ABB Switzerland Ltd, ABB Switz erland Ltd, Micafil ... · ABB Switzerland Ltd, ABB Switz erland Ltd, Micafil Transformer high current bushings HIRIP / Technical guide Technical guide

ABB Switzerland Ltd,

ABB Switzerland Ltd, Micafil

Transformer high current bushings HIRIP / Technical guide

Technical guide

HIRIP | Technical guide (HLAB200429E) | ABB Switzerland Ltd, Micafil 2

Content

1. Scope ................................................................................................................................................................3 2. General information...........................................................................................................................................3 3. General design..................................................................................................................................................3 4. Packing..............................................................................................................................................................4

4.1. Bushing supply conditions.................................................................................................................................4 4.2. Repacking for further transportation .................................................................................................................4 4.3. Transport case ..................................................................................................................................................4 4.4. Lifting and handling ...........................................................................................................................................4

5. Storage..............................................................................................................................................................5 5.1. Proceedings after inexpert storage ...................................................................................................................5 5.2. Long term storage container .............................................................................................................................5

6. Installation and commissioning .........................................................................................................................5 6.1. Preparation before assembling .........................................................................................................................5 6.2. Cleaning, de-aeration and resting time .............................................................................................................6 6.3. Connections ......................................................................................................................................................6

7. Test tap .............................................................................................................................................................6 7.1. Purpose (test tap)..............................................................................................................................................7 7.2. Capacitance and dielectric dissipation factor tan(δ) measurements ................................................................7 7.3. Permanent measurements................................................................................................................................7 7.4. Insulation tests (test tap) ...................................................................................................................................7

8. Maintenance, repair, disposal ...........................................................................................................................8 8.1. Maintenance......................................................................................................................................................8 8.2. Spare parts........................................................................................................................................................8 8.3. Repair................................................................................................................................................................8 8.4. Disposal.............................................................................................................................................................8

9. Type Designation ..............................................................................................................................................9 9.1. Marking plate.....................................................................................................................................................9

10. Disclaimer of warranties and limitation of liability..............................................................................................9 11. Annex ..............................................................................................................................................................10

11.1. Measuring tap .................................................................................................................................................10 11.2. Measuring circuit .............................................................................................................................................11


1. Scope

This technical guide contains general procedures and guidelines to be followed from the time the bushings are received. These instructions do not cover all possible contingencies, which may arise during installation, operation, maintenance, and all details and variations of this equipment. Before installation and energizing, please consult the outline drawing for specific information. For additional information, contact your ABB Switzerland Ltd., Micafil representative.

ABB makes no warranty or representation and assumes no liability for the accuracy of the information in this document or for the use of such information. All information in this document is subject to change without notice.

2. General information

Type HIRIP bushings are designed for oil filled transformers and reactors and bus duct application on air side. Type HIRIP meets or exceeds the applicable requirements of the standards IEC 60137 and IEEE 57.19.01. Type HIRIP bushings are manufactured exclusively by ABB’s bushing manufacturing facility (MICAFIL) in Zürich, Switzerland.

3. General design

Type HIRIP is a dry oil free capacitive graded condenser bushing. The bushing condenser body consists of a solid core, made of wound crepe paper and inserted aluminium foils for electrical field grading. The paper winding is vacuum dried and subsequently impregnated under vacuum with a special epoxy resin. Vacuum drying, the impregnation of the paper winding with epoxy resin and the final curing are very sensitive processes. The upper part of the condenser is enclosed in a porcelain insulator with alternating sheds to provide the necessary creepage and arcing distance.

1. Aluminum conductor 1a. Silver plated terminals (air side) 1b. Silver plated terminals (oil side) 2. Porcelain insulator 3. Dry filling MICAGEL 4. RIP insulation core: The active part is made out of

Resin Impregnated Paper body with inserted aluminum foils

5. Mounting flange with integrated measuring tap 6. Current transformer extensions, if required

The space between the condenser and the porcelain insulator is filled with a specially formulated gel, so called MICAGEL, which after curing results in a hard rubber like consistency. This allows the bushing to be transported, stored and mounted in any position. The sealing system of the bushings makes the air side of the bushing virtually impervious to moisture from outside. The flange is fixed oil tight on the condenser core by a spring package for installation of the bushing onto the transformer. A measuring tap is installed on the main flange to determine capacitance and dissipation factor (tan δ) of the bushing. A lifting eye is provided in the top plate of the conductor for easier handling. Details of the construction of the bushing are to be read from the dimensional drawing.

1a

1

1b

3 2

5

6

4


4. Packing

4.1. Bushing supply conditions

For protection against damage, the bushings are dispatched in wooden transport cases. The bushings lower end is protected against humidity by a plastic bag with desiccant. The silver plated terminal areas are protected by plastic panels and grease.

