Power IT Transformers and Reactors

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Instruction and Operation Manual

90/100 MVA, 295/11 kV, 3-Phase, 50 Hz Power Transformer

Serial No. 512040

for

INCO Larona Project

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Part 2 Equipment and Accessories Information

Part 3 Transformer Drawings and Photographs

Part 4 Control Circuit and Control Equipment

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Part 1: Installation, Operation and Maintenance

90/100 MVA, 150/11 kV, 3-Phase, 50 Hz Transformer

for

INCO Larona Project

Contract No. PO.No.3162022214/Rev.4

ABB Job Number PPTR12E040 / TH-50912040

ABB Serial Number 512040

Year of Manufacture 2014

Plant

Number-Prepared 05 March 2014

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TABLE OF CONTENTS

1 TRANSFORMER DATA ... 1-1 1.1 MANUFACTURER 1-1 1.2 GENERAL 1-1 1.3 MECHANICALDETAILS 1-1 1.4 ELECTRICALCHARACTERISTICS 1-2 2 TANK ... 2-3 2.1 COREEARTHING 2-3 2.2 VALVES 2-3 2.3 GASKETS 2-4

2.4 TIGHTENING ANDRE-TIGHTENINGBOLTEDJOINTS 2-7 2.5 EXPANSIONCOUPLINGS 2-8

2.6 TRANSFORMERMOUNTINGSYSTEM 2-8

3 CONSERVATORS ... 3-9

3.1 DESIGN OFCONSERVATOR 3-9

3.2 OILCONSERVATOR W ITHAIR CELL 3-9 3.3 OILCONSERVATOR WITHOUTAIRCELL 3-11 3.4 ONLOADTAPCHANGERCONSERVATOR 3-11

4 PAINT SYSTEM ... 4-12

4.1 PREPARATIONBEFOREPAINTING 4-12

5 SHIPPING OF TRANSFORMERS ... 5-19

5.1 GENERAL 5-19

5.2 SHIPPINGINFORMATION 5-19

5.3 TRANSPORTATION 5-19

5.4 SUCCESSFULSHIPMENTVERIFICATION 5-20

6 OFF LOADING AT SITE ... 6-23

6.1 INSPECTIONBEFOREOFF-LOADING 6-23

6.2 OFF-LOADING THETRANSFORMER 6-27

7 MONITORING DRY-GAS FILLED TRANSFORMERS DURING SHIPMENT AND

STORAGE ... 7-31

7.1 WITHGASCYLINDERS 7-31

7.2 WITHOUT GAS CYLINDERS 7-33

8 STORAGE ON SITE BEFORE ASSEMBLY ... 8-35

8.1 GENERAL 8-35

8.2 SEPARATESTORAGE OFUN-MOUNTED ACCESSORIES 8-35 8.3 STORAGE OFMAINUNIT INOIL(FOR UNITS SHIPPED IN OIL) 8-36

8.4 STORAGE OFMAINUNIT INDRYGAS(FOR UNITS SHIPPED IN DRY GAS) 8-36

9 RECEIVING AND HANDLING TRANSFORMER OIL ON SITE ... 9-37

9.1 GENERAL 9-37

9.2 TYPES OFOIL 9-37

9.3 INHIBITEDOILS 9-37

9.4 SUPPLIERCERTIFICATE 9-38 9.5 SAMPLING ONSITE 9-38 9.6 TESTING OF CHARACTERISTICS OF OIL SAMPLES (FOR NON-CERTIFIED

OIL) 9-38

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Instruction and Operation Manual INCO Larona Project Power Transformer Serial No. 512040

ABB LIMITED – Power Transformer Division, Thailand Revision: Original

iv

10 TRANSFORMER ASSEMBLY INSTRUCTIONS ... 10-41

10.1 GENERAL 10-41

10.2 SAFETYNOTATIONS 10-41

10.3 PREPARATION 10-41

10.4 CHECKING FORLEAKS ANDDRYNESSAFTERSHIPMENT 10-42 10.5 DEWPOINTMEASUREMENT 10-42 10.6 PREPARATION FOROILFILLING 10-43

10.7 CHECKING FORLEAKSDURINGASSEMBLY 10-43

10.8 EXTERNALASSEMBLY 10-43 10.9 INTERNALASSEMBLY 10-45

10.10 CLOSING THETRANSFORMER 10-47

11 VACUUM OIL FILLING ON SITE ... 11-49

11.1 GENERAL 11-49

11.2 NECESSARYEQUIPMENT 11-49 11.3 VACUUMTREATMENT WITHFINALLEAKTEST 11-49 11.4 PROCESSING THEOILBEFOREFILLING 11-51

11.5 FILLINGPROCEDURE FOR THEMAINTANK 11-52 11.6 FILLINGPROCEDURE FORON-LOADTAPCHANGER 11-53 11.7 FILLINGPROCEDURE FORSEPARATECOOLERS 11-53

11.8 CIRCULATINGOIL IN THEMAINTRANSFORMERTANK 11-53

11.9 OILCIRCULATIONPROCEDURE 11-54 11.10 IMPREGNATIONTIMEBEFOREENERGIZING 11-54 11.11 ADDITIONALDRYINGPROCEDURE ONSITE 11-54 11.12 RE-FILLINGAFTERINTERRUPTEDPROCEDURES 11-54

11.13 OILLEAKPRESSURETEST 11-55

12 TRANSFORMER TESTING ON SITE AFTER ASSEMBLY ... 12-57

12.1 GENERAL 12-57

12.2 INSPECTION ANDTESTRECORD 12-57

12.3 RATIOTEST 12-57

12.4 WINDINGRESISTANCETEST(THIS TEST IS OPTIONAL) 12-57 12.5 CHECK OFVECTORGROUP(THIS TEST IS OPTIONAL) 12-58

12.6 INSULATIONRESISTANCETEST 12-58

12.7 CAPACITANCE AND POWER FACTOR OR DISSIPATION FACTOR

MEASUREMENT 12-59

12.8 CHECK OFTANKGROUNDCIRCUITCONTINUITY 12-59 12.9 POLARITYCHECK OFCURRENTTRANSFORMERS 12-59

12.10 CHECK OFTHERMOMETERS ANDTHERMOSTATS 12-59

12.11 OILTESTS 12-59

12.12 OPERATIONALTEST OFSUPERVISORYEQUIPMENT 12-60 12.13 OPERATIONALTEST OFOTHEREQUIPMENT 12-60

12.14 FINALAIRBLEEDING 12-61

13 ENERGIZATION ... 13-63

13.1 PREPARATION FORENERGISATION 13-63

13.2 ENERGISATION 13-63

13.3 SHUTDOWN ANDRE-ENERGISATION OFTRANSFORMERS WITHINERTAIRE

ORSEALEDAIREOILPRESERVATIONSYSTEM. 13-64 13.4 SHUT DOWN AND RE-ENERGISATION OF TRANSFORMERS WITH COPS

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14 MAINTENANCE ... 14-65

14.1 GENERAL 14-65

14.2 MONTHLYMAINTENANCE 14-65 14.3 FOURMONTHLYMAINTENANCE 14-66

14.4 YEARLYMAINTENANCE 14-67 14.5 LONG-TERMMAINTENANCE 14-70 14.6 RADIATORREMOVAL ANDREPAIR 14-70

14.7 PUMPREMOVALANDREPLACEMENT 14-71

14.8 PARTIALOILDRAINING ANDFILLING 14-72 14.9 REMOVAL OFWELDEDTANKCOVER 14-74

14.10 REPLACINGWELDEDCOVERGASKET 14-75

14.11 RELOCATION OFTRANSFORMER 14-75

15 ENVIRONMENTAL IMPACT ... 15-79

15.1 ENVIRONMENTALIMPACT OFOPERATION 15-79 15.2 DISPOSALPRECAUTIONS 15-79 15.3 SAFETYCONSIDERATIONS 15-80

16 USEFUL CONVERSION VALUES AND FORMULAE ... 16-83

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1

TRANSFORMER DATA

1.1 Manufacturer

ABB LIMITED

Power Transformer Business

322 Moo 4, Bangpoo Industrial Estate Sukhumvit Road, Praeksa

Amphur Muang

Samutprakarn, 10280, THAILAND

1.2 General

The transformer referred to in this manual is an oil-immersed core-form type transformer with the following characteristics:

