Huaming CVIII 350Y User manual

Operating Instructions
HM 0.460.001-02.05/2021
CV & SV
On-Load Tap-changer
IMPORTANT:
Please read this manual carefully
before using the tap-changer and
save it for reference.

HM0.460.001
2
Thank you for choosing Huaming products.
Before using, please read this instruction carefully. The product may have been modified
since this document was published. We reserve the right to change the technical data, design
and scope of supply without warning in advance. Generally, information provided with
individual quotations and orders is binding. Huaming has no liability for any damage due to
incorrect interpretation of this document.
Keep this manual at hand for future use and in case of any question, please contact Huaming.
Prior to using the on-load tap-changer, make sure to pay attention to the following items:
1.Tap-changer and motor drive unit must be connected on the same position.
2. The tap-changer must not be operated after being dried without oil. If the operation is inevitable, the
rotating parts and contacting parts of the tap-changer must be lubricated with transformer oil.
3. After the drive shafts are installed on transformer, motion angle must be calibrated (See operating
instruction for the details).
4. The drive shaft must be exactly fit for operation, not too short in order to prevent from falling off or
too long to be damaged due to heat expansion.
5. The worm gear reducers on the top-cover of the OLTC can be adjusted by loosening the bolts of the
fixing ring according to user installation required. Please be sure to secure the bolts upon the
completion of adjustment.

HM0.460.001
3
TABLE OF CONTESTS
1.Foreword...............................................................................................................................5
1.1 Safety.................................................................................................................................................5
1.2 Notation and conventions ..................................................................................................................5
1.3 Safety precautions..............................................................................................................................6
2. General ................................................................................................................................7
3. Technical data......................................................................................................................9
3.1 Table of technical data.......................................................................................................................9
3.2 Operation conditions........................................................................................................................10
4. Type designation................................................................................................................11
4.1 Type designation ..............................................................................................................................11
4.2 Internal insulation level....................................................................................................................12
4.3 Tap selector wiring diagram ............................................................................................................13
5. Packing, transportation & storage......................................................................................14
5.1 Supplied components .......................................................................................................................14
5.2 Transportation & acceptance ...........................................................................................................14
5.3 Storage .............................................................................................................................................16
6. Mounting of tap-changer on the transformer......................................................................17
6.1 Transformer mounting flange for tap-changer installation...............................................................17
6.2 Mounting of tap-changer on standard type transformer ...................................................................18
6.3 Mounting of tap-changer on bell-type transformer...........................................................................20
6.4 Connection between tap of voltage regulating winding and terminal of tap-changer......................27
7. Transformer ratio test and transformer DC resistance measurement..................................28
7.1 Transformer ratio test........................................................................................................................28
7.2 Transformer DC resistance measurement.........................................................................................29
8. Drying process and oil filling.............................................................................................30
8.1 Drying process.................................................................................................................................30
8.2 Oil filling...........................................................................................................................................34
9. Installation of tap-changer protection device and transmission device components...........35
9.1 Installation of gas relay.....................................................................................................................35
9.2 Use of pressure relief device.............................................................................................................35
9.3 Installation of motor drive unit.........................................................................................................35
9.4 Installation of bevel gear box............................................................................................................35
9.5 Installation of horizontal and vertical drive shafts............................................................................37
9.6 Installation of driving shaft shield cover ..........................................................................................39
9.7 Installation of tap-changer group......................................................................................................41
9.8 Tap position calibration of tap-changer transmission system...........................................................43
10. Tap-changer Factory test and test preparation..................................................................44
10.1Test preparation ...............................................................................................................................44
10.2Test in transformer factory ..............................................................................................................46
11. Transformer transportation and put into operation on site................................................48
11.1 Remove the MDU for transportation..............................................................................................48
11.2 Oil filling and transportation without oil conservator.....................................................................48
11.3 Transportation without oil...............................................................................................................48
11.4 Putting transformer into operation on site ......................................................................................49
12. Tap-changer operation monitoring and maintenance .......................................................50
13. Maintenance.....................................................................................................................51
13.1 Inspection........................................................................................................................................52
13.2 Maintenance interval.......................................................................................................................52
13.3 Recommendation of oil filter installation.......................................................................................53

HM0.460.001
4
13.4 Notice..............................................................................................................................................53
14. Appendix .........................................................................................................................54