4.2. Repacking for further transportation

It is necessary to ensure that the quality of packing, the protection against humidity and damage, is as good as on original delivery.

4.3. Transport case

Gross and net weight, also the dimensions are given in the dispatch notes.

4.4. Lifting and handling

- Removing the bushing from the shipping box Small types can be taken out by hand; larger types require ropes and lifting gear.

- Bringing the bushing into vertical position The easiest way is by means of two lifting gears and two ropes. One end of the rope is enlaced around the sheds close to the top; the other end is fixed with a hook into the eyebolt at the main flange. Those eyebolts can be screwed into the designated threading in the flange. The bushing is first lifted horizontally with both lifting gears synchronous. Then, the bottom part of the flange side is lowered down. In order to move the bushing vertically an eyebolt can be mounted at the upper end of the bushing. Prior to commissioning all eyebolts must be removed. The thread at the upper end of the bushing must be reclosed with the locking screw.

Attention: The lifting gear must not have sharp edges and should be of a soft type such as textile noose to avoid

damage to the insulator. The bushing must not touch the floor during lowering because the terminal area, the insulation body or any other parts might get damaged. The bushing must not be turned into a vertical position with only one rope, since the bushing could slip through the noose and fall down.


5. Storage Concerning the storage of the bushing, the location (outdoor, rain protected or indoor) and the duration of storage (short, medium or long term) must be taken into account. If necessary a storage container can be ordered from ABB Switzerland Ltd, Micafil. Caution: In general, the moisture protection for the bushing must be mounted at all times.

Outdoor, protected from rain Indoor Short term Max. 1 year

In original transportation box, covered with plastic. Recommended: Additional moisture protection with a second plastic bag or aluminium laminated foil and desiccant cartridge.

In original transportation box and original packed.

Medium term Max. 2 years

Not recommended Unpacked, in original transportation box. Only in dry rooms, temperature as constant as possible. The desiccant cartridge must be checked regularly.

Long term

Not recommended Lower part of the bushing in a storage container, filled with oil or dry nitrogen. or: In original transportation box and original packed. Only in dry rooms, temperature as constant as possible. The desiccant cartridge should be checked regularly. The bushing must be fully wrapped into laminated aluminium foil (PETP/Alu/PE). Quantity of desiccant: 2½ TME/m2 for moderate climate 25 TME/m2 for extreme climate TME/m2: Desiccant unit per m2 of the barrier surface.

Note: Bushings stored in special storage containers can be used immediately even after long-term storage without any further testing

5.1. Proceedings after inexpert storage It is possible that humidity diffuses into the insulation core. If you are suspicious whether the storage conditions were according above table or not, you can verify it by a capacitance and power factor tan(δ) measurement at about 10 kV test voltage applied onto the conductor. If the deviation of the power factor is too big or if you are uncertain about the conditions, please contact ABB Switzerland Ltd, Micafil for further information. Please also give information about the prevailing temperature at the time of measurement. 5.2. Long term storage container For long storage durations without special surveillance we recommend a protection with an oil filled storage container. In a normal case this assures the immediate availability of a bushing (e.g. spare bushing).

6. Installation and commissioning The bushing must have environmental temperature before installation to avoid condensation on the bushings surface. The transformer can be evacuated while the bushing is mounted on it. 6.1. Preparation before assembling The sealing area between the bushing flange and transformer tank should be free of corrosion. To tighten the system, O-rings or washers are suitable. The surface of the insulation core must not be clawed. The screw connection should be designed in such a manner to prevent deformation of the flange. If the threads of the eyebolts project from the bushings flange on the sealing side, they must be removed before tightening the flange. The eyebolts must be removed prior to commissioning. The thread at the upper end of the bushing must be reclosed with the supplied locking screw.


6.2. Cleaning, de-aeration and resting time The bushing must have environmental temperature before installation to avoid condensation on the bushing surface. The lower part of the bushing must be cleaned thoroughly with a clean, dry and non-fuffy fabric before installation. The transformer can be evacuated with mounted bushing. If the transformer is evacuated before oil filling no de-aeration is necessary. Attention: After de-aeration, high voltage ≥ Un / √3 should be applied to the bushing not earlier then 12 hours after

oil filling. 6.3. Connections When connecting to the bushing, common caution must be taken to reduce contact resistance. The silver coated contact surface of the terminals and flexible leads must be cleaned and degreased prior to connecting the conductor. To connect the conductor only use stainless steel screws, spring washers and disc springs. Each screw should apply a minimum load of 50 kNm onto the connection pad. The maximum tightening torque must not exceed 88 kNm. The bolts must be lubricated prior to tightening. The spring washers must (in a max. strained condition) have a minimum spring force of 50 kNm. Apply a screw lock to prevent loosening since constant vibrations are possible. Be aware, that the connections to the bushings terminals (on both sides) are not of rigid type. To avoid vibrations and dilatations being transmitted from the transformer to the connected line it is essential to have a flexible joint in-between. The bushing will be damaged if a rigid connection is made to the terminals because it is neither designed to compensate movements nor vibrations.