Type of Transformer 3-Phase

Type of Cooling ONAN, ONAN

Power Rating 90/100 MVA

Transformation Ratio 150 (+3, -1 x 2.5%)/11 kV Transformer General Arrangement

Customer Drawing Outline Drawing

Refer to the following drawing : XTH 4605 00-EUH

XTH 4605 01-EUH

1.3 Mechanical Details

Terminations and LV Arrangement Terminal Pad and Connecting Device Detail of LV Busduct Flange

Refer to the following drawing: XTH 4605 04-EUH

XTH 4605 09-EWP

Radiators Twenty-Seven (27)

Fans N/A

Pumps N/A

Conservator Vacuumproof, fitted with air cell

Approximate Masses Refer to the following drawing:

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Chapter 1-2

1.4 Electrical Characteristics

1.4.1 Performance

Frequency 50 Hz

Phases 3

Continuous Rating ONAN 90 MVA

ONAN 100 MVA

High Voltage 150 kV

Low Voltage 11 kV

Vector Group YNd1

Standard IEC 60076

1.4.2 Insulation Levels

Lightning Impulse Power Frequency

HV 650 275 kV

LV 250 70 kV

HVN 250 70 kV

1.4.3 Auxiliary Power Supply

Cooling Fans 380/220 VAC, 3-Phase, 50 Hz

OLTC Motor Drive N/A

Control Circuits 110 VDC.

For connection diagram and additional information, refer to the Rating Plate drawing XTH 4608 01-EUH.

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2

TANK

2.1 Core Earthing

The ground-connection terminals for the transformer active part are located in a box on the tank cover, refer Outline Drawing XTH 4605 01-EUH.

Links can be removed for test purposes, see Figure 2.1.

Figure 2.1 Core earthing terminal block – topside

CC = core clamps, core frame structure which is isolated from tank

CL = core laminations, limbs and yokes which are isolated from core frame G = ground, connected to underside of tank cover.

Typical insulation values between core laminations and core frame, and core frame and tank, when links are removed are 1 to 10 GW when measured with 2.5 kV insulation tester.

2.2 Valves

2.2.1 Valve Schedule

Refer to Outline Drawing XTH 4605 01-EUH for quantity, position and description of valves fitted to the transformer. Refer to Valves on Transformer drawing XTH 4605 07-EUH for details.

2.2.2 Gate Valves

Small gate valves up to DN 80 are bronze; larger gate valves over DN 80 are cast iron with bronze wedge and are supplied with rising spindle shafts.

The shaft gland consists of an external packed gland, which allows gland adjustment when required. This gland is specially packed for use on transformer oil and this must be stated when ordering replacement valves.

2.2.3 Butterfly Type Isolating Valves

The radiator-isolating valve is of the butterfly type construction.

The seal at the butterfly is obtained without the use of gaskets that could be damaged by use.

Ground CC

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Chapter 2-4 The admitted oil leakage rate is less than 500 cm3/hour.

Gaskets seats on both sides of the flange are designed for ‘O’-ring type gaskets. The drive shaft seal is obtained by ‘O’-ring type gasket, which can be quickly replaced.

2.3 Gaskets

2.3.1 Rubber-Cork Gaskets

When rubber-cork gaskets are used, the standard material is cork type A70; a synthetic rubber and cork material having the following properties:

Shore ‘A’ Hardness 60 – 80

Specific Gravity 0.80 – 0.85 g/cm3

Compressibility at 2.8 MPa 35 – 50 %

Tensile Strength, minimum 1,200 kPa

Recovery, minimum 80 %

Volume Change After Immersion in Oil at 100°C for 24 hours - 5 to +10 %

A typical bolted joint employing rubber-cork gasket is shown in Figure 2.3.2; recommended fastening torque for bolted joints are shown in Table 2.3.2.

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Table 2.3.2 Fastening torque for gasket joints

Stud or Bolt Size Torque (Nm)

M12 30

M16 75

M20 145

M24 250

M30 500

2.3.2 ‘O’ Ring Gaskets

The sealing system normally used for bushing flanges, OLTC support flanges, hand holes, covers, plugs, etc. is an ‘O’-ring gasket as shown in Figure 2.3.3/1.

The gaskets have a circular cross-section and are made of oil and heat-resistant synthetic nitrile rubber. For small gaskets, ‘O’-rings having a cross-sectional diameter up to 8.4mm are used, for larger gaskets round rubber cords having cross-sectional diameter up to 19mm are used.

The groove is normally milled or turned, but for large flanges the groove is created by means of steel bars welded on top of the flange. The width of the groove is slightly smaller than the cross-sectional diameter of the gasket. At the assembly stage, the gasket is compressed to fill the groove.

Opened sealing joints may be sealed again using the same gasket provided that it has not been damaged. If the gasket has hardened or small cracks on the surface are evident, it is recommended to replace it with a new gasket.

Figure 2.3.3/1 Typical ‘O’-Ring Gasket Joint

When handling and lifting flanges, covers, etc. with gasket grooves; take care when using tools and lifting devices to avoid damaging or deforming grooves.

Before assembling sealing joints, check that grooves and contact-surfaces on the joining faces are free from foreign particles and that the painted surface is free from thick coatings, runs and drips. When assembling the rubber cord in the groove, the cord length shall be continuous. The gasket is given a small surplus length to compensate for shrinkage, see Table 2.3.3.

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Chapter 2-6

Table 2.3.3 Amount of surplus length for rubber-cord gaskets

Rubber Cord, mm Length Range, m Surplus Length, mm

Æ 8.00 0.5 – 1.0 10 1.0 – 1.5 15 Æ 12.0 1.5 – 2.0 20 2.0 and up 25 Æ 19.0 up to 5 20 5 – 10 30 10 – 15 40 15 – 20 50 20 and up 60

The gasket is pressed down into the groove without stretching or slackening. The joint is placed according to Figure 2.3.3/2 and is then glued. The cut end should be completely perpendicular to the long axis of the gasket and it is recommended to use a sharp knife in a special fixture. The ends of the cord are pressed against each other and pushed down in the groove. The rest of the gasket is distributed evenly around the groove and fixed intermittently along its length by pressing down into the groove. When the entire gasket is evenly distributed, it is pressed down in the groove along the entire length. Make sure that the cut ends are pressed together correctly without misplacement or gaps.

Gasket in groove with a sharp corner

Figure 2.3.3/2 Positioning of joint in rubber cord

To prevent the gasket from falling out of the groove on vertical surfaces, the gasket may be spot-glued to the bottom of the groove with fast setting glue.

