— 1ZSC0 0 0563 - ABJ EN, RE V. 1

Gas insulated wall bushings type GGFLTechnical guide

— Original instructionThe information provided in this document is intended to be general and does not cover all possible applications. Any specific application not covered should be referred directly to ABB, or its authorized representative.

We reserve the right to make technical changes or modify the contents of this document without prior notice. With regard to purchase orders, the agreed particulars shall prevail. ABB does not accept any responsibility whatsoever for potential errors or possible lack of information in this document.

We reserve all rights in this document and in the subject matter and illustrations contained therein. Any reproduction, disclosure to third parties or utilization of its contents – in whole or in parts – is forbidden without prior written consent of ABB.

— Table of contents

Design 5Shed form 8Transportation and storage 8Long term storage 8

Testing 9Standards 9Routine testing 9Type tests 9Test tap 9

Dimensions and data 10Electrical data 11Dielectric losses 11

Connection details 12Outer terminal 12

End-shields 13

Insulation gas 14Shipping 14

Gas monitoring 15

Mechanical loading 17Seismic tests 17

Short-time current 18

Ordering particulars 19

G A S I N S U L ATE D WA LL B U S H I N G S T Y PE G G F L TEC H N I C A L G U ID E 5

The GGFL type wall bushing is an SF6 gas-insulated bushing intended for use in HVDC valve halls. It can also be used in AC applications. Having no oil and no condenser core gives a lightweight, yet rigid, design.

The bushing was first introduced in Sylmar Converter station in Southern California 1992. It experienced and performed well during the 1994 Northridge earthquake. Later, seismic requirements were enhanced and the design improved even further by introducing a flexible bellow. The bellow stabilizes the conductor and is primarily used on larger bushings above 400 kV DC.

The design is suitable for horizontal (wall bushing) as well as vertical mounting (roof bushing) and any intermediate angle.

The bushing consists of an aluminum intermediate flange fitted with two composite insulators. The insulators consist of a glass fiber reinforced epoxy tube fitted with silicone rubber sheds for excellent electrical properties, also in rain and pollution conditions. The flanges of the insulators, which connect to the intermediate flange and to the cover of each high voltage end, are made of aluminum and are fastened with screws and nuts and provided with O-ring seals.

The current is carried from the outdoor outer terminal through the cover via a firmly attached multiple contact or welded to a tubular aluminum conductor. There is a corresponding arrangement at the indoor end to carry the current to the indoor outer terminal.

• Several different studs are available for the air side connections and may be selected to properly interface to the relevant current clamp.

• The standard color of the composite insulator is ANSI 70 light gray.

• Compared to other designs with conventional condenser cores, this design gives a bushing easy to handle due to its relatively low weight. The reduced number of different materials also gives an electrically stable solution. The main gas sealing interfaces are obtained from known and proven designs from gas-insulated substations.

• The bushing, being of a non-condenser core type, does not demand a capacitive test tap. For applications where on-line voltage divider is requested, a capacitive test tap can be provided by introducing an isolated floating shield in the wall flange.

—Design

6 G A S I N S U L ATE D WA LL B U S H I N G S T Y PE G G F L TEC H N I C A L G U ID E

Gas valve

CoverOuter terminal

Insulator

Intermediate flange

Bursting discRating plate

Cover

Cover

Silicone rubber sheds

Terminal

Terminal

Corona shield with support, only on GGFL 400 and 420,1ZSC001635-AAH and -AAL

Intermediate flange

Drain holes

Outdoor insulator

Indoor insulator

Fastening plane

Rating plate

M12 for grounding

Density guards

Rupture disc unit

Outdoor corona shield

Indoor corona shield

Flexible bellow

—01 Example no. 1 of GGFL bushing design.—02 Example no. 2 of GGFL bushing design.

