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ABB GSB 800 Скачать руководство пользователя страница 25

TR A N S FOR M E R BUS H I NG S T YPE G S B 8 0 0

I N S TA L L AT I O N A N D M A I N T EN A N C E G U I D E

25

2.15.3 Measurement of capacitance and tan

d

CAUTION

The voltage tap cover must never be removed when
applying voltage to the bushing. It must always be
grounded or connected to an external impedance.
No connection may destroy the bushing.

When not measuring, always make sure that the tap
cover is properly tightened with the gasket in place.
This is to prevent dust and water from entering the
voltage tap; see Fig. 32.

After mounting, a capacitance and tan

d

measurement is

recommended by connecting a measuring bridge between
the outer terminal and the voltage tap. This can be done
without removing the bushing from the transformer as the
bushing has an insulated voltage tap. More details can be

found in the product information 2750 515-142, "Bushing
diagnostics and conditioning".

With the transformer de-energized and the bushing outer
terminal disconnected from any power source, the voltage
tap cover can be removed. The measuring equipment is
connected to the voltage tap and the voltage measuring
source is connected to the bushing terminal.
The main capacitance C

1

is measured between the outer

terminal and the voltage tap. The tap capacitance C

2

is

measured between the voltage tap and the mounting flange.
These capacitances are also marked on the rating plate. The
nominal capacitance C

1

is given in Table 4.

Table 4. Nominal capacitances of C

1

(manufacturing tolerances ± 10%).

C

2

only as information.

Bushing GSB

CT = 600 mm

C

1 (pF)

C

2

(pF)

800

723

< 29,400

2.15.4 Check of resistance

The resistance measurement method depends on the
design of the transformer. In general, a current is applied
from bushing to bushing. The voltage drop from outer
terminal to outer terminal is then measured.

The resistance is calculated with Ohm’s law: U = R · I

U: Measured voltage drop

R: Total circuit resistance

I: Current

The total resistance is the sum of the transformer winding
and lead resistance, and the bushing conductor and contact
resistance. The additional resistance from the bushing with

the copper conductor should not be more than 100 µΩ. Since

the resistance of the HV winding of a typical power

transformer is in the order of 0.1… 1 Ω, this is a very rough

method that can only be used to detect very large faults in
the current path, such as disruptions.

Less-than-perfect contacts can only be detected by making
a sensitive measurement across each connection point, or
by measuring the temperature increase during operation
with thermo vision (infrared camera).

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Содержание GSB 800

Страница 1: ... 1ZSC000563 ABB EN REV 2 Resin impregnated paper bushing oil to air type GSB 800 Installation and maintenance guide ...

Страница 2: ...odify the contents of this document without prior notice With regard to purchase orders the agreed particulars shall prevail ABB does not accept any responsibility whatsoever for potential errors or possible lack of information in this document We reserve all rights in this document and in the subject matter and illustrations contained therein Any reproduction disclosure to third parties or utiliz...

Страница 3: ...and handling 8 2 6 Opening of crate 9 2 7 Lifting from the crate 10 2 8 Removal of protective hood 11 2 9 Removal of draw rod 12 2 10 Draw rod system 13 2 11 Flange grounding 20 2 12 Mounting of outer terminal 21 2 13 Oil filling of voltage tap housing 23 2 14 Waiting time before energizing 24 2 15 Recommended tests before energizing 24 2 16 Repacking of bushing after transformer FAT tests 26 3 Ma...

Страница 4: ...ves two conditions 1 Personal injury or death 2 Product or property damage includes damage to the bushing or other property as well as reduced bushing life Safety notifications are intended to alert personnel of possible risk of personal injury death or property damage They have been inserted in the instructional text prior to the step in which the condition is cited The following warnings and not...

Страница 5: ...scharge free bushing with low dissipation factor tan d A flange and composite insulator with silicone sheds are mounted and the space between the condenser core and the insulator is filled with insulating gel GSB uses the copper center tube as a current conductor where the oil side connection is made with a draw rod and a bottom contact The bottom contact is normally delivered with a standard end ...

Страница 6: ...itance C2 of the voltage tap 29 400 pF Conductor Center tube Inner terminal for flexible draw lead available on request Minimum creepage distance 27 500 mm Markings In conformance with IEC IEEE 1 3 Mechanical loading The cantilever operating loads for vertical and horizontal mounting and the test load are specified in Table 2 The force is applied at the center of the outer terminal of the bushing ...