In order to get a correctly sealing joint it is necessary to tighten the bolts evenly. This is best achieved by alternate tightening of opposing bolts. A torque wrench or automatically controlled tool should be used to tighten the bolts or nuts. Refer to Tables 2.4/1, 2 and 3 for torque settings. Rubber gaskets in grooves need not normally be re-tightened.

2.3.3 Tank Cover Gasket

If the transformer is fitted with a welded cover, it requires a special gasket. Details of how to replace this gasket are contained in Chapter 14.10.

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2.4 Tightening and Re-Tightening Bolted Joints

The following tightening torque values are applicable for joints between details of steel. They shall also be applied for bolted current-carrying joints.

Table 2.4/1 Hexagon-Head Bolts and Screws, Grade 8.8

Size Finish Lubrication Torque, Nm_{± 10%} Torque, lbf-ft_{± 10%}

M8 24.5 18.1 M10 zinc 49.0 36.1 M12 plated 84.0 62.0 M16 None 205 151 M20 430 317 M24 bright or 745 550 M30 black 1,520 1,120 M36 2,650 1,950

Table 2.4/2 Studs, Grade 5.8

Size Finish Lubrication Torque, Nm_{± 10%} Torque, lbf-ft_{± 10%}

M10 29.5 21.8 M12 50.5 37.2 M16 Hot-dip 123 90.7 M20 Galvanized None 258 190 M24 447 330 M30 912 673 M36 1,590 1,170

Table 2.4/3 Stainless Steel Studs, Hex Head Bolts and Screws, Grade A2-70 or A4-70 to ISO 3506

Size Finish Lubrication Torque, Nm± 10% Torque, lbf-ft± 10%

M8 22 16 M10 lubricated 42 31 M12 with an 74 55 M16 bright anti-sizing 180 133 M20 compound 385 284 M24 600 443

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Chapter 2-8

2.5 Expansion Couplings

Stainless steel expansion couplings are installed in the top and bottom cooler oil pipes to allow limited axial and lateral misalignment during installation and to accommodate any settling of the anti-vibration pads after installation. Refer to Outline Drawing XTH 4605 01-EUH for location.

2.6 Transformer Mounting System

The transformer is provided with the correct number of anti-vibration pads to provide mechanical isolation. Position of the anti-vibration pads is detailed on the Transport of Transformer drawing XTH 4605 02-EUH.

During transport, the anti-vibration pads are secured to the main tank to facilitate unloading and placement at site before other crates containing accessories are opened.

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3

CONSERVATORS

3.1 Design of Conservator

The conservator is a reservoir, which takes up the extended volume of the oil of a transformer or rector tank. The volume of the conservator depends on the tank volume and the total temperature range.

All conservators have a level indicator. The divisions on the indicator dial may be calibrated to correspond to each 10% of the conservator volume or may be calibrated in degrees C to provide a general guide for estimating volume.

The connection between the float mechanism and the dial indicator is magnetic.

The level indicator is mounted under the conservator and the float moves vertically along the length of the conservator.

All pipe connections are from the bottom. Generally the center ones goes to the tank. This pipe extends 50mm inside the conservator to prevent any dirt from entering the main tank. The second pipe with a valve is for draining. The third connects the conservator to the Silca Gel breather. The latter pipe extends inside the conservator all the way to the top and has a special sticker next to the connection flange to identify its function.

3.2 Oil Conservator with Air cell

This procedure is for transformers equipped with transformers equipped with oil conservators with an air cell, which prevents contact between the oxygen in the air and the transformer oil. The air cell is like a balloon that fits the shape of the inside of the conservator and floats over the oil as the level rises.

3.2.1 Rubber Air Cell

The air cell is manufactured from reinforced, nitrile rubber with an internal barrier material on the inside (air side) that is resistant to ozone and other atmospheric agents. Refer to manufacturer’s documentation for details of construction and to Purchase Drawing for dimensions.

The air inside the cell is isolated from the conservator through a flange at the top center of both the conservator and the air cell. This flange is connected by a pipe to a dehydrating breather to prevent condensation inside the cell and the possible formation of ice in cold weather conditions.

When the conservator is vacuum proof, an extra flange is added next to the air cell flange and a U shaped pipe is supplied for interconnecting them temporarily during oil filling. This is to ensure that during the filling operation the pressure will be the same inside and outside the air cell.

The air cell is accessible from the inspection cover on the end of the conservator. The procedure to fit or replace an air cell is as follows:

1. Obtain two threaded rods (M12 or 1/2” UNC) about 400mm long.

2. Insert the rods through the holes of the air cell flange welded on top of the conservator for a length of 300mm using two nuts as stoppers.

3. Enter the conservator through the manhole and thread the rods into the air cell flange after putting the gasket in place.

4. Go back on top of the conservator, pull the threaded rods up and secure two of the flange bolts. The rods are then removed and the other two bolts are fixed. Two hangers on either side of the air cell flange need to be attached to their brackets inside the conservator.

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Instruction and Operation Manual INCO Larona Project Power Transformer Serial No. 512040

Chapter 3-10

CAUTION!

AIR OR GAS AT ATMOSPHERIC PRESSURE MUST NOT BE ADMITTED INTO THE CONSERVATOR ON THE OIL SIDE OF THE RUBBER CELL OR THE CELL WILL DEFLATE. THIS WILL CREATE A RISK THAT THE CELL WILL FULLY OR PARTIALLY COLLAPSE AND MAY RUPTURE WHEN SIGNIFICANT OIL EXPANSION OCCURS. DO NOT ATTEMPT UNDER SERVICE CONDITIONS TO BLEED AIR OR OIL FROM THE FILTER VALVE, THE GAS DETECTOR OR THE VENT PLUGS ON TOP OF THE CONSERVATOR. CONSERVATOR SHOULD BE BLED ONLY AFTER THE AIR CELL HAS BEEN PRESSURISED TO 10 KPA GAUGE.

3.2.2 Oil Filling

Oil filling is described in Chapter 11.3 for transformers with a System Voltage less than 200 kV, shipped with oil, for others see Chapter 11.1

Observe the following.

When during oil filling into the Transformer under vacuum, the oil level reaches to Buchholz relay and see oil flow at sight glass, close the vacuum valve,switch off vacuum machine and remove the vacuum hose, continue oil filling into conservator until oil level on the indicator reaches to the proper level according to the Oil level-Oil temperature chart, stop oil filling, break the vacuum in conservator by supply dry gas into conservator via vacuum valve until pressure balance to atmostphere, do not

close Equalizing valve of conservator before pressure balanced to atmostphere because unbalanced pressure can causes expolded and leaked at air cell.

Close the Equalizing valve of conservator, put 10 kPa or 1.5 psi air pressure in the air cell and open the two air bleeder valves on top of the conservator and close the bleeder valves when finished air bleeding.

Incase of oil fulfilled Buchholz relay and oil was filled around ¼ of the conservator volume but the oil level indicator pointer was not move up. It may causes by rubber air cell was fold down, and obstructed movement of float arm of the indicator. It needed to unfold the rubber air cell by stop oil filling, break vacuum and balance to atmosphere, close the Equalizing valve of conservator, put 10 kPa or 1.5 psi air pressure in the air cell to unfold the air cell membrane, see movement of oil level indicator, relief air pressure and remove the air hose, start oil filling for oil level adjustment and open vacuum valve for relief air from air cell during oil filling, gas bleeding when finished oil filling.

