A VIETNAMESE MEMBER OF A WORLD - WIDE FAMILY

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2 A VIETNAMESE MEMBER OF A WORLD - WIDE FAMILY ABB Ltd. ABB Ltd. was originally a Joint Venture Company, ABB Transformers Ltd., between the Vietnamese transformers manufacturer CTBT, affiliated with Ministry of Industry, and the international electrotechnical group ABB. It has been in operation since 1 September CTBT's local experience and knowledge combined with ABB's technical and managerial expertise will lift the transformer quality up to an international standard and bring Vietnam into the family of developed countries within transformer engineering. ABB transformers factory located in Tanh Tri, just outside Hanoi. Now it is producing distribution transformers up to 16MVA, 35kV. In 1999, with the addition of the power transformers division, the factory started manufacturing power transformers up to 100MVA and 110kV 2

3 Saving energy is valuable Decades of economy Transformers are capital goods with In order to determine the most It is more difficult to evaluate load a life expectancy for decades. For economical design for the losses because they increase and this reason the buyer should not only respective application it is important decrease quadraticly with the load. consider the initial costs of the to know which capitalized value The lower limit of the load-loss transformer but also the estimated results from determined losses. This evaluation, however, is easily maintenance costs as well as the value can then be set in relation to ca lc ul at ed be ca us e on ly th e Costs of no-load losses of the iron the initial cost. Higher initial costs constant factor, determined by the cor e an d lo ad l oss es o f th e caused by increased amount of core energy cost, is taken into windings. steel and winding materials result in consideration a price range of USD lower operating costs. from 0.56 to 1,3 per watt. The Evaluating no-load losses is average value is from approx. USD relatively simple because they per watt. accrue at a constant rate during the Shows a model evaluation based on total operating time of 8760 hours various realistic assumptions. It annually. The values fluctuate proves that it pays to use ABB oil between. USD 4-10 per watt, transformers with reduced losses. depending on local. The average In the event of special operating Evaluated load losses price is approx. USD 6 per watt. But conditions and electricity costs one it must be evaluated for each must deviate from the values given country transformers with reduced in the selection tables. Optimized no-load losses are recommendable, designs which meet individual capitalized value 0 P/P N (fixed energy costs) evaluated No-load losses Initial costs 0,2 0,4 0,6 0,8 1,0 1,2 Principle diagramm (400 kva) capitalized value vs. P/P characteristic N ABB oil transformers are manufactured of only the highest quality materials and by the most modern and reliable methods. Thus the transformers are of a high availability and require small maintenance. And therefore hermetically sealed transformers is standard for all. ABB transformers in the range from 31,5, kva to 2000 kva on request. too, because therewith is associated a reduction of noise emission. requirements are available and are delivered on request. Example of a capitalized value comparison for 400 kva Initial costs KA No - load losses Po Load losses Pk Loss evaluation no - load losses Loss evaluation load losses KPo = 6 USD/watt x Po KPk = 0,56 USD/watt x Pk Variant I Variant II Variant III Variant IV USD 6 per watt USD 0,56 per watt PO Pk KA KPo KPK Totai in W W USD USD USD USD Stacking Core

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5 Factory ABB Ltd produce transformers and other electrotechnical prod- ucts in the previous CTBT factory in Thanh Tri, outside Hanoi. The distribution transformer factory has been totally renovated, lifting capacity is increased and working environment improved. After renovation the buildings are of a standard comparable with other ABB factories around the world. Almost all present machinery and equipment has been replaced by imported ones. This is necessary The ABB transformers are designed to withstand a direct short circuit across the terminals. Short circuit tests to demonstrate the transformers abilities to withstand thermal and mechani- cal stress during short circuits have successfully been performed in many different laboratories in accordance with IEC procedure. to meet our requirements for international quality and productivity. Special attention is paid to test equipment and facilities giving customers reliable testing and quality control of the products they buy from us. Standards. The ABB distribution transformers are produced and tested accord- ing to IEC Publication 76. General Design. Product and design engineering is the well - proven and international recognized ABB technology used world-wide. The transformers are three-phase, oil immersed with ONAN cooling, for indoor and outdoor installation. They are available in ratings from 31,5 kva to kva and maximum voltage 36 kv. The transformers can either be hermetically sealed or free breathing with conservator. The special winding design gives a uniform impulse voltage distribu- tion, and guarantees ability to withstand lightning overvoltages. The ABB transformers can be overloaded in accordance with IEC Publication 354 "Loading guide for oil immersed transform- ers. 5