—01

—02

G A S I N S U L ATE D WA LL B U S H I N G S T Y PE G G F L TEC H N I C A L G U ID E 7

CoverTerminal

Rupture disc unit

M20 for grounding

Density guards

Rating plate

Indoor corona shield

Flexible bellow

Indoor insulator

Intermediate flange

Outdoor insulator

Silicone rubber shedsCover

Outdoor corona shieldTerminal

Drain holes

Fastening plate

—03 Example no. 3 of GGFL bushing design, with measuring tap.—04 Example no. 4 of GGFL bushing design, with mounting plane of the intermediate flange perpendicular to the bushing center axis and outer terminal with hexagon mounting surface.

—03

—04

8 G A S I N S U L ATE D WA LL B U S H I N G S T Y PE G G F L TEC H N I C A L G U ID E

—05 Example of shed form.

—05

Table 1. General specifications

Application: Wall bushing

Classification: SF6 gas insulated bushing

Ambient temperature:

+60 °C to -30 °C, for use in valve halls or equivalent environments, other temperatures can be evaluated on request.

Altitude of site:< 1000 m. Bushings for other altitudes can be provided on request.

Type of insulating media:

SF6 gas at 5.7 bar absolute pressure at 20°C

Markings: Conforming to IEC/IEEE

Shed formThe standard shed form for GGFL bushings is the anti-fog type with alternating long and short sheds. The specific creepage distance, and thus the total creepage for a given flashover distance may be tailored by altering the shed profile. This is fairly easy using the extrusion method to apply silicone sheds in a helical form. ABB GGFL bushings are usually provided with one of the standard profiles giving a creepage to flashover ratio in the range of 3.3 to 3.6. Some outdoor applications have been provided with a profile exceeding ratio 4.

The specific creepage distance have ranged from 23 mm/ kV DC in the Sylmar reference installation to about 40-50 mm/kV DC for some of the coastal installations.

In general, silicone rubber performs better than porcelain, and the need to apply silicone grease, as has been the case for many DC installations with porcelain, is not required with silicone rubber sheds. For special customer demands regarding creepage distance, other shed forms may be used.

Transportation and storageThe bushing must be protected from penetrating water if stored outdoors. This means that it must not be stored in areas where it can be predicted that the ground will become wet and muddy during heavy rain. Shelter the bushing from rain and snow with a tarpaulin or roofing.

The bushing is supplied with the gas volume filled with nitrogen gas (N2) at a pressure of 25 kPa. This pressure should be maintained during shipping and storage.

The bushings are normally delivered from ABB in boxes with the bushing supported by blocks and fiber boards. The boxed are marked with “Top end”. This information can be important and shows how the bushing is oriented inside the box.

Care must be taken when storing the bushings so that the silicone rubber sheds are not damaged. For instance, rodents, insects or birds can destroy the sheds. The largest bushings are delivered with shipping supports to secure the conductor during transport and storage. The supports must be removed, see the installation and maintenance for each GGFL type for further instructions.

Long term storageBushings for long term storage (>1 year) should be kept indoors with controlled temperature and low humidity.

18°

11°

R830

60

38

R55

60

G A S I N S U L ATE D WA LL B U S H I N G S T Y PE G G F L TEC H N I C A L G U ID E 9

—Testing

—06 Test tap.

—06

All manufactured parts are individually pressure tested during manufacturing.

Pressure testing of each individual bushing is carried out at 900 kPa (9 bar) overpressure and tightness test is carried out at 600 kPa (6 bar) overpressure according to IEC 60137 and IEC/IEEE 65700-19-03.

The bushing is protected from overpressures by a bursting disc installed on the intermediate flange or at the end cover depending on the design.

StandardsThe GGFL bushing is designed and tested according to IEC 60137, IEC/IEEE 65700-19-03, and IEEE C57.19.00-2004. For applications that call for different specifications, please contact ABB.

Routine testingThe bushing is routine tested according to applicable standards IEC 60137, IEEE C57.19.00 and IEC/IEEE 65700-19-03 for DC applications.

The tests include measurement of partial discharge quantity, tan δ, capacitance, dry power frequency withstand, and if applicable DC voltage withstand, polarity reversal test and insulation of test tap. Visual inspection and tightness/pressure tests of gas insulated bushings are performed and an individual routine test report is issued with each bushing.

