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.

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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.

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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

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13.4 Notice..............................................................................................................................................53
14. Appendix .........................................................................................................................54

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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.

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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.

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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.

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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

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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

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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.