6 Optimum core The core Consists of cold-rolled, grainoriented magnetic sheets of the highest quality. The most advantageous transfer of the magnetic flux from legs to yoke is achieved by overlapping the opposing - joints on neighbour sheets. In some cases they are staggered several times. The cutting angle generally 0 amounts to 45 These provisions reduce the values of no-load losses and no-load currents as well as of the noise and increases the mechanical solidity. The cutting line with Computer controled Cross-sections of yokes and legs are nearly round due to the staggered width of the sheets. The core are cut in an automatic cut-to-length equipment. The legs and the lower yoke are laid in a special device. After mounting the coils the insertion of the upper yoke follows. Stacking Core 6

7 Reliable windings For almost two decades an impulsevoltage and short-circuit proof combination of LV foil winding and HV layer winding has proved in ABB distribution transformers. For economic reasons electrolytic copper is used as conductor material. LV foil winding Transformers with rating 160 kva and higher have low voltage winding made of copper foil which reduces load losses and eliminates axial forces during short circuits, thus increasing the mechanical strength of the transformers dramatically. In transformers with lower ratings where stray losses and mechanical stress during short-circuit are less critical, conductors of paper insulated copper wire are used. HV layer winding Making a LV foil wingding The high voltage winding is of the multilayer type, which ensures a uniform voltage distribution of lightning overvoltages, resulting in improved dielectric strength. The conductors are made of copper and are either enameled or paper insulated. A special type of epoxy diamond dotted Kraft paper with high mechanical and electric strength is used as insulation between layers. Connections from the coil taps to the bushings and to the tap-changer are made by contact crimped copper leads. Making a HV layer wingding 7

8 Top quality materials The tanks. The tanks are made of corrugated steel plates. The tanks are of the hermetically sealed type, which totally prevents moisture from the air being absorbed in the oil thus increasing long term dielectric strength and reducing oxidation of the oil the cooling fins are designed to take up the expansion during operation. Tanks and covers are sand-blasted phosphated and electrostatically painted with a polyester powder paint. This is resistant to atmospheric aging and UV light, giving an excellent and durable protection against corrosion. Foiling the tank fins The cover Is bolted to the tank and standardized bushings are fixed to the cover by studs. The conservator depend on request of customer for over 2000 kva is equipped with a magnetic oil level indicator and a filling/venting plug. Corrosion protection Corrosion protection Makes an important quality feature of ABB transformers. To the cleaned and prepared surface an active primer. The applied coats are forming a specific coordinated system tested by wellknown power suppliers. 8

9 Reliable processing The core-coil assembly Occurs in a production line in which the cores are carried to the mounting stations. After the HV and LV coils are mounted and centred the upper yoke is stacked and the core-coil clam-ping device is fixed. The cover is also bolted to the upper clamping. The HV winding leads are insulated with paper tubings and brazed I Crimped to the connection of the bushings resp of the tap changer. The HV leads are insulated against the upper clampings by a press board panel, while an additional panel fixes the position of the Leads. Drying and Oil Filling All transformers are dried by elevated temperature, and then filled under vacuum with dried and degassed oil. By this process the risk for reduced dielectric strength due to moisture and air inclusions in the insulation is eliminated. All transformers are shipped with oil and shall not be opened for inspection after they have left the factory. The mineral oil used in the transformers complies with IEC Publication 296 Assembling the windings Assembling the electric part Vacuum drying Mouting the untanking part 9

10 Accessories for ABB distribution transfomers All demands met Tap changers can provide transformers with The trip contact is activated in The standard voltage regulation voltage switching between case of acute damages. All range is ± 2x2.5% but other ranges present distribution voltage and transformers from 1000 kva and can be supplied upon request. future 20kV network greater can be equipped Each transformer is equipped with Buchholtz relays additionally with a Buchholtz a five position off-load tap Protect the transformer against oil relays without problem after the changer. The tap changer must loss and the results of thermal adaptor has been removed. only be operated when the overload of the insulating Winding Temperature Indicator transformer is de-energized. We materials. The alarm contact in the Are used for indication of the are only using tap changer from double-float design indicates tem por ary oil tem per atu re. the leading suppliers in the world. degree of the oil level as well as Contacts for alarm and trip signals By using tap changers and special al re ad y l it le ge me ra ti on of ca n b e a dd ed as ov er lo ad high voltage winding design, we decomposition gases. protector. Tap changer Oil level indicator for Transformer with conservator Oil level indicator for hermetical sealed type Oil level indicator with contacts Double-float Buchholtz Relays Winding Temperature indicator 10