Type testsComplete type tests have been performed and reports are available on request.

Test tapThe GGFL bushings provided with capacitive test taps have designs that comply with the standard ANSI/IEEE C57.19.01-1991 Type A Normally grounded tap.

The test tap is positioned on the intermediate flange.

For bushings without measuring tap, the capacitance of the bushing may be measured between the wall flange and the high voltage end.

10 G A S I N S U L ATE D WA LL B U S H I N G S T Y PE G G F L TEC H N I C A L G U ID E

—Dimensions and data

The design of the GGFL type wall bushing is highly flexible, and parameters can be selected within a wide range. Tables 2 and 3 are given as examples of applications previously installed.

Table 2. Mechanical data and dimensions.

Bushing Catalog number Dimension drawingMass with SF6 gas (kg)

Cantilever test load Nx1 min

Total length (m)

Creepage distance (mm)A-side/B-side Test tap Bellow

GGFL 450 1ZSC001982-AAA 1ZSC001981-AAA 125 3150 3.2 3600/3600 No No

GGFL 450 1ZSC001982-AAB 1ZSC001981-AAB 145 3150 3.9 3600/3600 No No

GGFL 450 1ZSC001982-AAC 1ZSC001981-AAC 135 3150 3.6 4507/3600 No No

GGFL 530 1ZSC002980-AAA 1ZSC002979-AAA 255 3150 4.0 5215/5215 No No

GGFL 378 1ZSC002980-AAB 1ZSC002979-AAB 407 4080 4.7 7693/5215 No No

GGFL 325 1ZSC002980-AAC 1ZSC002979-AAC 265 3150 4.2 7693/3445 No No

GGFL 530 1ZSC002980-AAD 1ZSC002979-AAD 302 3150 5.0 8932/5215 No No

GGFL 650 1ZSC002980-AAE 1ZSC002979-AAE 308 3150 5.2 6985/5746 No No

GGFL 650 1ZSC002980-AAF 1ZSC002979-AAF 270 3150 4.3 5746/5746 No No

GGFL 550 1ZSC002980-AAG 1ZSC002979-AAG 289 3150 4.8 5215/5215 No No

GGFL 857 1ZSC002994-AAA 1ZSC002993-AAA 495 4080 7.5 10348/10348 Yes No

GGFL 787 1ZSC002994-AAB 1ZSC002993-AAB 407 3150 6.0 7516/7516 Yes No

GGFL 782 1ZSC002994-AAC 1ZSC002993-AAC 434 3150 6.5 11764/7516 No No

GGFL 1050/420/3150 1ZSC004904-AAA 1ZSC004903-AAA 845 5000 7.1 10650/10650 No No

GGFL 1050/420/3150 LC 1ZSC004904-AAB 1ZSC004903-AAB 910 5000 7.7 10650/13250 No No

GGFL 1460 LF152001-E 2756040-95 1600 3150 11.5 25235/14400 Yes Yes

GGFL 1300 LF152001-L 2756040-101 1500 3150 10.4 9280/5850 Yes Yes

GGFL 1425 LF152001-P 2756040-106 1650 3150 11.3 21300/15900 Yes Yes

GGFL 1425 LF152001-R 2756040-111 1750 3150 11.8 23400/15900 Yes Yes

GGFL 400 1ZSC002776-AAA 1ZSC002641-AAA 1770 3150 11.5 20400/13500 No Yes

GGFL 600 1ZSC003517-AAA 1ZSC003272-AAA 2680 4350 14.4 21490/17100 No Yes

GGFL 800 1ZSC002777-AAA 1ZSC001668-AAB 4200 5000 18.8 36740/11430 No Yes

GGFL 150HC 1ZSC004904-AAF 1ZSC004903-AAF 836 4000 5.0 7200/7200 No No

GGFL 400HC 1ZSC003517-AAB 1ZSC003272-AAB 2325 6000 11.5 20000/13000 No Yes

GGFL 800HCL 1ZSC005399-AAB 1ZSC005398-AAB 6261 6000 20.6 40000/23200 No Yes

GGFL 550 1ZSC002777-AAE 1ZSC001668-AAE 3076 6000 14.4 26900/17100 No Yes

GGFL 1100 1ZSC005399-AAA 1ZSC005398-AAA 7605 6000 26.2 51000/32500 No Yes

G A S I N S U L ATE D WA LL B U S H I N G S T Y PE G G F L TEC H N I C A L G U ID E 11

Table 3. Electrical data.

Bushing Catalog numberRated voltage(kV DC/kV AC)

Rated current(A DC/A AC)

Lightning impulse(kV)

Switching impulseDry/wet (kV)

2h DC (kV)

Polarity reversal(kV)

Dry power frequency(kV)

Capacitance C/C1/C2 (pF)