HM0.460.001
5
1.Foreword
This instruction manual is a comprehensive description of product transportation, installation,
commissioning, test and maintenance. It is intended for trained and qualified staff related to
transformer production, testing and quality assurance, and has reference value for transformer
design and operation personnel.
1.1 Safety
Safety instructions are explained in this manual. They must be observed and followed to avoid
relevant dangers.
Personal safety equipment must be worn during work to prevent potential risks.
Protective clothing for protecting personnel from hazards
in the work environment.
Safety shoes for protecting personnel from falling sharp
objects and slippery surfaces.
Goggles for protecting eyes and facial area from impact,
dust, liquid splash and high heat hazards.
Hard hat for protecting head from injury.
Hearing protection for protecting hearing from damage.
Protective gloves for protecting hands from mechanical,
chemical, and electrical hazards.
Table 1 Personal safety equipment list
1.2 Notation and conventions
DANGER!
The yellow triangle warning sign means life and health may be at risk if
neglecting the instruction. Neglecting this warning can lead to serious or fatal
injuries.
CAUTION!
The orange round warning symbol means products or device may be
damaged if the instruction is not observed. Neglecting this warning can lead
to product’s or operator’s damages and injuries.

HM0.460.001
6
1.3 Safety precautions
Precaution
Action
Electric shock
Always unplug a device before inspection. Stay away from high-voltage
equipment and wear protective clothing.
Transformer oil
Collect used transformer oil in dedicated drums. Keep it away from
flames or sparks. Do not touch it which may cause damages to health.
Fire
In case of fire, extinguish it with powder, foam or carbon dioxide. Do
not use water.
Waste
Wastes are dangerous to the environment or human health. Clean them
up in time and use different methods according to the wastes’ categories.
Table 2 Safety precaution
NOTE!
The blue note symbol indicates important information that must be noted.

HM0.460.001
7
2. General
CV/SV on-load tap-changer, used to regulate voltages, is suitable for power or industrial
transformers with rated voltages of up to 110kV, a maximum rated current of three-phase 500A,
single-phase 700A, and a frequency of 50Hz or 60Hz.
CV/SV is selector switch type OLTC which combines the duties of a diverter switch and a tap
selector in one compartment.
They are installed on the transformer tank cover via the tap-changer head flange, and is
connected to the CMA7 or SHM-D motor drive unit through the worm gear reducer, horizontal
drive shaft, bevel gear box, and vertical drive shaft, so as to achieve the purpose of tap change.
NOTE!
Special design is available. Please contact Huaming for further information.

HM0.460.001
8
Figure 1 Overview of tap-changer
Table 3 List of tap-changer components
1. Pipe bend
2. Upper gear unit
3. Horizontal drive shaft
4. Bevel gearbox
5. Vertical drive shaft
6. Motor drive unit
7. Oil compartment

HM0.460.001
9
3. Technical data
CV/SV tap-changer complies with IEC 60214-1: 2014 standard.
3.1 Table of technical data
Description
CVIII 350Y
CVIII 350D
CVI 350
SVIII 500Y
SVIII 500D
CVI 700
Max. rated through current (A)
350
350
350
500
500
700
Rated frequency (Hz)
50 or 60
Connection
3-phase Y-connection for neutral point only
3-phase D-connection for any connection except neutral point
Single-phase for any selectable winding connection
Max. rated step
voltage (V)
10 contacts
1500
1500
1500
12 contacts
1400
1400
1400
14 contacts
1000
--
1000
Rated step capacity
(kVA)
10 contacts
525
400-525*
660
12 contacts
420
325-420*
520
14 contacts
350
--
450
Short-circuit
current test (kA)
Thermal (3s)
5
7
10
Dynamic (peak)
12.5
17.5
25
Max. operating positions
See Figure 4
Insulation to
ground
The highest voltage for
equipment (kV)
40.5
72.5
Rated separate source AC withstand
voltage (kV/50Hz, 1min)
85
140
Rated lightning impulse
withstand voltage (kV,1.2/50μs)
225
350
Tap selector
Categorized into B, C, D & DE four sizes
Mechanical life
Not less than 800,000 operations
Electrical life
Not less than 200,000 operations
Oil compartment
of diverter switch
Service pressure
0.03MPa
Leakage test
No leakage under 0.1 MPa for 24 hours
Over pressure protection
Rupture disc bursts at 300 ±20% KPa
Protective relay
Set oil flow speed at 1.0m/s ±10%
Motor drive unit
CMA7 or SHM-D
*Note: The max. through current should decrease to 350A and 300A when the switching capacities are 525 kVA and 420 kVA.
Table 4 CV/SV technical data

HM0.460.001
10
3.2 Operation conditions
1). The operating temperature of the tap-changer in oil is ≥-25℃ and ≤105℃.
2). The storage environment temperature of the tap-changer is ≥-25℃and ≤40℃, and the humidity
should be not higher than 85%. If beyond this standard, please mark your requirements before ordering.
The tap-changer material and accessories will be specially processed to meet the special requirements of
the environment.
3). After being mounted to the transformer, the non-perpendicular degree between the tap-changer and the
ground should be less than 2°.
4). No sever dust and other explosive or corrosive gases on the installation site.
CAUTION!
Do not store the tap-changer or motor drive unit in a place with high humidity (≥85%). This
will cause condensation.
NOTE!
Special design is available to meet particular environment conditions. Please contact
Huaming for further information.