11 Evidence of quality By the routine test All transformers are tested according to IEC Publication 76, specifying following routine tests: -Ratio polarity and vector group measurement. -Measurement of winding resistance -Measurement of load losses and impedance voltage. -Measurement of no load losses and no load current. -Induced overvoltage withstand test. -Separate source voltage withstand. On request the following type tests canbe conducted: -Heat run test. -Noise measurement. The temperature rise Of the windings is measured by a type test. At that the average winding temperature in accordance with insulation class A must not exceed a value of above ambient temperature. The short-circuit resistance Is verified by special tests and, on request of the Noise measuring customer. Done by well-known test laboratories. Many years of test experience and good operating experien of the customers have confirmed the efficiency The noise levels Are less than those permitted by IEC - 76 The impulse-voltage resistance of components and of complete transformers is verified in the test laboratory by type tests and random sample tests. Testing room 11

12 Custom made for your requirement ABB distribution transformers are = 36 kv on the HV winding, Um = well as supplementary customer manufactured acc. to IEC-76 and 0,4 kv on the LV winding, as well needs for accessories and the up-to-date "Technical terms of as a frequency Of 50 Hz and connections. Maintanance of delivery of transformers". These continuous operation with natural hermetically sealed transformers rules pertain to oil-filled threeis less frequent because the cooling. phase transformers with a rated The combination of series parts power of kva; a and design groups enables to insulation does not come in maximum operating voltage of Um meet international regulations as contact with the ambient air. 12

13 After - sales service Machine - made repair/overhaul of transformers of different producers Main points of repair / overhaul. - Cleaning and corrosion removal - Arrival test acc. to IEC-76 and state recording. - Waste oil disposal. - Dismantling of the transformer. - Cleaning, checking, and fault removing on the core-coil assembly. - Revision of the tap-changer. - Stove drying of the core-oil assembly. - Mounting the transformers with change of all seals. - New-oil filling and evacuation of the transformer. - Final test with test report acc. to IEC-76 and fixing an overhaul rating plate. - Surface treatment by flooding process. - Pressure test for tightness. 13

14 After - sales service Additional services - Manufacture of new tanks and adequate reconstruction. - Manufacture of new conservators and their mounting. - Manufacture of new windings (for own products) at electric failures depending on the year of construction. - Reconstruction of the terminal technique to IEC version, all variants of plug-in technique. - Reconstruction to the desired equipment, for example magnetic oil-level gauge. Buchholtz relay, dial thermometer, oil level Indicator for hermetic design and so on. l Repair on site: Sealing works change of accessories, adjusting of oil level, exchanging of different bushing systems (plug-in technique) l Transport: Taking over of all transport services with customers' requirements l Analyses: Oil check for PCB-content, breakdown response and tang-δ-measurement, winding test expert opinion on transformers fault reports. l Replacement supply: Providing of substitute transformers during the period of repair (lf present on stock) to replace damaged one. l Spare-part supply: Holding instock accessories bushings, seals and so on. l Machine-made repair / overhaul of transformers of different producers l Documentation: Holding available of test records also for transformers already delivered acc. to IEC-76, service instructions prospectures. Your special inquiries for all further problems of repair and service please address to our after-sales-service office 14

15 ABB IN VIETNAM ISO 9001:2000 UKAS QUALITY MANAGEMENT HANOI ABB HEAD OFFICE ABB INDUSTRY CO.,LTD TCVN :1997 ABB LTD. IE C 7 6 : WE ARE AT YOUR DISPOSAL Our entire programme We produce: - Oil transformers up to 63 MVA, service voltage up to kv in accordance with all the relevant standards and in special designs. - On-load regulating transformers with on-load tap-changer. - Pole-mounted transformers. - Earthing transformers. - Dry type transformers, in insulation class F for power station applications. - Rectifier and furnace transformers BRANCH OFFICE DA NANG Repairs: Transformers and electrical machinery of all kinds and makes up to 63 MVA; production of complex replacement windings; acceptance of PCB-filled transformers for disposal. HO CHI MINH CITY BRANCH OFFICE ABB Ltd. DISTRIBUTION TRANSFORMERS DIVISION Milestone No 9, National Highway No1 Hoang Liet, Thanh Tri, Hanoi, Vietnam Telephone: (+84.4) Fax: (+84.4)