GGFL 450 1ZSC001982-AAA 175/145 1300 450200/Not tested

Not tested

Not tested 275 100/N.A/N.A

GGFL 450 1ZSC001982-AAB 175/145 1500 450200/ Not tested

Not tested

Not tested 275 140/N.A/N.A

GGFL 450 1ZSC001982-AAC 175/145 1500 450200/ Not tested

Not tested

Not tested 275 105/N.A/N.A

GGFL 530 1ZSC002980-AAA 210/170 1670 600 500/500 276Not tested 325 100/N.A/N.A

GGFL 378 1ZSC002980-AAB 210/170 1100 530504/Not tested 276

Not tested 230 110/N.A/N.A

GGFL 325 1ZSC002980-AAC 210/170 1100 325314/Not tested 219

Not tested 230 100/N.A/N.A

GGFL 530 1ZSC002980-AAD 210/170 3150 530413/Not tested 302 252 230 110/N.A/N.A

GGFL 650 1ZSC002980-AAE 210/170 3150 650543/Not tested 315 252 422 130/N.A/N.A

GGFL 650 1ZSC002980-AAF 210/170 2250 650 504/450 276 252 275(Wet) 100/N.A/N.A

GGFL 550 1ZSC002980-AAG 210/170 2250 550 504/450 276 252 275(Wet) 145/N.A/N.A

GGFL 857 1ZSC002994-AAA 320/245 3150 857854/Not tested 552

Not tested 477 212/80/240

GGFL 787 1ZSC002994-AAB 320/245 3150 840700/Not tested 504 420 395 170/70/220

GGFL 782 1ZSC002994-AAC 320/245 3150 840700/Not tested 450

Not tested 395 170/N.A/N.A

GGFL 1050/420/3150 1ZSC004904-AAA 320/420 3150 1050

950/ Not tested 480 400 570 120 /N.A/N.A

GGFL 1050/420/3150 LC 1ZSC004904-AAB 320/420 3150 1050 950/850 480 400 570 120 /N.A/N.A

GGFL 1460 LF152001-E 515/550 3000 1460 1175/1175 773 644 680 - /140/230

GGFL 1300 LF152001-L 500/550 3150 1300 1200/1200 765 640 575 -/155/230

GGFL 1425 LF152001-P 515/550 3150 1425 1350/1175 773 644 657 -/155/230

GGFL 1425 LF152001-R 500/550 2250 1425 1300/1300 750 644 630 -/155/390

GGFL 400 1ZSC002776-AAA 400/550 4000 903 825/825 612 510 442 235/N.A/N.A

GGFL 600 1ZSC003517-AAA 600/700 3500 1675 1448/1448 921 768 740 250/N.A/N.A

GGFL 800 1ZSC002777-AAA 800/900 4000 1800 1600/1600 1224 1020 883 260/N.A/N.A

GGFL 150HC 1ZSC004904-AAF 150/- 6250 700 -/600 270 188 325 173/172/N.A

GGFL 400HC 1ZSC003517-AAB 400/- 6250 980 -/880 612 510 500 N.A/209.7/N.A

GGFL 800HCL 1ZSC005399-AAB 800/- 6250 1870 -/1675 1224 1020 890 N.A/341/N.A

GGFL 550 1ZSC002777-AAE 550/- 5523 1350 -/1200 867 713 688 N.A/206/N.A

GGFL 1100 1ZSC005399-AAA 1100/- 5523 2420 -/2100 1650 1403 1273 N.A/371/N.A

extremely low dielectric losses. This feature of the GGFL bushing has given an application in the ABB HVDC Light projects, connecting the phase reactor to the HVDC valve. Due to the switching of bipolar transistors in HVDC Light, a large amount of harmonics at high frequency are produced. Any other types of bushing with solid or liquid insulation easily overheat in this position, due to dielectric loss. The GGFL can handle these harmonics due to both the low capacitance as well as the inherent low loss properties of the gas.