7. Test tap The test tap is an accessory on capacitance graded bushings that gives access to the ground layer insulated from the flange from the outside and thus to divide the total capacitance of the bushing into two sub-capacitances C1 (high voltage conductor - test layer) and C2 (test layer - flange). The test tap is designed in such a way that a connection between the test layer and the flange is automatically established, when the test tap is not in use. This connection can only be opened by completely inserting a 4 mm plug coupler or by connecting a plug converter (see figs. 2/3 in HLJM090044). For normal operation of the bushing the test tap must always be closed with the supplied cover for protection or the adapter. Attention: For connection only use the appropriate plug, according to HLJM090044 fig.2, or an adapter plug,

according fig.3. Never force the grounding spring with a tool! In service, the cover of the measuring tap must be installed at any time.

Warning: DO NOT OPERATE THE BUSHING WITH REMOVED CAP FROM MEASURING TAP, AS IT WILL

RESULT IN CORROSION OF THE GROUNDING CONTACT; DAMAGE THE BUSHING AND CAUSE ELECTRICAL FAILURE OF THE BUSHING AND THE TRANSFORMER. THE VOLTAGE ON THE MEASURING TAP MUST NEVER EXCEED 1,5 kV WHEN MEASURING POWER FACTOR. FAILURE TO FOLLOW THESE GUIDELINES COULD RESULT IN SEVERE PERSONAL INJURY, DEATH OR PROPERTY DAMAGE.


7.1. Purpose (test tap) The normal purpose of the test tap is to measure the capacitance C1 and its loss factor tan(δ). The most common test circuit for this purpose is shown in the enclosed drawing HLJM 118034. The test tap can also be used to carry out a permanent voltage measurement or partial discharge monitoring. The maximum permissible permanent voltage between the test layer and the flange is 1.5 kV. Depending on the rated voltage and the capacitance of the bushing the test tap can be loaded with 5-10 VA. An impedance must always be connected parallel to C2 to limit the voltage to ≤ 1.5 kV. This impedance is mostly a capacitance Cz that must have a minimum value:

21min1

5,13C

kV

UCC

N

z−

−

⋅⋅=

The values of C1 and C2 can be taken from the test report for the particular bushing. To get a specified voltage U, it is necessary to use a capacitance Cz:

min211

3z

N

zCC

U

UCC ≥−

−

⋅⋅=

To take reactive power from the test tap an ohmic resistor must be put in parallel to C2. The possible power P that can be taken from the test tap is:

( )22

2

13/

baR

UP

z

N

+⋅= with

1

21C

Ca +=

zRC

b⋅

=1

1

ω

However it is a requirement that U remains ≤ 1,5 kV. This can be checked with:

kVbaba

UU N 5,1

3/ 22

22≤+⋅

+=

Caution: Without additional external impedance, the voltage resulting by C1 and C2 is always higher than 1.5 kV

at the test tap. With live bushings either the test tap must be connected conductively with the flange or the divider voltage produced must be limited to 1.5 kV by adding impedance. Otherwise the bushing will be damaged and could explode!

The obtainable measurement accuracy depends on the changes of C1 and C2 as a function of the temperature of the bushing. It can be calculated with < 5%.

7.2. Capacitance and dielectric dissipation factor tan(δ) measurements After inserting a 4 mm plug coupler, the connection to a measuring bridge can be performed with a line with standard 4 mm banana plug. 7.3. Permanent measurements After insertion of a plug coupler acc. to HLJM151444, available from ABB Switzerland Ltd. MICAFIL, a shielded cable with N-type connector can be attached to the coupler (see page 17 in HLJM 090044). The cable used depends on the voltage and the shielding properties required. 7.4. Insulation tests (test tap) The insulation strength of the test tap of each bushing is checked with 3 kV for 1 min during the routine test of the bushing acc. to IEC 60137.