Disconnect all equipment and connect the air cell to the Breather.

3.2.3 Vacuum Oil Filling

1. Remove the pipe connecting the conservator to the breather and replace temporarily with a valve (not included, recommended 1” ball-valve) Keep it closed.

2. Remove the vacuum valve on the air cell flange and connect the two flanges on top of conservator using the U flanged pipe supplied. Follow instruction Chapter 11.5.

3. After filling remove the U shaped pipe and install the valve and a low-pressure regulator suitable for 10kPa on the air cell flange. Close the second flange with a cover and a gasket. 4. Put 10-kPa or 1.5 psi air pressure in the air cell. Open the valve at reduced flow (max 1800l/hr

or 500gal/hr) and pump until the oil starts coming out from both the bleeder valves. Close both bleeder valves and remove the pressure from the air cell simultaneously.

5. Continue pumping until the proper level is reached as specified on the nameplate. 6. Disconnect all equipment and connect the air cell to the breeder.

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It is important for any type of tap-changer, to pull vacuum in the tap-changer and the main tank simultaneously (selector switch for outside TP and diverter switch for inner TP). This is to prevent stresses on the partitions separating the device and the tank.

3.3 Oil Conservator without Air Cell

This procedure is for transformers equipped with oil conservators without air cell.

3.3.1 Oil Filling

Oil filling is described in Chapter 11.5

3.3.2 Vacuum oil Filling of conservator

1. Remove the pipe connecting the conservator to the Silca Gel breather and replace temporarily with a valve (not included, recommended 1” ball-valve).

2. When oil level reaches 100mm below the transformer tank cover, close the vacuum valve and stop the vacuum pump.

3. Keep filling the oil until the proper level in the conservator is reached as specified on the nameplate.

4. Close the oil valve; break the vacuum by opening the temporary valve. Remove this valve and reconnect the pipe to the breather.

It is important for any type of tap-changer, to pull vacuum in the tap-changer and the main tank simultaneously (selector switch for outside TP an d diverter switch for inner TP). This is to prevent excessive stresses on partitions separating the device and the tank.

3.4 On Load Tap Changer Conservator

The tap-changer conservator is an extension to the main conservator but completely separated from it with an endplate. This conservator has three pipe connections.

The length of this conservator is a function of the oil volume in the tap-changer. In order to ensure that the level of the oil will always be lower than the main conservator, the volume is calculated to be larger than the minimum required

Conservator is fitted with an oil level indicator. The Oil Level Indicator Plate is used in conjunction with the level indicator to correct the filling level depending on the average oil temperature.

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Instruction and Operation Manual INCO Larona Project Power Transformer Serial No. 512040

Chapter 4-12

4

PAINT SYSTEM

4.1

Preparation Before Painting

4.1.1 General :

This instruction is a basic document for surface treatment concerning corrosion protection and surface finish.

ABB Transformers general concept for painting of Power Transformers is based on the following philosophy.

For internal painting (surfaces in contact with transformer oil) the demands on corrosion resistance are limited, but due to high demand on cleanliness these surfaces shall be painted with a white semiglossy paint with good oil and heat resistance.

For external painting, the demands on corrosion resistance are extremely high. Power Transformers are often placed in heavily polluted atmospheres. Together with other transformer specific conditions, such elevated temperatures, this means high demands on the surface treatment and painting system.

ABB has chosen a Zinc rich primer as a first coating, followed by an intermediate primer barrier (also used for internal painting), and finally a coat of highly resistant polyurethane finish.

In the instruction, standard surface treatment for ABB Transformers is described. The data of the paint and drying times are given in the annexed files.

The workshop documents should contain reference to the correct instruction describing the selected method of surface treatment.

4.1.2. Definitions:

Weld-pearl or weld splash:Fixed or loose particles, metallic or non-metallic melted parts of welding electrodes or weld deposits.

Un justified bosses: May occur at weld-beads, at butt welds, back welds, electrode-exchange places, tacks, electrode striking verges, upsetting or rolling faults as warts or verges.

Unjustified cavities: May occur at melting ditches at the sides of the weld-beads, electrode- exchange places, electrode-striking verges, rolling faults as pits or verges, or as pits or verges appearing at handling

Deburring: implies removing of flashes of burrs, appearing on edges and corners at machining or handling. The machined edge shall be smooth without any burrs

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4.1.3. Directions:

Weld pearls or weld splashers must not appear.

Unjustified bosses must normally not be higher than 3 millimeter. If bosses and cavities are in direct connection with each other the height of these together must not exceed 3 millimeter, however, bosses caused by tacks must not be higher than 1 millimeter.

Unjustified cavities must not be deeper than 3 millimeter. If bosses and cavities are in direct connection with each other, the height of these together must not exceed 3 millimeter. Melting ditches may appear only if they are short (Ls), shallow (Ts) and without a sharp change over to the basic material.

Max length of melting ditch Ls = 0.5 * thickness of the thinnest goods thickness in the welding joint.

For welding class C, max. depth of melting ditch Ts = 0.1 * thickness of the thinnest goods thickness in the welding joint, but max 1 millimeter. For welding class B, max depth of melting ditch Ts = 0.05 * thickness of thinnest goods thickness in welding joint, but max 0.5 millimeter.

All corners and edges which are not specified with radius on drawing, shall be deburred. All machined surfaces shall be carefully protected against damages in form of blows and scratches.

All painted details shall have a varnish layer as smooth as possible.

All painted surfaces shall be hardened to such an extent that handling can be done without problems.

All painted details shall be handled with care during transport, storing and assembly.

4.1.4. Blast Cleaning:

Before the priming, all steel surfaces should be cleaned from dust, be descaled, be freed from slag and welding beads.

The steel surfaces should be shoot blasted to a degree of cleanliness Sa 2½ according to ISO 8501-1:1988. Immediately after blasting, the surfaces should be carefully cleaned from dust and sand by vacuum cleaning and brushing or blowing with dry air.

The priming must then start within one hour and be finished within eight hours.

4.1.5. Internal Painting:

Internal surfaces are spraying painted with one layer of BONDEX SX that is a high-build type Epoxy modified paint (white colour). The thickness of the dried layer must be minimum 50 µm.

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Instruction and Operation Manual INCO Larona Project Power Transformer Serial No. 512040

Chapter 4-14

4.1.6. External Painting:

Priming

The priming coating is prepared by spraying one layer of EPICON ZINC HB-2 that is a high-build anti-corrosive paint (grey colour). The thickness of the dried primer should be minimum 50 µm.

Intermediate painting

One intermediate paint layer of Epoxy modified paint BONDEX SX (white colour) is sprayed to form a coating on anti-corrosive paint base. The thickness of priming and intermediate coat painting together (in dried conditions ) should be minimum 170 µm.

Top coating

One layer of UNY MARINE based on Aliphatic Polyurethane resin (colour according to customer requirements in the order specification) is spray painted. The thickness of the total painting (priming, intermediate painting and top coating) must be minimum 220 µm.

4.1.7. Touch-up Painting:

Damages that have occurred on painted surfaces during assembly and transportation must be repainted.

The touch-up painting should restore the damaged layer of painting to the same quality and finish as for the surrounding surfaces.

Cleaning

The damaged part as well as the surrounding surfaces must be cleaned so that all grease, dust and other contamination are removed.

Priming

Damages on the prime painting layer and grinding through the primer to the steel surface must be repainted with primer to the stated thickness.

