VUCG and VUCL. Both have arc quenching in vacuum interrupters. In VUCG the load current goes continuously through the vacuum interrupters, while VUCL has a bypass contact for the load current when not operating. Diverter switch housing and top section The top section forms the flange that is used for mounting to the transformer cover, and for carrying the gear box for the operating shafts. The top section includes a connection for the conservator pipe, draining and sampling 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 seals that guarantee vacuum and overpressureproof performance under all service conditions. In case of material ageing after extremely long service the seals can be re-tightened from the inside of the housing.
VUCG.N/C 650 kV short
VUCG.N/III 650 kV
1
2
3
L (m) — 05 On-load tap-changers type VUC , size comparison.
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 drain 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 glass fiber reinforced epoxi. The bushings through the cylinder wall are sealed by O-ring gaskets with elastic pressure. Each readymade 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 color, Munsell 5,5 B 5,5/1,25, corrosion class C3 according to SS-EN ISO 12944 -2 and SS-EN ISO 9223. For corrosion classes such as C4 or C5, or higher, please contact ABB for further informatio information. n.
VUCG.N/F 650 kV
VUCL.N/III 650 kV
VUCL.N/F 650 kV
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Operating mechanism The bevel gear, mounted on the top section flange transfers the drive from the motor-drive mechanism, via the vertical insulated shaft, to the intermediate gear for the diverter switch and the tap selector. From the intermediate gear, a drive shaft transfers the energy to the diverter 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 easily re-connected by a simple procedure that ensures that the drive shaft and the guide pin of the diverter mechanism are correctly aligned.
11
Special applications, load conditions, and environments Please contact ABB for advice in the following cases: • For non-network applicatio applications. ns. (Limita (Limitations tions in number of operations per time might be given.) • In case of unusual load conditions such as overloads beyond IEC 60076-7, 2005-12, or IEEE C57.91-2011, extreme inductive or capacitive loads or loads beyond the given data in this document. • Current measurement in phase before neutral point. • Applicat Applications ions for reactors.
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.
Insulating liquids All data in this guide is based on the use of mineral oil according to IEC 60296, 2012-02. Other liquids, such as esters and HMWH are accepted under certain conditions. Please consult ABB for advice.
The external drive shaft, which does not need to be removed during maintenance work, minimizes the risk of misalignment in the system. However a
Special designs On request, the VUC tap-changers are also available for regulation with bias winding and for
mechanical end limit stop for the tap selector is available on request. Special shaft systems are also available on request.
Y/D regulation.
Transition resistors The transition resistors are made of wire and located above the diverter switch contacts. The resistors are robust and designed to last the lifetime of the mechanism under normal service conditions.
Motor-drive mechanism The motor-drive mechanism provides the drive to allow the 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. Accessories For a list of accessories available for both the tapchangers and the motor-drive mechanisms, contact ABB.
12
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
— Principles of operation
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. The switching sequence is that for an assymetrical pennant cycle always going with the main contact first (called diverter switch with one transition resistor resistor #1 in IEC 60214-1, 2014-05). Fig. 6 shows the current path during normal operation, from x to the neutral 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. 7. The main contact (MC) is then rotated (Figs. 8 and 9) 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. 10. The load current is now via the normal path from v to the neutral point. The voltage is now changed one step. In Fig. 11, the transition resistor is disconnected when opening the resistor vacuum interrupters (RVI). The resistor contact (RC) is then rotated and put in position according to Fig. 12. Finally, the sequence is completed and next service position is fully reached when the resistor vacuum interrupter is closed, see Fig. 13. The sequence in Figs. 06-13 shows one pole only. For VUCG.E/T, three such operates in parallel. The single phase diagrams are available in the appendices, pages 47-65.
13
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
TR
RVI MC
RC
RC
v
— 06
— 10
x
MVI
TR MC
RVI
RC
v
— 07
— 11
x
MVI
TR
RVI
MC RC
v
— 12
— 08
x
MVI
TR MC
RC
v
— 09
— 06-13 Switching sequence, VUCG.
— 13
RVI
14
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Switching sequence, VUCL By using an auxiliary contact system (MC, RC) in combination with the vacuum interrupters (MVI, RVI) only two vacuum interrupters are required per phase. The switching sequence is that for an assymetrical pennant cycle always going with the main contact first (called diverter switch with one transition resistor resistor #1 in IEC 60214-1, 2014-05). Fig. 14 shows the current path during normal operation, from x to the neutral 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 bypass contact (BPC), Figs. 15 and 16. Next is to open the main vacuum interrupter (MVI) and hence let the current flow through the transition resistor (TR), Fig. 17. The main contact (MC) is then rotated (Figs. 18 and
19) 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. 20. The load current now goes from v to the neutral point. The voltage is now changed one step. The bypass contact is then connected to v (Figs. 21 and 22). The load current is now via the normal path from v to the neutral point. In Fig. 23, the transition resistor is disconnected when opening the resistor vacuum interrupter (RVI). The resistor contact (RC) is then rotated (Fig. 24) and makes to the v-side. Finally, the sequence is completed and next service position is fully reached when the resistor vacuum interrupter is closed, see Fig. 25. The sequence in Figs. 14-25 shows one pole only. For VUCL.E and .T, three poles operate in parallel.
x
x
MVI
TR
BPC MC
RVI
MVI
TR
BPC MC
RC
v
RVI
RC
v
— 14
— 16 x
x
MVI
TR
BPC MC
RVI
MVI
TR
BPC MC
RC
v
RC
v
—
—
15
17
RVI
15
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
x
x
MVI
TR
BPC
RVI
MVI
RC
MC
TR
RVI
BPC MC
v
RC
v
— 22
— 18 x
x
MVI
TR
BPC MC
RVI
MVI
TR
RVI
BPC MC
RC
v
RC
v
— 23
— 19 x
x
MVI
TR
BPC MC
RVI
MVI
TR
RVI
BPC RC
RC
MC
v
v
— 24
— 20 x
x
MVI
TR
BPC MC
RVI
MVI MC
RC
v
RC
v
—
—
21
25
— 14-25 Switching sequence, VUCL.