HM0.460.001
11
4. Type designation
4.1 Type designation
CV/SV tap-changers have a variety of specifications due to different combinations of the number of
phases, the maximum rated through current, the highest voltage of the equipment, the insulation class of
the selector and the connection mode. Therefore, the above-mentioned performance parameters should be
clearly reflected in the model of the tap-changer, and the detailed description of each code is shown in
Figure 2.
Figure 2 CM2 model designation
4.1.1 Basic connection
According to the transformer voltage regulation and winding connection mode, the tap selector has a
variety of different specifications. It is composed of the number of tap selector pitch, the number of
operating positions and the form of the changeover selector. The designation of the tap selector model is
shown in Figure 3.
Figure 3 Tap selector basic connection
CV III -350 Y/ 40.5 12233W
Type
Number of phases
Max. rated through current
Connection mode: Y or D
OLTC highest voltage
Tap selector basic connection diagram
10 19 3 W
Tap selector pitch (divided into 10, 12 and 14)
Operating positions (depending on w or w/o
change-over selector. Max. 27)
No. of mid positions (0, 1 or 3)
Change-over selector (0: linear; W: reversing;
G: coarse & fine)

HM0.460.001
12
For example:
1). Linear regulation: It is represented by 5 digits. For example, 14140 means that the contact position of
each phase is 14, the number of working positions is 14, and the number of intermediate positions is 0.
2). Reversing regulation: Add a letter W after 5 digits, such as 14131W, which means that the contact
position of each phase is 14, the number of working positions is 13. The number of intermediate positions
is reversing adjustment.
3). Coarse and fine regulation: 5 digits followed by a letter G, such as 14131G, indicating the contact
position of each phase 14, the number of working positions is 13. The number of intermediate positions is
coarse and fine adjustment.
4.2 Internal insulation level
The tap-changer internal insulation level is shown in Table 5.
unit(kV)
Insulation distance
Tolerating voltage
Type of tap-changer
CVIII350Y
CVIII350D
CVI350
SVIII500Y
SVIII500D
CVI700
a
10 contacts
1.2kV/50μs
200
kV50Hz 1min
50
12 contacts
1.2kV/50μs
180
kV50Hz 1min
50
14 contacts
1.2kV/50μs
170
kV50Hz 1min
50
b
40.5kV
1.2kV/50μs
200
225
--
kV50Hz 1min
70
85
--
72.5kV
1.2kV/50μs
200
350
--
kV50Hz 1min
70
140
--
c
40.5kV
1.2kV/50μs
350
350
--
kV50Hz 1min
140
140
--
72.5kV
1.2kV/50μs
350
350
--
kV50Hz 1min
140
140
--
d
1.2kV/50μs
200
kV50Hz 1min
53
f
40.5kV
1.2kV/50μs
225
kV50Hz 1min
85
72.5kV
1.2kV/50μs
350
kV50Hz 1min
140
Table 5 Insulation level of Tap selector

HM0.460.001
13
4.3 Tap selector wiring diagram
The different transformer voltage winding tapping methods correspond to different specifications of tap
selector’s basic wiring diagrams. Figure 4 shows the common basic wiring diagrams. Special designs can
be made to meet customers’ requirements.
Figure 4 Basic connection diagram of Tap selector

HM0.460.001
14
5. Packing, transportation & storage
5.1 Supplied components
The complete set of tap-changer contains below parts
(Figure 5):
•Tap-changer
•Motor drive unit (MDU), controller and connecting cables, transmission shafts, couplings, bevel
gear boxes and other transmission accessories
•Protection relay and accessories
•Special tools and accessories for tap-changer assembly
•Customer-required special accessories if any.
Please refer to the corresponding packing list delivered with the tap-changer for exact supplied
components.
Figure 5 Set of tap-changer
5.2 Transportation & acceptance
5.2.1 Transportation
•Packings is suitable for all common kinds of transportations. The boxes of tap selector and MDU are
allowed to be appropriately stacked during storage, and the load-bearing capacity of the box’s top surface
shall not exceed 500kg/m2.
•Boxes should be placed reasonably according to the position of the gravity center. When lifting it up,
the markings on the box must be observed (Figure 6).
Figure 6 Example of markings on the box
This side up
Fragile
Keep dry