Electrical dataTypical rated order specific values for installed bushings are shown in the table below. These ratings are in many cases not the limit for each specific bushing and other combinations may be provided.

Dielectric lossesDue to the low dielectric loss of SF6, in theory close to zero loss for ideal pure gas, the bushing has an extremely low dissipation factor (tan δ). For DC voltages this is of less concern, but for alternating voltages the bushing displays

12 G A S I N S U L ATE D WA LL B U S H I N G S T Y PE G G F L TEC H N I C A L G U ID E

—Connection details

Outer terminalThe outer terminal is available in any design requested. Typically, an aluminum terminal stud with stud length 140 mm and diameter 60 mm is specified for currents up to and including 2500 A. Current demands over 2500 A have a terminal switch stud length of 140 mm and diameter of 80/130mm, made of copper.

The outer terminal contact force is achieved with six M10 screws. The contact area is protected by an O-ring gasket assembly.

The outer terminals for GGFL 150HC, 400HC, 800HCL, 550 and 1100 are equipped with built-in stud covers. The covers are screwed and sealed with O-rings to the end covers of the bushings.

The contact surfaces of the terminal studs are silver coated, and withstand currents over 2500 A.

—07 Terminal GGFL 400, 600 and 800.—08 Terminal GGFL 420.—09 Terminal stud cover.

Terminal

Washer

Torque 40 Nm

O-ring

Terminal

Terminal

Conical spring washer

Conical spring washer

Large washer

Large washer

Torque 40 Nm

Torque 40 Nm

O-ring

O-ring

—07

—08

—09

G A S I N S U L ATE D WA LL B U S H I N G S T Y PE G G F L TEC H N I C A L G U ID E 13

—End-shields

End-shields are necessary for corona-free operation at voltages exceeding approximately 200 kV DC or 170 kV AC rms phase-to-ground (300 kV system). The end shields are attached to existing screws at both ends of the bushing. For retrofitting, the bushing can be made to fit existing building and yard hardware.

Table 4. End shields.

Bushing Dimension drawing Corona shield outdoor Corona shield indoor

GGFL 450 1ZSC001981-AAA No corona shields are needed No corona shields are needed

GGFL 450 1ZSC001981-AAB No corona shields are needed No corona shields are needed

GGFL 450 1ZSC001981-AAC No corona shields are needed No corona shields are needed