TR BPC
RVI
16
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
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. 26. 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 w inding to different ends of the regulating winding, and thereby reversing the magnetic flux generated by the regulating winding. See Fig. 27.
— 26 Linear switching (type L).
Change-over selector for coarse/fine switching (type D) In type D switching the change- over selector extends the regulating range to twice the voltage of the tapped winding, by connecting or disconnecting the coarse regulating winding. Fig. 28.
— 27 Change-over selector for pl us/minus switching (type R)
Change-over selector, coarse/fine
— 28 Change-over selector for coarse/fine switching (type D)
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Type of connection Three-phase neutral point (N) Only one unit is required for all three phases. The transformers neutral point is in the tap-changer. Single-phase (E) Only one unit is required. Three-phase delta (B) Two units required. Driven by a common motordrive. One unit common for two phases.
— 29 Three-phase neutral point (N)
Three-phase fully insulated, delta (T) Three units required. Driven by a common motordrive.
— 30 Single-phase (E)
— 31 Three-phase delta (B)
— 32 Three-phase fully insulated, delta (T)
17
18
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
— Characteristics and technical data
Type designation
VUCG VUCL Example VUCGRE 650/700/C Type of tap-changer VUC... Diverter switch with vacuum interrupt interrupters ers Type of regulation L Linear R Plus/Minus D Coarse/Fine Type of connection N Three- phase neutral 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 VUCG: 380 kV kV,, 650 kV, 750 kV, 1050 kV VUCL: 380 kV, 650 kV kV,, 750 kV, 1050 kV, 1175 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 VUCG only III tap selector for VUCG and VUCL F tap selector for VUCG and VUCL Tap selector shielding us unshielded s shielded
. . XXXX/Y YY Y/Z . . . XXXX/Y YY Y/Z .
19
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
— Table 1. Diverter switches Type
M a x . r a te d t h r o u g h - c u r re n t
VUCG.N, B
), ), , A
VUCG.E, T
), ), , , ), ), ), ) A
VUCL.N, B
, , A
VUCL.E, T
, , , , , A
VUCL.E, T (enforced current splitting)
x ), x, x A
1) Short version available in certain intervals, see Fig. 33. For dimensions, see Table Table 18. 2) Only available in E, T connection and requires enforced current splitting during operation, see that section. Contact ABB for more information.
— Table 2. Tap selectors Type
Co nn e c t i o n
M a x . r a te d t h ro u g h - c u rr e n t
M a x i m p u l s e t e s t vo l t a g e a c r o s s r a n g e
C
N, B
A
kV )
E, T
, , A
kV )
N, B
A
kV )
E, T
, , A
kV )
N, B
A
kV
E, T
, A
kV
I II
F
1) Note that for certain positions, these values are lower. lower. See Insulating levels. levels.
— Table 3. Possible combinations of diverter switches and ta p selectors Diverter switch VU CG
V UCL
Tap sel ec tor C
x
n.a .
Tap sel ec tor I II
x
x
Tap sel ec tor F
x
x
— Table 4. Maximum number of positions Typ ype e of swi switc tchi hing ng
Tap sele select ctor or
Max. number of positions
Li n e a r
C
III
F
C
III
F
C
III F
Pl us/minus
Coarse/f ine
20
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Enforced current splitting In certain applications, two or more poles of a tap-changer, or more than one tap-changer can work in parallel. However, it is important to implement this in a correct way. There is a difference between whether it should work in position (not during operation) only or if it should work during operation. If the current split is only needed in position, a weaker current split will work. By having the same number of conductors in parallel through the windings as there are poles or tap-changers in parallel, parallel working 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 tap-changers must not exceed the rating of any of them. The reason is that the poles in the diverter switch or the diverter switches do not operate at exactly the same time.
To achieve this impedance, it is normally required that the parallel conductors 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 splitting during operation should be made use of. If the parallel conductors are located in separate parallel limbs (for single-phase transformers), the current split will be very strong. A strong current split may also be achieved if the parallel conductors are located in different coils in an axial split winding. Unless the parallel conductors are on separate parallel limbs, the impedance between parallel conductors must be calculated by the transformer manufacturer, when enforced current splitting during operation should be made use of. See also IEC 60214-2, 2004 -10, para paragraph graph 6.2.9 for information.
21
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
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 diagrams below. VUCG in the short version has a 220 mm shorter diverter switch housing, see dimension drawings
) V ( e g a t l o v p e t S
in this document. For short versions, there might be restrictions in applications other than network. For industrial applications or any other application where the number of operations is expected to exceed 100 operations per day, certain exceptions might apply, see product information 1ZSC000498-ACM.
3500
3000
2500
2000
VUCG.N,B Short version available
1500
VUCG.N,B *) For short version, please consult ABB for advice.