HM0.460.001
15
5.2.2 Goods receiving
Each batch of delivered goods must be checked by the consignee before accepted (signing acceptance
confirmation). Following items must be checked by the consignee carefully:
•When receiving the goods, check the quantity of components received according to the packing
list.
•Check whether the packing is intact. If it’s found to be damaged (if possible, take pictures of the
box and damaged goods) or the information of the goods does not match the packing list,
consignee should refuse to sign for acceptance, and immediately report the problem to the shipping
company and Huaming.
•The above steps are also applicable to corrosion of the goods due to moisture immersion (rain, snow,
condensed water). The components must be stored in a dry place before installation.
•The on-load tap-changer must be stored in a sealed packing box and opened before installation only.
DANGER!
When lifting and storing the boxes, people are not allowed to stand under or
near the boxes in case the boxes drop. All boxes must be stored properly and
safely.
CAUTION!
Choose appropriate forklift and crane according to the dimension and gross
weight of the boxes.
NOTE!
When receiving the goods, please check carefully the packing and the supplied
components according to the packing list. In case anything is broken or missing,
please contact Huaming in time.
NOTE!
The transportation and lifting of the box must be operated by professionals.
The carrying capacity of transportation vehicles and cranes should be more than
1000kg.
CAUTION!
The packing box should be firmly fixed during transportation and lifting,
and be handled with care to avoid possible damage to the product due to
vibration, impact, falling, tipping, bumping, shaking, etc.

HM0.460.001
16
5.2.1 Acceptance
Unpack the box and look for damage during transportation.
⚫Transport the box to the installation site.
⚫Check the equipment and its accessories according to the packing list.
5.3 Storage
When the goods are stored continuously for more than 1 year, the equipment should be inspected
thoroughly before installation.
Specially packed goods with sealed packing can be stored outdoors if they meet the following conditions.
•The storage environment temperature should not be ≥-25℃ and ≤40℃.
•The tap-changer must not be stored in an environment with flammable, explosive and corrosive gases.
•It must be protected from moisture, dust, rodents and ants.
•Regularly check whether the stored equipment is abnormal
•If the tap-changer is stored for a long time, the desiccant must be replaced regularly, and re-packed with
sealed packing.
CAUTION!
If the box drops or is severely impacted, the possibility of damages must
be considered. Comprehensive inspection of the product should be
carried out, and if necessary, inspection(repair) shall be done by the
Huaming’s professional and technical personnel.
CAUTION!
During unpacking and inspection, avoid damaging the original package.
NOTE!
Ifthereceivedgoodsanditsaccessoriesdonotmatchthelist,contactHuamingintime.
CAUTION!
After long-term storage, the tap-changer and its accessories must be
carefully inspected before installation.

HM0.460.001
17
6. Mounting of tap-changer on the transformer
6.1 Transformer mounting flange for tap-changer installation
A mounting flange is required to fix the tap-changer head on the transformer cover. The structure of the
flange should be designed according to the shape of the tap-changer head’s sealing surface (Figure 7).
Double-thread screw (M12, maximum length=45mm) should be accurately positioned.
Figure 7 Transformer mounting flange
Transformer tank cover
mounting flange
Transformer
tank cover

HM0.460.001
18
6.2 Mounting of tap-changer on standard type transformer
1) Clean the bottom sealing face of the tap-changer head flange as well as the surface of transformer
mounting flange, and place a sealing gasket on it (Figure 8).
2) Lift the assembled tap-changer to be above the transformer’s mounting flange. Carefully
place it into the transformer tank through the mounting hole on the transformer cover (Figure
9).
Figure 8 Sealing face
Figure 9 Mounting hole
Clean the sealing face
Sealing ring
Head flange
Transformer cover
Sealing ring
Mounting
flange
97

HM0.460.001
19
3) Check whether the tap-changer head’s mounting position and angle meet the design requirements. If
yes, fix the tap-changer head flange to the transformer’s mounting flange, and fasten 24 pieces of nuts
with a torque of 100 to 110 N.m.
CAUTION!
Make sure not to damage the tap-changer’s wiring terminal and tie-in resistors, if any.

HM0.460.001
20
6.3 Mounting of tap-changer on bell-type transformer
6.3.1 Disassembly of tap-changer head cover
1) Make sure the tap-changer is at the calibration position.
2) Unscrew the 24 pieces of M10 bolts on the tap-changer head cover (with spring washer, 17mm
wrench).
3) Remove the tap-changer head cover (Figure 10).
During disassembly and other operations, avoid damaging the head cover and the sealing surface (O-ring)
(Figure 11).
Figure 10 Tap-changer head cover
Figure 11 Tap-changer sealing ring
Sealing ring