Top coat painting

All surfaces must be painted with intermediate coat paint before they are top coated painted. Top coat paint should be of the same supplier as the original painting is made of. The thickness of the touch-up painting must be the same as the original paint.

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Instruction and Operation Manual INCO Larona Project Power Transformer Serial No. 512040

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5

SHIPPING OF TRANSFORMERS

5.1 General

These instructions are intended to provide guidelines for the transport of transformers from ABB manufacturer’s premises to customer’s site to maintain their quality and reliability.

The instructions are intended for the guidance of personnel who have been trained for, or who have experience in transportation of heavy electrical power equipment, including the use of good safety practices. These instructions are intended to supplement, and not eliminate, the necessity for such training.

5.2 Shipping Information

5.2.1 Transport of Transformer Drawing

Weights and dimensions of the main tank are indicated on the Transport of Transformer drawing. This drawing shows a three dimensional profile of the stripped down, as-shipped transformer tank. The centre of gravity in three dimensions along with distances to the tank extremities is indicated. Information is given as to whether the transformer is shipped in oil or in dry gas, (air or nitrogen) and the shipping weight with or without oil. The transport drawing also details any special lifting, handling or shipping bracing instructions.

5.2.2 Shipping Braces and Covers

Shipping covers, and sometimes special braces, are required for shipment. These braces and covers must be removed after arrival site during the re-assembly process. The covers and braces are identified in the shipping documentation and are painted a contrasting color, such as white, for easy identification.

5.3 Transportation

5.3.1 Impact Recorder

The use of a three-dimension impact recorder (also known as a bump recorder or accelerometer) to monitor the quality of the trip and to chronicle potential excessive shocks to the transformer is in many cases a standard and Customer specified requirement. An electronic or mechanical impact recorder may be used.

The impact recorder is mounted on the transformer. Core-form transformers are shipped upright with the transformer mounted on the rail car or truck such that the long axis is in the same direction as the direction of travel.

Figure 5.3.1 Plan view of transformer on rail car or trailer

Rail car or trailer Transformer

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Instruction and Operation Manual INCO Larona Project Power Transformer Serial No. 512040

Chapter 5-20 The impact recorder is mounted on the transformer to ensure:

a. the Longitudinal Acceleration direction lines up with the direction of travel;

b. the Lateral Acceleration direction lines up perpendicular to the direction of travel; and, c. the Vertical Acceleration will detect the up and down movement.

See separate instruction leaflet for handling of impact recorder.

5.4 Successful Shipment Verification

5.4.1 General

After leaving the factory, whenever the transformer and components are transferred from one mode of transportation (rail car, truck, ship, etc.) to another, checks should be made to confirm that shipping damage has not been sustained. These checks should be made before the equipment is moved from the transport mode. Since transformers are shipped partially disassembled, electrical testing to confirm fitness cannot be performed at this stage. Care must be taken to properly and completely perform the limited amount of inspection that can be done at this time.

In the event of apparent or suspected damage, claims must be made against the transport carrier, and the Factory and Customer are to be notified immediately.

5.4.2 Impact Recorder

Refer to separate instruction leaflet for instructions on removing impact recorder at final destination. The individual Factories will define acceptable impact levels for the Longitudinal, Lateral and Vertical Acceleration.

If the transformer and components are being inspected at an interim point at a change of transportation mode, the impact recorder should be monitored. The impact recorder should not be removed from the transformer until the transformer has reached the final destination.

The recorder is housed in a hard plastic padlocked case for protection and remains the property of ABB. The impact recorder is to be returned to ABB when transport and site installation of the main tank are complete.

5.4.3 Other Checks

If shipping weight and dimension limits allow, smaller transformers are shipped with all or most of the oil required in the main tank. Some of these smaller units may also be shipped with dry nitrogen or air in the gas space on top of the oil; this gas will be at a positive pressure when the transformer leaves the factory.

To reduce shipping weight, larger units are totally drained of oil and then filled with dry gas (nitrogen or air) to maintain winding and insulation dryness during transit. Of the gas filled units, some will be filled in the factory and then be equipped with temporary gas cylinders for adding gas to the tank during transit as needed. Other gas filled units will leave the factory with an initial filling only and no supplementary cylinders added. In all cases, the gas filled units will leave the factory with a positive pressure of dry gas.

For transformer shipped in oil, check for oil leaks at valves, flanges, bushings and welded seams. If evidence of oil leaks is observed, contact ABB.

For transformers shipped in oil with gas layer on top of the oil, perform oil leaks checks and draw oil from suspect units. In addition, these transformers will be equipped with a vacuum/pressure gauge to monitor the gas layer pressure. This gauge must be checked and value of pressure/vacuum noted along with the oil temperature as read from the oil temperature gauge.

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For transformers shipped dry gas filled, the monitoring of the vacuum/pressure gauge and the temperature gauge is critical and is often checked at various stages of the journey. A leak will compromise the winding and insulation integrity. The pressure and temperature gauge values must be recorded and compared to the readings obtained in the factory prior to shipment. The transformers are shipped with a positive pressure but a negative (vacuum) reading may occur if the ambient temperature is substantially lower than recorded in the factory. The worst-case condition is a reading of zero pressure, which may be indicating a leak. In conditions of zero pressure or a pressure/temperature relationship that conflicts with the factory results, a dew point measurement may be taken. The dew point measurement will establish the moisture content of the gas, which can be compared to the measurement made in the factory prior to shipment.

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6

OFF LOADING AT SITE

6.1 Inspection Before Off-Loading

Upon arrival at site and before off-loading from any kind of vessel or carrier, the transformer should be carefully inspected before unloading. In order to maintain the warranty, the Receiving Inspection Checklist must be completed for each unit by the Purchaser's Representative or by an ABB Representative and returned to ABB Power Transformers.

Shipping papers, packing list with transport outline drawings, instruction leaflets and other pertinent documents furnished with the transformer must be available for use during the inspection.

If there is no evidence of shipping damage, proceed to off-load the transformer. If shipping damage is found, contact the nearest ABB Power Transformers representative for further instructions prior to off-loading the transformer.

Written notations of apparent loss and damage must be made on the carrier’s delivery receipt. Concealed damage must be reported immediately to the delivering carrier with a request for an inspection.

In the event of apparent or suspected damage, claims must be made against the transport carrier, and the Factory and Customer are to be notified immediately.

Parts which belong together during the assembly, and which have been mounted together in the factory, are also packed together, as an "Assembly Package" and identified in the Packing List. An "Assembly Package" may consist of several crates or boxes belonging together.

Large transformers may have side-mounted bushing turrets or tap-changer compartments that contain assembled insulated parts. They are taken off in the factory, sealed with large covers, and filled with dry gas under over-pressure in the same way as the main tank.

All such components shall be handled with great care, and left intact as long as possible. Under long-time storage they shall be included in the supervision scheme for the main tank.

The following is a general listing of tests and checks that should be performed on shipped transformers:

6.1.1 Transformers Designed with Oil Conservator, Shipped Oil Filled and Complete.

1. Measure the core insulation resistance to ground. The minimum acceptable value is 500 kohms when measured at 1000 VDC, corrected to 20 °C.