1000
500
*)
0 0
100
200
300
400
500
600
700
800
Rated through-current (A)
) V ( e g t a l o v p e t S
3500
VUCG.E,T
3000
2500
2000
VUCG.E,T Short version available
1500
1000
500
*) 0 0
100
200
300
400
500
600
700
800
90 00 0
10 00 00 11 10 00
12 20 00
13 30 00
1 40 40 0 1 5 50 00 16 60 00
17 70 00
18 80 00
Rated through-current (A)
— 33 Rated phase step voltage for type VUCG.
22
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
) V ( e g a t l o v p e t S
6000
5500 5000
4500
4000
3500
VUCL.E,T 3000
2500
2000
1500
1000
500
0 0
100
200
300
400
500
600
700
800
900 900
1 00 00 0 1 1 0 00 0
1 20 20 0
1 30 30 0
1 40 40 0
15 50 00
16 60 00
1 70 70 0
18 80 00
19 90 00
20 00 0 0 2 1 00 00
2 20 20 0 2 30 30 0 2 40 40 0
Rated through-current (A)
) V ( e g a t l o v p e t S
4500
4000
3500
3000
2500
VUCL.N,B 2000
1500
1000
500
0 0
100
200
300
400
500
600
700
800
9 00 00
10 00 00 11 10 00
12 20 00
13 30 00
Rated through-current (A)
— 34 Rated phase step voltage for type VUCL
23
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Coarse fine regulation leakage inductance switching When operating from the ends of the fine or the coarse winding a high leakage inductance might appear, causing a phase shift between the switched current and the recovery voltage. This value has to be given when ordering a tapchanger so that proper dimensioning is possible. The leakage inductance value can be given in the order data sheet or can be calculated by ABB from active part dimensions and number of turns. For more information, information, see IEC 60214- 2, 2004-10, or product information 5492 0031-100. For most transformer designs, even those with axially located windings, the values are normally not exceeding the limits for VUC due to the excellent breaking performance of the vacuum interrupters. It shall however be calculated for every case.
Contact life The contact life is 600 000 operations, regardless of the rated through-current. The contact life for VUCG.E,T might be reduced in some applications. The contact life is stated on the rating plate, see Fig. 35. Standards and testing The on-load tap-changers made by ABB fulfill the requirements according according to IEC 60214-1, 2014-05, and IEEE C57.131-2012. The type tests include: • Contact temperature rise test • Switching tests • Short-c Short-circuit ircuit current test • Transition impedance test • Mechanical tests • Dielectric tests The routine tests include: • Check of assembly • Mechanical test • Sequence test • Auxiliary circuits ins insulation ulation te test st • Vacuum test • Final inspection Rating plate
(2014-05) Maintenance after 300 000 operations (guideline: 15 years). Inspection once a year.
— 35 Example of rating plate.
24
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Insulation levels LI is the lightning impulse (1.2/50 µs), and Pf is the power frequency test voltage (60 s). The insulation levels are indicated as impulse withstand voltage – power frequency withstand voltage.
b1
Corresponding contact in adjacent phase a2
The tests were carried out according to IEC 60214-1, 2014-05, with a new tap-changer and clean insulation transformer oil LC set -30 °C according to IEC 60296, 2012-02. The withstand voltage value of the oil was higher than 40 kV/2.5 mm (IEC 60156, 1995- 08).
b2
e1
g1 a1 b1
Insulation levels to earth (g1) For VUC
- kV, - kV, - kV, - kV, and - kV
— 26 Linear switching (type L).
Corresponding
Lightning impulse impulse levels (LI) and power frequency levels (Pf ) corresponds to the following Um -values acc. to IEC:
contacts in adjacent phase
— Table 5. Insulation levels.
b1
LI ( kV )
P f ( kV )
Um (kV)
. )
a2
a1
b2
e1
g1
1) Covers 76 kV that is not an IEC value. b1
a1 Between any electrically electrica lly adjacent contacts in the tap selector, not connected. a2 Between the ends of the fine regulating windin winding g ((across 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 of different phases in the fine selector b2 Between open contacts of differen differentt phases in the diverter switch. switch. c1 Between ends of the the coarse winding in coarse/ coarse/fine fine switching d1 Between taps of different phases in the coarse selector (coarse/ fine switching) e1 Between pre-selected tap and connected tap of of one phase in the diverter switch and in the tap selector. f1 Between any end of the coarse winding and connected tap f2 Between any end of of the coarse winding and the midd middle le of the fine winding. g1 Connecte Connected d tap to earth g2 Pre-selected tap to earth
— 27 Change-over selector for pl us/minus switching (type R).
Corresponding contacts in adjacent phase d1 c1
d1
f2 a2
a1
f1
e1
b2 g2
g1
b1
— 28 Change-over selector for coarse/fine switching (type D).
25
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Withstand voltages — Table 6. VUCG with tap selector C All values given as 1.2/50 μ s 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.
W it h i n o n e p h a se
B et we en ph ase s for n eutral poi nt
Type of reg regulat ulation ion
No. of pos positi itions ons a2
c1
f1
f2
e1
b2
b1
d1
L
-
-
-
-
-
-
-
-
-
L
-
-
-
-
-
-
-
-
-
L
-
-
-
-
-
-
-
-
-
R
-
-
-
-
-
-
-
-
-
R
-
-
-
-
-
-
-
-
-
R
-
-
-
-
-
-
-
-
-
R R
- -
- -
-
-
-
- -
- -
- -
-
D
-
-
-
-
-
-
-
-
-
D
-
-
-
-
-
-
-
-
-
D
-
-
-
-
-
-
-
-
-
D
-
-
-
-
-
-
-
-
-
D
-
-
-
-
-
-
-
-
-
— Table 7. 7. VUCG with tap selector III unshielded version All values given as 1.2/50 µs impulse withstand voltage (kV) – power frequency withstand voltage (kV).