GGFL 530 1ZSC002979-AAA 1ZSC003099-AAB 1ZSC003099-AAB

GGFL 378 1ZSC002979-AAB 1ZSC003099-AAB 1ZSC003099-AAB

GGFL 325 1ZSC002979-AAC 1ZSC003099-AAB 1ZSC003099-AAB

GGFL 530 1ZSC002979-AAD 1ZSC003099-AAB 1ZSC003099-AAB

GGFL 650 1ZSC002979-AAE 1ZSC003099-AAB 1ZSC003099-AAB

GGFL 650 1ZSC002979-AAF 1ZSC003099-AAB 1ZSC003099-AAB

GGFL 550 1ZSC002979-AAG 1ZSC003099-AAB 1ZSC003099-AAB

GGFL 857 1ZSC002993-AAA 1ZSC003099-AAA 1ZSC003099-AAA

GGFL 787 1ZSC002993-AAB 1ZSC003099-AAA 1ZSC003099-AAA

GGFL 782 1ZSC002993-AAC 1ZSC003099-AAA 1ZSC003099-AAA

GGFL 1050/420/3150 1ZSC004903-AAA 1ZSC001635-AAR 1ZSC001635-AAR

GGFL 1050/420/3150 LC 1ZSC004903-AAB 1ZSC001635-AAR 1ZSC001635-AAR

GGFL 1460 2756040-95 1ZSC001635-AAMRequired, usually provided by customer. Coordinated with bus-work.

GGFL 1300 2756040-101 1ZSC001635-AAMRequired, usually provided by customer. Coordinated with bus-work.

GGFL 1425 2756040-106 1ZSC001635-AAMRequired, usually provided by customer. Coordinated with bus-work

GGFL 1425 2756040-111 1ZSC001635-AAMRequired, usually provided by customer. Coordinated with bus-work.

GGFL 400 1ZSC002641-AAA 1ZSC001635-AAG 1ZSC001635-AAH

GGFL 600 1ZSC003272-AAA 1ZSC001635-AAK 1ZSC001635-AAK

GGFL 800 1ZSC001668-AAB 1ZSC001635-AAJ 1ZSC001635-AAB

GGFL 150HC 1ZSC004903-AAF 1ZSC003099-AAE 1ZSC003099-AAE

GGFL 400HC 1ZSC003272-AAB 1ZSC001635-ABC 1ZSC001635-ABC

GGFL 800HCL 1ZSC005398-AAB 1ZSC001635-ABE 1ZSC001635-ABE

GGFL 550 1ZSC001668-AAE 1ZSC001635-AAJ 1ZSC001635-AAB

GGFL 1100 1ZSC005398-AAA 1ZSC001635-AAW 1ZSC001635-AAV

14 G A S I N S U L ATE D WA LL B U S H I N G S T Y PE G G F L TEC H N I C A L G U ID E

—Insulation gas

The main insulation consists of pure compressed SF6 gas (sulfur hexafluoride). A N2 + SF6 mixture is used in extremely cold climates (below -30°C).

The two purposes of the compressed gas are to cool the tubular conductor and to provide insulation from ground. Its capacity for doing so depends on the density of the gas. The bushing is normally filled with gas at a pressure of 570 kPa (5.7 bar) absolute at 20°C. The filling is made through a gas connection valve on the intermediate flange. This valve can be connected through tubing to ground level to enable emergency topping up during service.

The pressure gauge, if used, is intended to give a locally visible check of the internal pressure of the bushing, roughly indicating whether the bushing has the correct gas density or not.

The SF6 gas density monitor may be set to give signals at a number of different levels, either for warning or to trip at low gas density. The quality of the SF6 gas should comply with standards IEC 60376 and 60796b “Specifications and acceptance of new sulfur hexafluoride”.

Gas and gas handling equipment are not included in the delivery from ABB. We refer to suppliers like Dilo and Svenska Transforfilter AB (Malmqvist) for purchase of gas handling equipment and gas.

ShippingThe bushing is shipped at a slight overpressure of 0.25 bar, with nitrogen gas. After installation and prior to operation a vacuum must be drawn so that air and humidity are removed and after that SF6 gas is added to the operating pressure (570 kPa abs. at 20°C).

G A S I N S U L ATE D WA LL B U S H I N G S T Y PE G G F L TEC H N I C A L G U ID E 15

—10 Density guard.

—10

Since the late 1990’s, each gas insulated bushing for HVDC projects has been supplied with two independent three-stage density switches. The devices are sometimes called “density monitors”, “pressure monitors” etc., but should more correctly be labeled “density switches”. The function is to activate one of three independent switching contacts, each one for a different density level of the insulating gas. The first is activated at a pressure of 530 kPa (5.3 bar) abs. at 20°C to indicate low gas density.