Страница 7: ... number and serial number of the bushing and send them to ABB for comments 2 2 General tools Soft slings Shackles Ø 32 mm holes on the lifting adapters for connection of soft slings Torque wrench key for hexagon head screws head width 16 mm M10 and 13 mm M8 Tackle for mounting the bushing at a specific angle Soft bedding 2 3 GSB 800 tools to be ordered from the supplier Lifting adapter 1ZSC004867 ...

Страница 8: ...peratures the vaseline may appear as oil When removing the sealing tube be careful not to damage the tube gasket The sealing tube with the gasket drying agent and fasteners should be reassembled after the transformer test at a torque 50 Nm The metallic sealing tube on the oil side shown in Fig 5 must be mounted on the bushing during long term storage 1 year Protect the bushing from water when stor...

Страница 9: ... cover see Fig 6 3 Remove the tightening strap at the top end see Fig 7 4 The flange are fixed by a support block of wood Remove the screws at the flange from outside the crate the screws are holding the support block of wood After removing the screws remove the support block by lifting it upwards in its lifting strap See Fig 8 5 Lift the bushing from its crate according to section 2 7 06 Removing...

Страница 10: ...way as in the crate e g at the mounting flange and the outer terminal It may not be supported by the sheds CAUTION The sling at the outer terminal can be damaged by sharp edges Be sure to protect the sling from damage DO NOT lift at the silicone part of the composite insulator The silicone filling or fiberglass tube may be damaged It is important that the bushing is repacked in the same way as it ...

Страница 11: ... as support while disassembling the screws from the flange preventing the metallic hood to fall down on the painted surface on the bushing oil side See Fig 12 3 Carefully remove the protective hood See Fig 13 CAUTION Be carefull when removing the protective hood not to damage the painted surface of the bushing oil side 11 Support at flange and top piece 12 Use sling to support the hood while dismo...

Страница 12: ...AND MAINTENANCE GUIDE 2 9 Removal of draw rod See Fig 14 1 Unscrew the outer terminal and its gasket 2 Remove the nut and washers mounted on the draw rod inside the tube 3 Pull the draw rod out of the bushing from the oil side 14 Removing of the draw rod ...

Страница 13: ... the lower draw rod during transportation The lower draw rod can be used for supporting the bottom contact and the cables in the transformer tank during transport of the transformer reactor as shown in Fig 15 Mounting of the draw rod must be performed according to the described procedures Additional joint on request Standard joint locked at delivery Standard joint at flange level lower thread unlo...

Страница 14: ...ld clockwise approximately 20 and then release when in locked position Alternative 2 Mounting the standard end shield on the bottom contact Fig 18 1 Mount the socket screws with springs to the bottom contact 2 Connect the cable lugs to the bottom contact Tightening torque 68 6 Nm 3 Push the end shield gently against the bottom contact guiding the socket screws through the key holes 4 While applyin...

Страница 15: ...ng Lifting gear 1ZSC004867 AAA Upper draw rod Lifting adapters 1ZSC004867 AAB Joint at flange level until it is visible on the oil side and connect it to the top of the upper draw rod 4 The upper draw rod is now pulled through the bushing leaving the joint at flange level hanging outside the conductor tube or the standard end shield on the oil side 5 Raise the bushing according to steps 1 and 2 in...

Страница 16: ...e transformer 8 Place the bushing over the transformer reactor and connect the lower draw rod with the upper draw rod and firmly tighten 9 With the flexible pull through cord fully tensioned the bushing is lowered into the transformer reactor 10 Fasten the bushing flange to the transformer reactor and tighten according to the transformer reactor supplier s specified torque and remove the flexible ...

Страница 17: ...he measured distance b a 9 mm Each turn corresponds to an extension of 2 mm 14 Continue at section 2 11 to ground the bushing flange WARNING If the measured distance b a 9 mm is not achieved before reaching 160 Nm this indicates that the threads are too poorly lubricated If the threads are not damaged remove the nut and draw rod bolt to apply more Molykote Multilub and tighten again If the threads...

Страница 18: ...SFORMER BUSHINGS TYPE GSB 800 INSTALL ATION AND MAINTENANCE GUIDE 7 6 5 4 3 2 1 1 Bottom contact 2 Bottom contact adapter 3 Inner draw ring 4 Support tube 5 Jointing sleeve 6 Joint 7 Tube end 24 Draw rod system ...