W it h i n o n e p h a se
B e t w e e n p h a se s f o r n e u t r a l p o i n t
Type of reg regulat ulation ion
No. of pos positi itions ons a1
a2
c1
f1
f2
e1
b2
b1
d1
L
-
-
-
-
-
-
-
-
-
-
L
-
-
-
-
-
-
-
-
-
-
L
-
-
-
-
-
-
-
-
-
-
R
-
-
-
-
-
-
-
-
-
-
R
-
-
-
-
-
-
-
-
-
-
R
-
-
-
-
-
-
-
-
-
-
R
-
-
-
-
-
-
-
-
-
-
R
-
-
-
-
-
-
-
-
-
-
R
-
-
-
-
-
-
-
-
-
-
D
-
-
-
-
-
-
-
-
-
-
D
-
-
-
-
-
-
-
-
-
-
D
-
-
-
-
-
-
-
-
-
-
D
-
-
-
-
-
-
-
-
-
-
D
-
-
-
-
-
-
-
-
-
-
D
-
-
-
-
-
-
-
-
-
-
26
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
— Table 8. VUCG with tap selector III shie lded version All values given as 1.2/50 µs impulse withstand voltage (kV) – power frequency withstand voltage (kV).
W i t h i n o n e p h a se Type of reg regulat ulation ion No. of pos positi itions ons a1 a2
B e t w e e n p h a s e s fo r n e u t r a l p o i n t c1
f1
f2
e1
b2
b1
d1
L
-
-
-
-
-
-
-
-
-
-
L
-
-
-
-
-
-
-
-
-
-
L
-
-
-
-
-
-
-
-
-
-
R
-
-
-
-
-
-
-
-
-
-
R
-
-
-
-
-
-
-
-
-
-
R
-
-
-
-
-
-
-
-
-
-
R
-
-
-
-
-
-
-
-
-
-
R
-
-
-
-
-
-
-
-
-
-
R
-
-
-
-
-
-
-
-
-
-
D
-
-
-
-
-
-
-
-
-
-
D
-
-
-
-
-
-
-
-
-
-
D
-
-
-
-
-
-
-
-
-
-
D
-
-
-
-
-
-
-
-
-
-
D
-
-
-
-
-
-
-
-
-
-
D
-
-
-
-
-
-
-
-
-
-
— Table 9. VUCG with tap selector F All values given as 1.2/50 µs impulse withstand voltage (kV) – power frequency withstand voltage (kV).
W it h i n o n e p h a se
B e t w e e n p h a se s f o r n e u t r a l p o i n t
Type of reg regulat ulation ion
No. of pos positi itions ons a1
a2
c1
f1
f2
e1
b2
b1
d1
L
-
-
-
-
-
-
-
-
-
-
R
-
-
-
-
-
-
-
-
-
-
D
-
-
-
-
-
-
-
-
-
-
27
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
— Table 10. VUCL with tap selector III unshie lded version All values given as 1.2/50 µs impulse withstand voltage (kV) – power frequency withstand voltage (kV).
Type of reg regulat ulation ion
W it h i n o n e p h a se No. of pos positi itions ons a1
a2
B e t w e e n p h a se s f o r n e u t r a l p o i n t c1
f1
f2
e1
b2
b1
d1
L
-
-
-
-
-
-
-
-
-
-
L
-
-
-
-
-
-
-
-
-
-
L
-
-
-
-
-
-
-
-
-
-
R
-
-
-
-
-
-
-
-
-
-
R
-
-
-
-
-
-
-
-
-
-
R
-
-
-
-
-
-
-
-
-
-
R
-
-
-
-
-
-
-
-
-
-
R
-
-
-
-
-
-
-
-
-
-
R
-
-
-
-
-
-
-
-
-
-
D
-
-
-
-
-
-
-
-
-
-
D
-
-
-
-
-
-
-
-
-
-
D
-
-
-
-
-
-
-
-
-
-
D
-
-
-
-
-
-
-
-
-
-
D
-
-
-
-
-
-
-
-
-
-
D
-
-
-
-
-
-
-
-
-
-
— Table 11. VUCL with tap selector III shielded version All values given as 1.2/50 µs impulse withstand voltage (kV) – power frequency withstand voltage (kV).
W it h i n o n e p h a se
B e t w e e n p h a se s f o r n e u t r a l p o i n t
Type of reg regulat ulation ion
No. of pos positi itions ons a1
a2
c1
f1
f2
e1
b2
b1
d1
L
-
-
-
-
-
-
-
-
-
-
L
-
-
-
-
-
-
-
-
-
-
L
-
-
-
-
-
-
-
-
-
-
R R
- -
- -
- -
-
-
-
- -
- -
- -
-
R
-
-
-
-
-
-
-
-
-
-
R
-
-
-
-
-
-
-
-
-
-
R
-
-
-
-
-
-
-
-
-
-
R
-
-
-
-
-
-
-
-
-
-
D
-
-
-
-
-
-
-
-
-
-
D
-
-
-
-
-
-
-
-
-
-
D
-
-
-
-
-
-
-
-
-
-
D
-
-
-
-
-
-
-
-
-
-
D
-
-
-
-
-
-
-
-
-
-
D
-
-
-
-
-
-
-
-
-
-
— Table 12. VUCL with tap selector F All values given as 1.2/50 µs impulse withstand voltage (kV) – power frequency withstand voltage (kV).