2. Are all tie rods undamaged and nuts tight, all cables tight? 3. Is all blocking tight and in good condition?

4. Is there any evidence of load shifting in transit?

5. Does the impact recorder indicate any extreme impacts? In doubtful cases contact ABB representative.

6. Are there indications of external damage such as broken glass on gauges, broken welds on flanges?

7. Is the paint finish damaged?

8. Are all fittings, which were shipped attached, still in place and undamaged (see the outline drawings).

9. Is there any evidence of oil leakage around valves, fittings, flanges and tank seams?

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Instruction and Operation Manual INCO Larona Project Power Transformer Serial No. 512040

Chapter 6-24

11. Is oil level in bushings normal? (This is checked after opening of boxes.)

12. Check the Packing List to confirm delivery of all major components and accessory boxes. 13. Do crates or boxes show evidence of damage or moisture entrance?

14. Check that detached radiators, coolers and pumps have openings closed off with blind flanges and plugs.

Shipped Oil Filled and Partially Disassembled.

1. Measure the core insulation resistance to ground. The minimum acceptable value is 500 k ohms when measured at 1000 VDC, corrected to 20 °C. Are all tie rods undamaged and nuts tight, all cables tight?

2. Is all blocking tight and in good condition? 3. Is there any evidence of load shifting in transit?

9. Inspect bushings that are assembled to the tank, or are in crates or boxes, for signs of breakage; are they chipped or otherwise damaged?

13. Check that the temporary shipping silica gel breather, moisture ingress will be indicated by desiccant changing color.

Shipped Dry-Gas Filled and Partially Disassembled.

1. Measure the core insulation resistance to ground. The minimum acceptable value is 500 k ohms when measured at 1000 VDC, corrected to 20 °C. Measure core to tank, core to clamps and clamps to tank.

9. Is the pressure in the gas filled transformer tank acceptable according to Chapter “MONITORING DRY-GAS FILLED TRANSFORMERS DURING SHIPMENT AND STORAGE”?

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6.1.2 Transformers Designed with Sealed Tank and Gas Space Shipped Oil Filled and Complete.

1. Measure the core insulation resistance to ground. The minimum acceptable value is 500 k ohms when measured at 1000 VDC, corrected to 20 °C

If the transformer is equipped with Inertaire® Oil Preservation, the Inertaire control cabinet generally remains on the transformer for shipment. If it was removed, install the cabinet and the nitrogen bottle. If the cabinet is already mounted, install the nitrogen bottle and connect the piping to the control. The tubing connection from the cabinet to the gas space has not been connected during transport. This prevents oil from entering the line during shipment. Check the line, to be certain it is clear of oil, and connect the tubing at the cabinet. The nitrogen supply valve should remain closed. If the transformer is equipped with Sealedaire® oil preservation, the pressure-vacuum relief valve assembly generally remains on the transformer for shipment. The system can be placed in service after performing the procedures and checks described in the Sealedaire leaflet.

Shipped Oil Filled and Partially Disassembled.

1. Measure the core insulation resistance to ground. The minimum acceptable value is 500 k ohms when measured at 1000 VDC, corrected to 20 °C.

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Instruction and Operation Manual INCO Larona Project Power Transformer Serial No. 512040

Chapter 6-26 7. Is the paint finish damaged?

If the transformer is equipped with Inertaie® Oil Preservation, the Inertaire control cabinet generally remains on the transformer for shipment. If it was removed, install the cabinet and the nitrogen bottle. If the cabinet is already mounted, install the nitrogen bottle and connect the piping to the control. The tubing connection from the cabinet to the gas space has not been connected during transport. This prevents oil from entering the line during shipment. Check the line, to be certain it is clear of oil, and connect the tubing at the cabinet. The nitrogen supply valve should remain closed. If the transformer is equipped with Sealedaire® oil preservation, the pressure-vacuum relief valve assembly generally remains on the transformer for shipment. The system can be placed in service after performing the procedures and checks described in the Sealedaire leaflet.

Shipped Dry-Gas Filled and Partially Disassembled.

1. Measure the core insulation resistance to ground. The minimum acceptable value is 500 k ohms when measured at 1000 VDC, corrected to 20 °C.

9. Is the pressure in the gas filled transformer tank acceptable according to Chapter “MONITORING DRY-GAS FILLED TRANSFORMERS DURING SHIPMENT AND STORAGE”? 10. Inspect bushings that are assembled to the tank, or are in crates or boxes, for signs of

breakage; are they chipped or otherwise damaged?

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6.2 Off-Loading the Transformer

Most large power transformers arrive to their destination loaded on depressed centre cars for rail or road. The transformer must have the shipping braces and blocking removed from the car, and then be lifted or skidded from the car to the correct position at the installation site.

CAUTION!

FAILURE TO FOLLOW THESE INSTRUCTIONS MAY RESULT IN EQUIPMENT DAMAGE OR PERSONAL INJURY.

Locate the car on a straight and level section of track, set the brakes on both ends of the car, and place chock blocks under the wheels at both ends. This will prevent movement of the car during the off-loading operations.

After the receiving inspection has been completed, remove the tie rods and the blocking from the car, Figure 6.2/1

Figure 6.2/1 Transformer shipment showing tie-rods and blocking

When the blocking has been welded to the car, use an acetylene-cutting torch and burn the blocking from the car bed, Figure 6.2/2. Do not attempt to burn the blocking at the point where it fits to the transformer base because this will damage the transformer paint finish and may damage the tank wall and cause an oil leak.

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Chapter 6-28

Figure 6.2/2 Blocking

6.2.1 Off-Load With Overhead Crane

If an overhead crane with sufficient capacity is available to lift the transformer from the car; this is the most convenient method to unload the transformer. Use a spreader bar, or slings with sufficient length to achieve a lifting angle small enough to meet the requirements given in the transport or outline drawing. Attach the slings to the lifting hooks on the transformer. The lifting hooks will be shown on the outline drawing and are generally located at all four corners of the tank. Do not attempt to lift the transformer from any point other than the designated lifting hooks.

Do not allow the slings to come in contact with any accessory items such as indicating instruments or bushings.

6.2.2 Off-Loading When Overhead Crane is Not Available

If a suitable overhead crane is not available, the transformer must be raised from the car bed with jacks, and then skidded or rolled into the desired position.

Figure 6.2.2/1 Jacking Pad

Place lifting jacks at the points near the base that are designated jacking pads - Figure 6.2.2/1. Operate the jacks at all four lifting points simultaneously so that the transformer base is kept level during the jacking. (Do not locate the jack base directly on the car bed.)

Block the car frame before the transformer is jacked up to keep it stable during the off-loading and skidding operation.

WARNING!

BE CERTAIN THE JACKS ARE SECURED DIRECTLY UNDER THE JACK PADS ON THE TANK SO THEY WILL NOT SLIP OUT OF POSITION DURING THE LIFTING OPERATION. FAILURE TO DO THIS MAY CAUSE EQUIPMENT DAMAGE AND SEVERE PERSONAL INJURY.

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Figure 6.2.2/2 - Transformer raised. Cribbing placed under transformer.

Jack the transformer approximately 20 to 25 cm (8 to 10 inches) above the car bed and slip successively heavy timbers or rails between the transformer and the car bed. The free clearance up to the transformer bottom during the jacking operation shall, for safety reasons, never exceed 5 cm (2 inches). The timbers should be located at the same point that planking was placed on the car bed when the unit was loaded. The timbers or rails should extend beyond the width of the transformer base to be certain the base is not damaged during the off-loading operation.

Lower the transformer on to the timbers and remove the jacks. Construct cribbing along the side of the rail car up to the same height as the top of the timbers under the base. Skid the transformer from the rail car onto the cribbing. Be certain to use only the designated pulling eyes when you move the transformer.