The second signal level is activated at 520 kPa (5.2 bar) abs. at 20°C to indicate very low gas density.

The third level gives an alarm at 500 kPa (5 bar) abs. at 20°C, which is the dimensioning density of the bushing.

At gas densities below 500 kPa the type test levels for dielectric strength do not apply. The ability of the bushing to conduct current declines progressively with falling gas density.

—Gas monitoring

The devices only activate the internal switches, and it is up to the user to connect and interpret the position of the switches in their alarm and monitoring system. Furthermore, “alarm settings”, “trip settings” etc. are often requested, but the devices themselves do not differentiate between “alarms” and “trips”, it is up to the user to decode, and perhaps at the third level, corresponding to the lowest density-pressure setting, the user may wish to trip or block the energized equipment for investigation.

Once again, sometimes the three levels are referred to as “alarm level 1” and “alarm level 2” and the third level considered a “trip level”.

It is important to remember that each of the three contacts is merely switching at each respective level, and whether each step is regarded as alarm or trip is defined by the user and should be adapted by the owner to the local procedures at each station. The units do not provide an active signal, and referring to items such as “alarm or trip signals from the density monitor” may lead to erroneous conclusions.

16 G A S I N S U L ATE D WA LL B U S H I N G S T Y PE G G F L TEC H N I C A L G U ID E

—11 Circuit diagram example.

Switch number D3 D2 D1

Ground

Terminal block number

P/T = nominal

34 31 32 24 21 22 14 11 12

The user is to connect a voltage control signal to a connection block for each switching step. The interpretation of the switch position is then made by checking which of the contacts is carrying the voltage, indicating if the gas density is above or below the pre-set level of engagement for switch action. The recommendation from ABB is to not operate the bushings at levels below the third stage, since the bushings are type and routine tested with a level three condition of the insulating gas. This implies the insulating characteristics of the bushings are guaranteed down to the lowest level of the density switch.

The third stage may thus in practice be regarded as a trip level – but this is decided and programmed into the user's alarm system.

When dealing with gas insulation it is preferred to deal with the concept of density. The insulating properties of SF6 are dependent on the density, the number of molecules in the enclosed space, and not directly the pressure, which could be compared to “how active” the molecules are.

This is the background to the devices being labeled as “density switches”, but for simplicity the pressure of the gas at a temperature of 20°C is commonly used. This can be seen in the descriptions below where a pressure level is related to a temperature. If dealing with density only, the temperature reference could be removed.

Thus, the nominal filling condition “the density giving a pressure of 570 kPa absolute at 20°C” is the correct interpretation. The same density gives a higher pressure at higher temperatures, and a lower at lower temperatures.

All references to pressure in the following description are referred to at 20°C.

—11

G A S I N S U L ATE D WA LL B U S H I N G S T Y PE G G F L TEC H N I C A L G U ID E 17

—Mechanical loading

The cantilever operational and test loads are given in Table 5. The force is applied at the center of the outer terminal of the bushing. For extraordinary requirements which include earthquakes, extreme environmental conditions and heavy equipment, consult the supplier. The tests are performed in accordance with IEC 60137 and IEEE C57.19.00.

Table 5. Mechanical loading.

Bushing Dimension drawing Max. cantilever operating load Max. cantilever test load