W it h i n o n e p h a se
B e t w e e n p h a se s f o r n e u t r a l p o i n t
Type of reg regulat ulation ion
No. of pos positi itions ons a1
a2
c1
f1
f2
e1
b2
b1
d1
L
-
-
-
-
-
-
-
-
-
-
R
-
-
-
-
-
-
-
-
-
-
D
-
-
-
-
-
-
-
-
-
-
28
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Short-circuit current strength The short circuit current strength is verified with three applications of 3 seconds duration 1), without moving the contacts between the three applications. Each application has an initial value of at least 2 .5 times the rms value. — Table 13. Short-circuit current strength D iv iver tte e r sw iittch
Ta p se lle ec tto or
V UCG
V UCL
Max rated through-current, A rm s
Ty pe of con n ec tion
3 s duration, kA rms )
Peak value, kA
C
,
N,B,E,T
C
, , ,
E,T
C
E,T
III
, , ,
N,B,E,T
III
E,T
III
, ,
E,T
F
, , ,
N,B,E,T
F
, , ,
E,T
II I
,
N,B,E,T
III
, , ,
E,T
F
, ,
N,B,E,T
F
, ,
E,T
1) For times longer than 3 s, contact ABB for advice. 2) In case of VUC..E,T higher values are possible on request.
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 14. Highest permissible phase service voltage across the regulating winding. Tap-changer and tap selector
A c ro s s t h e r e g u l a t i n g w i n d i n g ( kV ) w it it h co nt nt ac ac t s h hii el el di di ng ngs w it it h ho ou utt c on on tta a ct ct s hi hi el el d dii ng ng s
A c r o s s t h e co a r s e a n d f i n e w i n d i n g ( k V ) w it it h co n ntta ct ct s hi hi el el d dii ng ng s w it it h ho ou utt c on on ta ta ct ct s h hii e ell di di ng ng s
V UCG . N, B
C
-
-
V UCG . N, B
I II
V UCG . N, B
F
-
-
V UCL . N, B
I II
V UCL . N, B
F
-
-
V UCG .T, E
C
-
-
V UCG .T, E
I II
VU CG .T, E
F
-
-
)
VU CL .T, E
I II
V UCL .T, E
F
-
-
1) Higher values available on request. Please contact ABB.
29
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Rated through-current The rated through-current of the tap-changer is the current that the tap-changer is capable of transferring from one tapping to the other at the relevant rated step voltage, and which can be carried continuously whilst meeting the technical data in this document. The relation between rated through-current and step voltage is shown in Figs. 33-34. The rated through-current determines the dimensioning of the transition resistors. The rated through-current is stated on the rating plate, Fig. 39.
Oil temperature Provided that insulating oil of class “Transformer oil -30 °C” according to IEC 60296, 2012-02, is used, the temperature of the oil surrounding the tap-changer shall be between -25 and +105 °C for normal operation, as illustrated in Fig. 40. VUCG and VUCL can go to lower oil temperature than -25 °C if low viscosity oil is used; see Fig. 39, section 4.
Occasional overloading If the rated through-current of the tap- changer is not less than the highest 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.
1ZSC000498-ACM.
To meet these requirements, the VUC 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.
For tap-changers in applications with >100 >100 operations/day, thermal monitoring is recommended. See product information
Alternative insulating liquids Individual brands need to be evaluated from case to case because of the differences in viscosity compared to transformer grade mineral oil and the subsequent difference in heat dissipation. Also dielectric strengths and influence from moisture need to be considered. Please contact ABB for more information.
°C
+115
1.
No operations allowed.
2.
Emergency overloading overloading.. The tapchanger will not restrict the occasional
The contact life stated on the rating plate is given with the consideration that currents of maximum 1.5 times the rated through current occur in a maximum of 3 % of the tap -change operations. Overloading beyond these values, results in increased contact wear and shorter contact life.
+105
For more information about overloading, read the appropriate appropriat e parts of I EC 60214-2, 2004 -10.
0
-25
overloading of the transformer according to the standards stated in section Occasional overloading. 3.
Normal operating range.
4.
Operation possible under certain conditions. Please contact ABB for advice.
5.
No operation allowed.
-40
— 39 Oil temperature.
30
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
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 windings in series. The critical moment occurs at switching the tap-changers mechanical mid-position, as the circulating current passes through not only one loop but also the entire coarse and fine tap winding. The leakage inductance that occurs from one loop, Fig. 40, is negligible but can be substantial from the complete coarse and fine winding, Fig. 41. This leakage inductance causes a phase shift between switching current and recovery voltage that makes the breaking more severe. The tapchanger must be dimensioned accordingly. The leakage inductance shall be specified in the ordering data sheet. For certain winding configurations configurations,, such a s coarse and fine windings located axially, this value might be very high. For more information, see IEC 60214-2, 2004-10, or consult ABB for advice.
Tie-in resistor and tie-in resistor switch When the change-over selector operates, the tapped winding is disconnected 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. 42.
The tie-in resist resistor or is connected between the middle of the tapped winding and the connection point on the bottom of the diverter switch housing. 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 separately from the tap-changer but can be mounted under the tap selector provided that tie-in resistor switch is not used. Please contact ABB for advice in such cases.