8. Maintenance, repair, disposal

8.1. Maintenance Prior to service of the bushing, carry out a measurement of dissipation factor tan(δ) and capacity C1 between high voltage conductor and test tap at voltage up to 10 kV in order to have a reference for later checks. Beside the occasional visual and thermal checks of the joints, as well as a cleaning of strongly contaminated insulators, no maintenance of the bushing is required. 8.2. Spare parts When ordering spare parts, always indicate serial number and type of bushing. 8.3. Repair Repair only after consulting ABB Switzerland Ltd, Micafil for instructions. Please always assure that the serial number, type of bushing and exact descriptions of damage are at hand. 8.4. Disposal After reaching the end of lifetime, this product must be disposed according to local laws and regulations. All the contained substances and material should be recycled separately. The product as a whole and its individual parts do not contain any toxins. Caution: The bushing is under high mechanical tension built up by visible spring cartridge on the oil side. The relaxation has to be accomplished with the necessary diligence and care. Neither breathing, skin protection nor any special precautions are required. Apply the common and appropriate safety standards to prevent accidents. In case of uncertainties please contact ABB Switzerland Ltd, Micafil for advanced information and instructions. SAFETY INFORMATION WHILE IN OPERATION, THE SCREWS MUST BE MOUNTED AND TIGHTEND AT ALL TIMES WITH STANDARD TORQUE. FAILURE TO FOLLOW THESE GUIDELINES MAY RESULT IN DAMAGE TO THE BUSHING AND CAUSE AN ELECTRICAL HAZARD. THIS COULD RESULT IN SEVERE PERSONAL INJURY, DEATH OR PROPERTY DAMAGE.


9. Type Designation

The type description for high current bushings is as follows: RTXF 36 – 200 / 7000

Reference current with current transformer length = 0 mm, oil temperature = 90 °C and air temperature = 70 °C (bus duct), frequency = 50 Hz

Rated lightning impulse withstand voltage (BIL) [kV]

Rated voltage [kV]

R = RIP insulation | T = transformer application | X = length of oil side part | F = (Freiluft in German) air side

9.1. Marking plate

ABB Switzerland Ltd, Micafil T y p e : R T XF 3 6 – 2 0 0 / 1 1 0 0 0 S - N o . : 2 0 0 9 X X X X X X J a h r : 2 0 0 9 U : 3 6 k V I ≡ 1 Z C D X X X X X X f r : 5 0 / 6 0 H z m : x x x k g

Line 1: name of manufacture, manufacture logo Line 2: Type of bushing Line 3: series number Line 4: year of production Line 5: system voltage, current diagram number, frequency, weight

10. Disclaimer of warranties and limitation of liability

There are no understandings, agreements representations, or warranties, expressed of implied, including warranties of merchantability of fitness for a particular purpose other than those specifically set out by an existing contract stating the entire obligations of the seller. The contents of the document shall not become part of or modify any prior or existing agreement, commitment, or relationship. The information, recommendations, description and safety notations in this document are based on our experience and judgment. This information should not be considered to be all-inclusive of covering all contingencies. If further information is required, ABB Switzerland Ltd, Micafil should be consulted. No warranties, expressed, or implied, including warranties of fitness a particular purpose or merchantability, or warranties arising from course of dealing or usage of trade, are made regarding the information, recommendations, descriptions and safety notations contained herein. In no event will ABB Switzerland Ltd, Micafil be responsible to the user in contract, in tort (including negligence), strict liability or otherwise for any special, indirect, incidental or consequential damage or loss whatsoever including but not limited to damage to or loss or use equipment, plant or power system, cost of capital, loss of profits or revenues, cost of replacement power, additional expenses in the use of existing power facilities or claims against the user by its customers resulting from the use of the information, recommendations, description, and safety notations contained herein.


11. Annex 11.1. Measuring tap


11.2. Measuring circuit

Messschaltung / Measuring circuit / Circuit de measurement

1

Durchführung Bushing Traversée

Kapazität Hochspannungsleiter-Messbelag C1: Capacity high voltage lead – test tap Capacité conducteur haute tension – prise de mesure

Kapazität Messbelag - Flansch C2: Capacity test tap - flange Capacité prise de mesure - bride

2

Normalkondensator Standardcapacitor CN

Condensateur étalon

3

Schering Brücke Schering bridge Pont du mesure Schering

R3 R4 C4

Brückenelemente Bridge elements Élements du pont de mesure

Nullindikator

N: Null indicator Indicateur de zéro

HLJM 118034 ABB Schweiz AG, Micafil ABB

C1 = CN ⋅ R4 / R3 tan δ = R4 ⋅ 2πf ⋅ C4


Contact us ABB Switzerland Ltd., Micafil Badenerstrasse 780 CH-8048 Zurich, Switzerland Phone +41 (0)58 586 03 33 Fax +41 (0)58 586 03 01 E-Mail [email protected] Web www.abb.ch

ABB Switzerland Ltd, ABB Switz erland Ltd, Micafil ... · ABB Switzerland Ltd, ABB Switz erland Ltd, Micafil Transformer high current bushings HIRIP / Technical guide Technical guide

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