Страница 19: ... lifted by the insulator Alternative 2 Raising the bushing to a specific angle 1 Place soft bedding e g a rubber mat or a wooden board under the bottom end of the bushing to avoid damage to the bottom contact or center tube 2 When raising the bushing to a specific angle the lifting gear and tackle must be arranged according to Fig 26 CAUTION The bushing must not be lifted by the insulator Lifting ...

Страница 20: ...screw M12 preferably stainless steel A4 80 Tighten to 40 Nm penetrating the paint of the transformer reactor down to the metal beneath This makes an electrical connection between the bushing and the transformer reactor keeping them at the same voltage Alternative 2 Connect a flexible cable between the M12 grounding hole in the bushing flange and a corresponding connection point on the transformer ...

Страница 21: ...rminal and the conductor tube 2 Carefully clean the contact and gasket surfaces 3 Lubricate the gasket with Mobilgrease 28 4 Assemble the tightening ring the gasket and the outer terminal stud and push them over the conductor tube Make sure that the tightening ring is mounted with the gasket track towards the gasket An extra gasket is supplied with the bushing and intended for final installation 5...

Страница 22: ...Make sure the screws and washers for mounting the corona ring to the bushing is included in the delivery Remove the plastic wrapping from the corona ring See Fig 30 Use a soft sling for lifting the corona ring Mount the corona shield on top of the top piece with screws Note that the metallic end at one of the spokes is bent curved to reduce the risk of mounting upside down See Fig 31 29 Removing o...

Страница 23: ...a space of approximately 6 10 mm for oil expansion 3 Firmly tighten the sealing plug The voltage tap adapter is used for permanent connection to measuring circuits see Fig 33 WARNING The voltage tap adapter must be equipped with suitable over voltage protection to prevent damage during service The cable gland must be oriented downwards in order to prevent water from entering the equipment If the c...

Страница 24: ...ounting but before connecting the outer terminal of the bushing to the rest of the switchyard power circuit 1 Tightness test between transformer and bushing flange 2 Tightness test of outer terminal 3 Measurement of capacitance and tan δ 4 Check of resistance 2 15 1 Tightness test between transformer and bushing flange Several different methods may be used for this test but we refer to instruction...

Страница 25: ...ween the outer terminal and the voltage tap The tap capacitance C2 is measured between the voltage tap and the mounting flange These capacitances are also marked on the rating plate The nominal capacitance C1 is given in Table 4 Table 4 Nominal capacitances of C1 manufacturing tolerances 10 C2 only as information Bushing GSB CT 600 mm C1 pF C2 pF 800 723 29 400 2 15 4 Check of resistance The resis...

Страница 26: ...ags with drying agent are enclosed see Fig 35 Open the bags and replace the used drying agent in the protective metallic hood on the oil side Fig 36 Discard the old drying agent Check that the seal for the metallic protective hood is in good condition and properly fitted on the hood sealing surface Fig 37 Reassemble the metallic hood to the flange at the oil side see Fig 38 Tighten the screws for ...

Страница 27: ...e crate The previous mentioned support for flange is made of two parts and after placing the bushing in the lower part the supports upper half shall be placed on the top side of the flange and secured by wood screws Fig 40 Also the top of the bushing shall be fixed by a clamping strap to the top end support which is a one piece support contrary to the flange support Fig 41 Lift the top cover in it...

Страница 28: ...ry are repacked Before sending busing to site check that there are a minimum of two crates one for bushing and one for the air side corona shield If there are lifting tools included in the order check that the third box is also sent to the transformer site together with the bushing 43 Repacking of corona ring 44 Check the number of transport boxes before sending to site ...

Страница 29: ... 3 2 Disposal after end of service life The GSB bushing is delivered in a wooden crate with a stainless steel sealing tube for moisture protection The bushing consists of the following The composite insulator consists of silicone rubber on a tube of fiberglass reinforced epoxy Between the insulator and condenser core there is silicone gel The resin impregnated paper RIP condenser core consists mai...

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Страница 32: ...ponents SE 771 80 Ludvika Sweden E mail sales se abb com www abb com transformercomponents 1ZSC000563 ABB en Rev 2 2018 04 15 Copyright 2018 ABB All rights reserved Specifications subject to change without notice ...

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