Main winding
Main winding
Coarse winding
Coarse winding
Fine winding
Fine winding
— 40 Normal operation.
— 41 Operation with higher leakage inductance.
31
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
The following limits apply to the change- over selectors of the different tap selectors:
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 only for tap selector III and F. F.
— Table 15.
Tap selector
Max recovery voltage (kV rms)
Max capacitive current (mA rms)
C
III
F
F
When ordering, give the winding layout and information according to the example in Fig. 43 and Table 16, and ABB will calculate whether tie-in resistors are needed or not. If needed, ABB will choose the correct tie-in resistors. If a tie -in resistor switch is needed to limit the no-load losses, give that information in the ordering data sheet. If anything is unclear unclear,, contact ABB.
The capacitive current is the current going through the change-over selector before it opens. In Fig. 42 there is a switch, the tie-in resistor switch, which 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.
— Table 16. Example of winding layout and information. Win din g
P h a s e vo l t a g e
Co n n e c t i o n
High voltage (HV)
kV (H)
Delta
Regulating winding (RW) (Voltage across) . kV (U)
Plus/Minus
C = . nF (Capacitance between HV and RW) C = . nF (Capacitance between tank and RW) Frequency Hz.
Main winding
Diverter switch
Tank
Tie-in resistor switch
H1
U RW
HV Regulating winding with change-over selector
Tap Tap selector Tie-in resistor
C1
+
— 42 Tie-in resistor example.
— 43 Example of winding l ayout and information.
C2
-
32
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
— Installation and maint maintenance enance
Tap-changer Installation The tap-changers can be delivered for covermounting or yoke-mounting onto the transformer. For detailed installation instructions, consult the appropriate Installation and commissioning guide. Drying The tap-changer must be stored indoors and left in its plastic shipping cover until time for assembly. The tap-changer should be subjected to drying before taken into service. The diverter switch can participate in the drying process. If the diverter switch has participated in the drying process it is important that it is not maneuvered until it has been submersed in oil, not even hand operated. For further instructions refer to the Installation and commissioning guide. Weights Tables 16 and 17 show the approximate weights of the VUC range of tap-changers. Oil filling For details of oil filling, consult the appropriate Installation and commiss commissioning ioning guide. Maintenance For maintenance, please contact ABB or make sure that personnel performing maintenance are trained and certified by ABB. Depending on the application, load and environment, it is recommendable to perform one maintenance (cleaning (cleaning and inspection) during the transformer life. The figure of 15 years stated on the rating plate is provided as a guideline. For more details, see the appropriate User’s guide.
Pressure During drying, the tap- changers diverter switch housing should have no pressure difference to the transformer. This is obtained by opening the vapor phase (VP) valve in the bottom of the tapchanger diverter switch housing, see the Installation and commissioning guide for further information. During oil filling, up to 200 kPa pressure difference between the tap-changer diverter switch housing and the atmosphere is allowed. During service, max. 70 kPa pressure difference between the tap- changer diverter switch housing and the atmosphere is allowed. The pressure difference to the transformer tank during oil filling and testing is allowed to be max. 100 kPa. During service, it is recommended that the pressure difference be as low as possible and not more than 50 kPa and preferably higher in the transformer tank. For higher pressure differences, contact ABB. 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 technical description 1ZSC000562-AAD.
33
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Table 17. Weights for type VUCG. On-load tap changer type designation
VUCG.N
VUCG.T
VUCG.B
VUCG.E
S e l e c to r C
S el ec t or I I I
S e l e c to r F
B I L
C u rr e n t
Required oil in kg
-
-
-
-
-
-
-
-
-
-
W i t h o ut o i l
Total
Witho ut oi l
Total
Wi t h o u t o i l
Total
-
-
-
-
-
-
-
-
Table 18. Weights for type VUCL. On-load tap changer type designation
VUCL.N
VUCL.T
VUCL.B
VUCL.E
S e l e c to r I I I
S e l e c to r F
B BIIL
C u rr e n t
Required oil in kg
-
-
-
-
W i t h o ut o i l
Total
W it h ou t oil
Total
-
-
-
-
-
-
-
-
34
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Motor-drive mechanism Design For detailed design description, see separate Technical guides for motor-drive mechanisms types BUE or BUL, respectively. Installation The motor-drive mechanism is fitted to the outside of the transformer tank, and connected to the tap-changer by drive shafts and bevel gears. For the correct installation procedure, consult the appropriate Installation and commissioning guide. Maintenance The motor-drive mechanism should be visually inspected annually. For the correct inspection and maintenance procedures, consult the appropriate Maintenance guide.
Operating shafts The minimum and maximum lengths refer to mechanical design only. For L2 vertical shaft, see the dimension drawings on the following pages. Other shaft arrangements are available on request. For standard shaft arrangements, the max imum angle (totally in two directions) is 4°. For larger angles, order design is required. For single units (VUC..E, N) the gear box of the tap-changer might be mounted in the angle given in Fig. 44. The angle is given when ordering. Table 19. Operating shafts. L2 (mm)
L3 and L4 (mm)
Motordrive mechanism
Length
L1 (mm)
Min/max
/ /
/ B U UE E
/ /
–
/ /
BUL
-10°
190°
0°
a
Permitted range
— 44 Mounting angle, single unit.