Do not allow the pulling cables to contact any piping or cooling equipment that may be installed on the transformer.

Set up the lifting jacks at the jacking point on the transformer and raise if off the cribbing. Remove one layer of max. 5 cm (2 inches) of the cribbing from under the transformer. Lower the transformer to the next layer of cribbing, reposition the jacks, and lift the transformer off the cribbing and remove another layer of cribbing. Continue this procedure until the transformer can be placed on the rollers or skids and moved to the prepared pad.

Figure 6.2.2/2 illustrated skidding on timbers and Figure 6.2.2/3, application of rollers. Keep the base level at all times.

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Instruction and Operation Manual INCO Larona Project Power Transformer Serial No. 512040

Chapter 6-30

Figure 6.2.2/3 Transformer raised. Cribbing and rollers placed under transformer.

Be certain to support the base of the transformer as shown on the outline drawing or the base drawing when you unload it from the car and move it to the foundation.

Use the designated pulling eyes and move the transformer to the prepared pad on rollers or skids and lower the transformer onto the pad. Check to be certain the base is level and proceed with the assembly and oil filling process.

If rollers are used, they should be located directly under the two walls parallel to the direction of movement. Rollers should be used on each side with a maximum centre-to-centre distance between rollers of one meter, or three feet. Failure to keep the rollers within the designated support area of the base may damage the tank bottom.

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7

MONITORING DRY-GAS FILLED TRANSFORMERS DURING

SHIPMENT AND STORAGE

WARNING!

NITROGEN GAS IS SOMETIMES USED INSTEAD OF DRY AIR. IN THESE CASES, A WARNING LABEL IS AFFIXED TO THE TANK. THIS INSTRUCTION IS VALID FOR BOTH DRY AIR AND DRY NITROGEN.

These transformers are shipped without oil and with accessories and fittings removed. The tank has been filled with dry gas to a slight over-pressure in the factory. It is important that the transformer remains perfectly sealed during shipment and storage. The gas pressure shall be monitored at regular intervals.

7.1 With Gas Cylinders

A gas cylinder with automatic pressure control has been fitted to the tank. The equipment shall be monitored at intervals.

7.1.1 Pressure Control Unit (typical)

Refer to Figure 7.1.1 for details of gas cylinder with automatic pressure control.

7.1.2 Pressure Limits

The gas pressure in the tank when the transformer leaves the factory is 25 kPa (3.5psi) at a temperature of about 30°C. This pressure will change with the ambient temperature, see Figure 7.1.2 Even at -25°C there should be a small positive over-pressure and in a warm climate the pressure still is about 30 kPa.

0 10 20 30 -20 -10 0 10 20 30 TemperatureOC Pressure kPa

Figure 7.1.2 Correct pressure at different ambient temperatures

If, for any reason, the internal over-pressure would drop below the value, which is set on the reduction valve, 3.5 kPa (0.5 psi), then dry gas will be automatically fed from the cylinder into the tank.

If the pressure in the tank would rise to the upper limit of 35 kPa (5 psi), then the release valve (Item 5 in the figure) will open to atmosphere and release gas from the tank.

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Ins tr uc tio n a nd O pe ra tio n Ma nua l INCO L arona Proj ect Po w er T ran sf o rmer Seri al N o . 512040 A B B LIM IT E D – P ow e r T ra ns fo rm e r D ivis ion , T ha ila nd R ev is io n: O ri gi n al Chapt er 7-32 F ig ur e 7 .1 .1 Drawing of Aut o m a tic P re ssure Cont rol

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7.1.3 Inspection and Reporting

The pressure control unit shall be inspected during shipment to ensure that: a. the pressure in the tank stays above the minimum limit, and

b. there is still considerable pressure in the storage bottle.

If the over-pressure in the tank is completely lost and the bottle is empty, then there is a leak. It is possible that there may even have been under-pressure at some time (due to a sudden temperature drop) and moisture may have entered the tank. Complete loss of gas-filling pressure must be immediately reported for further action.

7.1.4 Long-Term Storage – Change of Bottles

When the transformer is under storage for longer time than one month, the filling pressure shall be checked and recorded. See information in Chapter “STORAGE ON SITE BEFORE ASSEMBLY”. If the unit is opened and pressurized again the pressure must be rechecked again after 24 hours. The pressure in the storage bottle may decrease with time. If it reaches 1 MPa it should be replaced with a new bottle.

WARNING!

GAS BOTTLES SHOULD NEVER BE CONNECTED DIRECTLY FROM THE BOTTLE TO THE TRANSFORMER TANK (BYPASSING THE AUTOMATIC PRESSURE CONTROL) AS THE PRESSURE COULD BUILD UP TO A VALUE HIGH ENOUGH TO BURST THE TANK.

The bottled gas shall have a guaranteed dryness corresponding to a dew point not above-40°C (-40°F).

7.2 Without gas cylinders

7.2.1 Pressure gauge and Filling Valve

A pressure gauge and filling valve are fitted under a protective cover on the side or on the top of the tank. There is either a transparent cover, through which the pressure gauge may be read without opening it, or marked steel cover. In the later case, make sure that the cover is put back properly after every inspection.

The pressure gauge has a range +- 60 kPa (+-10psi). The filling valve will accept a plastic tube with an inner diameter of 5-8 mm (1/4 inch).

7.2.2 Pressure Limits

The gas pressure in the tank when the transformer leaves the factory is 25 kPa (3.5psi) at a temperature of about 30°C. This pressure will change with the ambient temperature, see Figure 7.2.2. Even at -25°C there should be a small positive over-pressure and in a warm climate the pressure still is about 30 kPa.

0 10 20 30 -20 -10 0 10 20 30 TemperatureOC Pressure kPa

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Instruction and Operation Manual INCO Larona Project Power Transformer Serial No. 512040

Chapter 7-34

If, after inspection, the pressure is completely lost, there must be a leak somewhere. It is possible that there may even have been under-pressure at same time (due to a sudden temperature drop), and moisture may have entered the tank. Complete loss of gas-filling pressure must be reported immediately for further action.

If the pressure read on the gauge is not completely lost, but has fallen below 5 kPa (1 psi), then the tank shall be filled up with dry gas to the original reading of about 20 kPa.

The guaranteed dryness of filling gas shall be such that the dew point is below -40ºC (-40ºF). Before filling, the plastic hose used shall be blown clean with gas from the bottle.

7.2.3 Long-Term Storage – Change of Bottles

When the transformer is under storage for longer time than one month, the filling pressure shall be checked and recorded. See information in Chapter “STORAGE ON SITE BEFORE ASSEMBLY”. If the unit is opened and pressurized again the pressure must be rechecked again after 24 hours.

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8

STORAGE ON SITE BEFORE ASSEMBLY

8.1 General

This instruction deals with storage and supervision on the erection site, in particular if the shipment has arrived early, and the assembly will not take place immediately.

The transformer may have been shipped with some accessories and fittings removed. The tank may have been filled with dry gas or oil during the shipment.

The shipment consists of the “Main Unit” - the closed tank with core and coils, and crates and boxes having contents as indicated by the Packing List. The Main Unit shall preferably be placed on the mounting foundation, if it is ready, or on a suitable temporary pad. Be certain to support the base of the transformer as shown on the outline drawing or the base drawing to avoid deformation or damage of the tank bottom.

Crates and boxes are to be kept protected from weather, indoors when required, but may also be stored outdoors, supported off the ground, and well covered with tarpaulins.