GGFL 450 1ZSC001981-AAA 1575 3150

GGFL 450 1ZSC001981-AAB 1575 3150

GGFL 450 1ZSC001981-AAC 1575 3150

GGFL 530 1ZSC002979-AAA 1575 3150

GGFL 378 1ZSC002979-AAB 2040 4080

GGFL 325 1ZSC002979-AAC 1575 3150

GGFL 530 1ZSC002979-AAD 1575 3150

GGFL 650 1ZSC002979-AAE 1575 3150

GGFL 650 1ZSC002979-AAF 1575 3150

GGFL 550 1ZSC002979-AAG 1575 3150

GGFL 857 1ZSC002993-AAA 2040 4080

GGFL 787 1ZSC002993-AAB 1575 3150

GGFL 782 1ZSC002993-AAC 1575 3150

GGFL 1050/420/3150 1ZSC004903-AAA 2500 5000

GGFL 1050/420/3150 LC 1ZSC004903-AAB 2500 5000

GGFL 1460 2756040-95 1575 3150

GGFL 1300 2756040-101 1575 3150

GGFL 1425 2756040-106 1575 3150

GGFL 1425 2756040-111 1575 3150

GGFL 400 1ZSC002641-AAA 1575 3150

GGFL 600 1ZSC003272-AAA 2175 4350

GGFL 800 1ZSC001668-AAB 2500 5000

GGFL 150HC 1ZSC004903-AAF 2000 4000

GGFL 400HC 1ZSC003272-AAB 3000 6000

GGFL 800HCL 1ZSC005398-AAB 3000 6000

GGFL 550 1ZSC001668-AAE 3000 6000

GGFL 1100 1ZSC005398-AAA 3000 6000

Seismic testsThe GGFL1300 designed for severe seismic requirements for southern California has been verified by a full-scale shake table test. This test is used as a reference for similar bushings.

18 G A S I N S U L ATE D WA LL B U S H I N G S T Y PE G G F L TEC H N I C A L G U ID E

—Short-time current

The rated thermal short-time current (Ith) is calculated according to IEC 60137. The rated dynamic current (Id) is 2.5 times the 1 second short-time current.

Table 6. Short-time current.

Bushing Dimension drawing Rated currentShort-time current Ith

kA, rms, 1sDynamic current IdkA, peak

GGFL 450 1ZSC001981-AAA 1300 50 125

GGFL 450 1ZSC001981-AAB 1500 50 125

GGFL 450 1ZSC001981-AAC 1500 50 125

GGFL 530 1ZSC002979-AAA 1670 50 125

GGFL 378 1ZSC002979-AAB 1100 50 125

GGFL 325 1ZSC002979-AAC 1100 50 125

GGFL 530 1ZSC002979-AAD 3150 50 125

GGFL 650 1ZSC002979-AAE 3150 50 125

GGFL 650 1ZSC002979-AAF 2250 50 125

GGFL 550 1ZSC002979-AAG 2250 50 125

GGFL 857 1ZSC002993-AAA 3150 100 250

GGFL 787 1ZSC002993-AAB 3150 100 250

GGFL 782 1ZSC002993-AAC 3150 100 250

GGFL 1050/420/3150 1ZSC004903-AAA 3150 100 250

GGFL 1050/420/3150 LC 1ZSC004903-AAB 3150 100 250

GGFL 1460 2756040-95 3000 100 250

GGFL 1300 2756040-101 3150 100 250

GGFL 1425 2756040-106 3150 100 250

GGFL 1425 2756040-111 2250 100 250

GGFL 400 1ZSC002641-AAA 4000 100 250

GGFL 600 1ZSC003272-AAA 3500 100 250

GGFL 800 1ZSC001668-AAB 4000 100 250

GGFL 150HC 1ZSC004903-AAF 6250 100 250

GGFL 400HC 1ZSC003272-AAB 6250 100 250

GGFL 800HCL 1ZSC005398-AAB 6250 100 250

GGFL 550 1ZSC001668-AAE 5523 100 250

GGFL 1100 1ZSC005398-AAA 5523 100 250

G A S I N S U L ATE D WA LL B U S H I N G S T Y PE G G F L TEC H N I C A L G U ID E 19

When ordering, please state:• Type and catalog number for bushing.• Catalog number for outer terminal.• Additional accessories or modifications.• Test required, in addition to the normal routine tests.

Ordering example:Bushing: GGFL1050/420/3150 1ZSC004904-AAAOuter terminal: Cu/Ag, D = 80 mm 1ZSC002786-AAC

—Ordering particulars

—ABB AB, ComponentsSE-771 80 LudvikaSwedenE-mail: sales@se.abb.com

www.abb.com/electricalcomponents

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