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Fig. A
35
VUCG.N, E VUCL.N, E
L1
Fig. B
L1
Fig. C
VUCG.B VUCL.B
L3
L1
Fig. D
L1
L3
Fig. E
VUCG.T VUCL.T
L4
L3
Fig. F
L1
— 45 Designation of operating shafts.
L3
L4
L1
36
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
— Dimensions The design, technical data and dimensions are subject to alteration without notice. The dimension drawings in this guide show overall dimensions. For detailed information, see the dimension drawings in the website www.abb.com/electricalcomponents.
Dimensions, type VUCG Table 20. Diverter switch housings.
H1 (mm)
H1, short version (mm)
H3 2) (mm)
H3 2), short version (mm)
, ,
, ,
, ,
Impulse withstand For tap selector size voltage to earth (kV) C
III
F
Table 21. Tap selectors. For on-load tapchanger type
Max rated throughcurrent (A)
H2, H2, s ize ize C (mm (mm)) H2 H2,, si si z ze e IIII I (mm) (mm)
H2, H2, s ize ize F (mm) (mm)
VUCG.N
-
-
-
-
-
-
-
-
-
Single phase = Two phase =
Single phase = Two phase =
Single phase = Two phase =
Single phase = Two phase =
VUCG.E, VUCG.T
)
Single phase =
)
-
Two phase =
VUCG.B )
-
-
VUCG.B
1) Shielding rings are used only for insulation levels 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 max. 434 mm. 5) VUCG. VUCG.T T consists of three single-phase units. 6) VUCG.B consists of one single-phase and one two-phase unit arranged as shown in the dimension drawing for UCL.B.
37
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Space required for protective equipment.
C/L Tap selector
C/L Diverter switch
Section A – A Plus/Minus and Coarse/Fine switching
Section A – A Linear switching
— 46 Dimensions, type VUCG.E and VUCG.N with tap selector type C and cover mounting.
38
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Model for cover mounting
C/L Tap selector
Model for mounting on transformer’s active part
C/L Diverter switch
Section A - A Plus/Minus and Coarse/Fine switching
Section A - A Linear switching
— 47 Dimensions, type VUCG.E and VUCG.N with tap selector III and with tie-in resistor switch.
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
— 48 Dimensions, type VUCG.E with tap selector F and with tie -in resistor switch.
39
40
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Design for premounting on the active part of the transformer
— 49 Dimensions, type VUCG.B with tap selector F and with tie-in resistor switch.
41
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Dimensions, type VUCL The design, technical data and dimensions are subject to alteration without notice. The dimension drawings in this guide show overall dimensions. For detailed information, see the dimension drawings in the website www.abb.com/electricalcomponents. Table 22. Diverter switch housings. Impulse withstand voltage to earth (kV)
H1 (mm)
H3 2) (m m)
,
,
For mounting on active part
H+
H+
Table 23. Tap selectors. For tap-c tap-change hangerr type
Max rat rated ed through-c through-curr urrent ent (A)
H 2, size III (m m)
H2 , size F (m m)
VUCL.N
, ,
,
, , ,
, ,
Single - phase unit H =
Single - phase u nit H =
Two-ph wo-phas ase eu uni nitt H H =
Two-ph wo-phas ase eu uni nitt H H =
)
VUCL.E, T
VUCL.B )
1) Shielding rings are used only for insulation levels 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 max. 434 mm. 5) VUCL.T consist consists s of three single-phase units. 6) VUCL.B consists of one single-phase unit and one two-phase unit.
42
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Space required for protective equipment.
Section A – A Plus/Minus and Coarse/Fine switching
Section A – A Linear switching
— 50 Dimensions, type VUCL.E and VUCL.N with tap selector III and with tie-in resistor switch.
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
43
Design for premounting on the active part of the transformer
— 51 Dimensions, type VUCL.B with tap selector III and with t ie-in resistor switch.
44
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Space required for protective equipment.
Section A – A Plus/Minus and Coarse/Fine switching
— 52 Dimensions, type VUCL.E and VUCL.N with tap selector F and with tie-in resistor switch.
45
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Design for premounting on the active part of the transformer
— 53 Dimensions, type VUCL.B with tap selector F and with tie -in resistor switch.
46
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
77
49
1050 1274
1197
37
390 45 79 383
408 213
75
640
624
202
216 626 475
171
BUL2 — 54 Dimensions, motor-drive mechanisms.
BUE2
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
47
Oil conservator Although tap-changers of the vacuum type produce very small amount of gases, and far less particles than non-vacuum types, it is still recommended to use separate conservators in order to avoid possible impact on transformer DGA and particles coming into the transformer. The transformer manufacturer must provide a conservator for the tap-changer.
5. X corresponds to a height giving a max recommended pressure difference between the tap-changer diverter switch housing and the transformer tank of 50 kPa. 6. H corresponds to a height giving a max pressure press ure difference between the tap-changer diverter switch housing and the atmosphere of 70 kPa. For higher pressure difference, contact ABB for advice.
The diverter switch housing needs to be connected to an oil conservator. Consider the below as a guideline for the design of the tapchanger oil conservator.
7. The oil oil level for the tap-chang tap-changer er should be equal or below the oil level of the transformer. Temporary during service the value is allowed to be negative. 8. A vacuum proof conservator is needed if the tap-changer should be oil f illed under vacuum with the conservator mounted.
1. The breathing device should prevent moisture from getting into the tap-changer compartment and let gases 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. It is recommended to have the size of the conservator for vacuum type tap-changers an additional 15 l to the normal design rules of a tap-changer conservator. In order to have enough oil in the conservator to allow oil samples to be taken until the first maintenance stop stop without filling up with new oil. 4. It is recommended to install the oil sampling valve with piping accessible from ground level so that oil samples can be taken without disconnecting the transformer.