8.2 Separate Storage of UN-MOUNTED Accessories

When accessories are not mounted immediately after the transformer is received, take care to protect them from damage or loss during storage. The following general instructions provide guidelines for storage and inspection. See also the manufacturers’ documentation for the individual parts for storage instructions.

Radiators and Coolers

The radiators are shipped with the top and bottom openings sealed airtight and watertight. Radiators should be stored on blocks to keep them off the ground.

Make visual inspection of vent and drain plugs to check for tightness. If they have been loosened, re-tighten before storage. Gaskets or Teflon sealing tape may be used for sealing plug threads.

Bushings

The bushings removed for shipment should remain in the shipping crates until they are required for the transformer assembly. Bushings are to be stored as described in the manufacturers’ documentation.

Load Tap-Changers

The load tap-changer will generally be shipped attached to the transformer. The tap-changer may be shipped detached from the main unit. In either case, all oil compartments of the load tap-changer must be filled with oil to positive pressure during storage. The electrical space heaters in the control compartments are to be connected to a power circuit and energized to keep the control equipment dry.

Fan Motors

Fan motors are typically mounted on the radiators and will be stored as per the radiator requirements.

Other Boxes

Boxes that are marked for protected storage will be stored in a clean, dry place.

Inertaire Equipment

The Inertaire equipment is shipped on the transformer when shipping clearances allow. The pressure gauge, reducing the valves, three-way valve, sump and plastic hoses are assembled and in the cabinet. Flexible tubing for connecting the nitrogen tank to the cabinet is shipped in the detail box.

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Chapter 8-36

Paint Finish

Inspect the paint finish on the main unit and all painted detail parts for damaged areas. Apply touch-up paint (primer and finish coat) to these areas as required.

8.3 Storage of Main Unit in Oil (for units shipped in oil)

With proper preparation and maintenance, transformers may be stored indefinitely if they are filled with oil.

As soon as possible after receiving the transformer, locate it on its permanent foundation, or a solid temporary foundation, and perform the required inspection and tests. Report any damage or shortage before storage. As many accessories as possible should be installed, and the remaining parts stored properly.

Transformers with sectionalised tanks or major components such as bushing turrets that have been removed for shipment must have permanent covers installed. If bushings are installed during storage they should be temporary connected (grounded) to the transformer tank.

Test oil from a bottom-sampling valve for chemical properties. If the transformer is being stored with a dry gas cushion on top of the oil, positive pressure must be maintained during storage. A record of temperature and gas pressure must be maintained. Record temperature and gas pressure daily for the first two weeks of storage, then weekly for the next month followed by monthly readings. If Inertaire equipment is being used, nitrogen consumption should be recorded.

If the transformer is shipped partly filled with oil and with air breather, the condition of the drying agent must be checked regularly according to detailed information in the manufacturer’s documentation.

After six months and subsequently on the Customer normal maintenance schedule, check the oil from the main unit and other oil filled compartments for chemical properties.

8.4 Storage of Main Unit in Dry Gas (for units shipped in dry gas)

If a transformer is to be stored for more than a few months prior to installation it is strongly recommended to oil fill prior to the storage period. When this is not practical, storage in dry gas is acceptable with following precautions.

In all cases where gas storage is performed it is necessary that positive gas pressure be maintained in the transformer tank at all times. If the unit is equipped for Inertaire, this can be used for maintaining pressure. If the unit does not have Inertaire, a temporary installation of the apparatus or other gas pressure control system can be made.

A record of temperature and gas pressure must be maintained. Record temperature and gas pressure daily for the first two weeks of storage, then weekly for the next month followed by monthly readings. If Inertaire equipment is being used, gas consumption should be recorded. In the event of loss of gas pressure, the dew point must be measured after restoration of pressure.

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9

RECEIVING AND HANDLING TRANSFORMER OIL ON

SITE

9.1 General

This instruction lists the main quality requirements that are to be fulfilled when transformer oil is delivered to an installation site for filling into the transformer.

The oil shall fulfill the requirements in material specification 1ZBA117 001-1, 2, 3 or 4.

The user of the transformer may have issued an oil specification of his own, or may have specified oil of a particular trademark from an internationally recognized supplier. This may add to, but does not relieve any of the requirements specified in this instruction. They are necessary for long-term reliable operation of the transformer.

9.2 Types of Oil

Transformer oils are specially refined products made from crude oils of different types from different wells. The different types of oil are characterised by origin and chemical composition. Terms such as napthenic, paraffinic, aromatic and aliphatic refer to different types of hydrocarbons in the oil, which are balanced by the manufacturer to give a combination of high insulation withstand strength, low viscosity, low volatility/high flammability temperature, low sulfur content, and low aging (oxidation) tendency.

At the present time there is no essential, documented difference in overall quality between materials from different crude origins, as long as the final products are manufactured by competent refineries and fulfill the requirements of the ABB material specification. A maximum of 10 % from a different oil base may be added to a primary oil supply.

When transformers are shipped from the ABB Transformer factory filled with oil, or when oil for the first filling is part of the delivery from ABB, it is supplied against ABB’s own Material Specification 1ZBA117 001-1, 2, 3 or 4.

9.3 Inhibited Oils

An inhibitor is a particular substance added to the oil in small quantities in order to neutralize certain intermediate "radicals" – agents in the process of oxidation of the oil. The result is a retardation of the aging, which continues until the quantity of inhibitor has been consumed. From that time onwards, the aging will proceed and accelerate freely.

The efficiency of the inhibitor depends on the degree of refining of the oil. Therefore, the best result is obtained if the oil is refined with the objective to be inhibited.

Some users hold the view that inhibitors should not be used because they may mask, for a while, the inherent aging properties of the oil and lull the operating staff into false security. After the inhibitor has been consumed, it may escape attention that the oil deteriorates more rapidly.

ABB Transformers does not share this view, and recommends inhibited transformer oil.

However, if a customer specification forbids inhibited oil, the filling will be made with un-inhibited oil complying with the relevant ABB material specification.

Note: The chemical short name for the usual inhibitor substance is DBPC (di-butyl-para-cresol). This must not be confused with the objectionable class of compositions, called PCBs (poly-chlorinated biphenyl’s - "askarels"). DBPC is not environmentally noxious - as a matter of fact it has an alternative use as a stabilizer agent in foodstuffs.

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Chapter 9-38

9.4 Supplier Certificate

The supplier of transformer oil shall guarantee, and supply a certificate that the oil, delivered from the refinery, fulfils the list of requirements specified in the actual ABB material specification 1ZBA117 001-1, 2, 3 or 4.

The quality of the oil at delivery condition shall be guaranteed through certificates of the oil characteristics from the oil in the transportation containers or through sample tests.

This certificate or tests shall include Power Factor/Dissipation Factor at 100°C or 90°C and the Interfacial Tension against water. These tests are to assure that no contamination of the oil has occurred during transportation and storage.

9.5 Sampling on Site

No specific sampling is required for certified oil. The following comments applied to non-certified oil. For transformers shipped dry-gas filled, bulk deliveries of oil in tank trailers are normally scheduled to arrive just in time for the filling procedure. This oil will be tested after final filling and processing. For transformer shipped oil filled, the top up oil may be delivered in drums. Oil in drums will be kept in storage with unbroken seals up to the time when filling procedures are to be commenced. The drums shall be stored in horizontal position, with the openings horizontal (at same height).

When the oil is delivered in drums and if it has to be