— 55 Oil conservator.
No special considerations is needed for transformer installations at high altitude. Note that separate oil conservators for the transformer and the tap-changer are recommended. Both oil and air side should be separated. For transformers with common conservator for both the transformer and the tap-changer a filter should be mounted in the pipe from the tap-changer to the conservator.
48
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
— Appendices: Single-phase diagrams The basic connection diagrams illustrate the different types of switching and the appropriate connections to the transformer windings. The diagrams illustrate the connections with the maximum number of turns in the transformer transform er 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 transformerr winding with the tap -changer in position 1. transforme Even positions when having change-over selector is made by blocking one position in the motor-drive.
Appendix 1: Single-phase diagrams for VU CG/C Li n e a r steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions: steps
Pl us/Min u s
Coarse/Fi ne
49
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Appendix 1: Single-phase diagrams for VU CG/C Li n e a r
Pl us/Min u s
Coarse/Fi ne
+
+
Number of tap positions:
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions: steps
Number of loops:
50
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Appendix 1: Single-phase diagrams for VU CG/C Li n e a r
Pl us/Min u s
Coarse/Fi ne
+
+
steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions:
51
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Appendix 1: Single-phase diagrams for VU CG/C Li n e a r
Pl us/Min u s
Coarse/Fi ne
+
+
steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions steps
Number of loops: Number of tap positions:
52
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Appendix 1: Single-phase diagrams for VU CG/C Li n e a r
Pl us/Min u s
Coarse/Fi ne
+
+
+
+
steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions:
53
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Appendix 1: Single-phase diagrams for VU CG/C Li n e a r
Pl us/Min u s
Coarse/Fi ne
+
+
+
+
steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions:
steps
Number of loops: Number of tap positions:
54
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Appendix 2: Single-phase diagrams for VUCG/III and VUCL/III Li n e a r steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions:
Pl us/Min u s
Coarse/Fi ne
55
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Appendix 2: Single-phase diagrams for VUCG/III and VUCL/III Li n e a r
Pl us/Min u s
Coarse/Fi ne
+
+
steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions:
56
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Appendix 2: Single-phase diagrams for VUCG/III and VUCL/III Li n e a r
Pl us/Min u s
Coarse/Fi ne
+
+
steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions:
57
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Appendix 2: Single-phase diagrams for VUCG/III and VUCL/III Li n e a r
Pl us/Min u s
Coarse/Fi ne
+
+
steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions:
58
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Appendix 2: Single-phase diagrams for VUCG/III and VUCL/III Li n e a r
Pl us/Min u s
Coarse/Fi ne
+
+
+
steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions: steps
Number of loops:
Number of tap positions:
steps
Number of loops:
Number of tap positions:
59
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Appendix 2: Single-phase diagrams for VUCG/III and VUCL/III Li n e a r
Pl us/Min u s
Coarse/Fi ne
+
+
+
+
steps
Number of loops:
Number of tap positions:
steps
Number of loops:
Number of tap positions:
steps
Number of loops:
Number of tap positions:
steps
Number of loops:
Number of tap positions:
60
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Appendix 2: Single-phase diagrams for VUCG/III and VUCL/III Li n e a r
Pl us/Min u s
Coarse/Fi ne
+
steps
Number of loops:
Number of tap positions:
61
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Appendix 3: Single-phase diagram s for VUCG/F and VUCL/F Li n e a r steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions:
Pl us/Min u s
Coarse/Fi ne
62
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Appendix 3: Single-phase diagram s for VUCG/F and VUCL/F Li n e a r
Plu s/Min u s
C o a r se/ F i n e
+
+
steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions:
63
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Appendix 3: Single-phase diagram s for VUCG/F and VUCL/F Li n e a r
Pl us/Min u s
Coarse/Fi ne
+
+
steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions: steps
Number of loops:
Number of tap positions:
64
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Appendix 3: Single-phase diagram s for VUCG/F and VUCL/F Li n e a r
Pl us/Min u s
Coarse/Fi ne
+
+
+
steps
Number of loops: Number of tap positions: steps
Number of loops: Number of tap positions: steps
Number of loops:
Number of tap positions:
steps
Number of loops:
Number of tap positions:
65
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Appendix 3: Single-phase diagram s for VUCG/F and VUCL/F Li n e a r
Pl us/Min u s
Coarse/Fi ne
+
+
+
+
steps
Number of loops:
Number of tap positions:
steps
Number of loops:
Number of tap positions:
steps
Number of loops:
Number of tap positions:
steps
Number of loops:
Number of tap positions:
66
ON-LOAD TAP-CHANGERS TYPE VUC TECHNICAL GUIDE
Appendix 3: Single-phase diagram s for VUCG/F and VUCL/F Li n e a r
Pl us/Min u s
Coarse/Fi ne
+
+
+
steps
Number of loops:
Number of tap positions:
steps
Number of loops:
Number of tap positions:
steps
Number of loops:
Number of tap positions:
— ABB AB, Components SE-771 80 Ludvika Sweden E-mail:
[email protected] www.abb.com/transformer www.abb.com/ transformercomponents components
5 1 4 0 8 1 0 2 , 3 . v e R , n e X A A 2 6 5 0 0
