Power Transformer 2 windings & 3 windings

Auto Transformer

Inter - bus transformer

Generating transformer

Unit auxiliary transformer

single phase transformer

Shunt Reactor

* Rated Power 3 - 500 MVA
* Rated Voltage up to 550 kV

Coil Winding

Coil winding is performed in the dust-proof air-conditioned and humidity-controlled room in order to raise the quality of product. The transformer coils are made of electrolytic copper strip conductors with rectangular cross-section and rounded corners which are wrapped with several layers of kraft paper. Several winding methods are employed to meet the requirement of the customers.

Insulation Production

Insulations for the transformer are produced and stocked in the air-conditioned room in order to prevent insulation material from absorbing moisture.

Coil Stabilizing Treatment

The coil is pressurized while being heated at the proper temperature for 36~48 hours in the coil stabilizing treatment chamber to acquire enough strength to withstand the electromagnetic force under severe short circuit condition.

Core Assembly

The high quality silicon steel strips are cut by modern automatic cutting machine into sheets. These sheets are stacked horizontally on the core raising table, each corner being carefully miter-jointed to make the best use of properties of the core material. The stacked core is clamped to the table and is gradually raised to the upright position together with the table to avoid undue mechanical stress in the core, so that high quality of the core can be assured.

Wiring Connection

The connection between the winding ends and the bushings, as well as between the winding and the tap changer, are made of copper cables insulated by wrapping with Kraft paper. All joints between conductors are tightly well-connected with smooth surface to reduce the electric stress.

Tank-Fabrication

Tank parts are carefully welded both inside and outside and are thoroughly checked for oil leakage when the tank is completed. These tanks can withstand a full vacuum and also the proper internal pressure test. Both inside and outside surfaces of tank are shotblasted thoroughly before being coated with the rust proof primer and final painting.

Radiator Production

High quality panel type radiators are produced by automatic line consisting of panel welding, molding press, assembling and painting.

Shipment

During transportation, bushings and other accessories are removed from the main tank and the transformer oil is replaced by dry nitrogen gas to reduce weight.

Core Production

• Automatic silicon steel sheet cutting machine
• Core stacking and core raising table

Fig.1 : Core Cutting Machine



Winding and its Insulation Production

• Winding machine in air-conditioned, humidity control and dust-proof room
• Insulation paper processing machine
• Kraft paper wrapping machine

Fig.2 : Winding Machine



Fig.3 : Kraft paper wrapping machine



Assembling, Drying and Oil Treatment

• Coil stabilizing treatment
• Drying oven
• Vacuum oil purifying equipment
• Vapour phase drying equipment

Fig.4 : Coil Stabilizing Treatment



Fig.5 : Drying oven



Tank Fabrication and Painting

• CNC plasma cutting machine
• NC Band Saw cutting machine
• Plate cutting and bending machine
• NC Pipe bender
• Shotblasting equipment
• Painting booths

Radiator production

• Automatic panel robot welder
• Panel molding press machine
• Semi-automatic panel processing line

Fig.11 : Automatic panel robot welder


Fig 12 : Panel Molding Press Machine

DAIHEN has all facilities to perform all tests normally required by the customers in compliance with existing transformer standards such as ANSI, IEC, BS, JEC and others. Those facilities have capabilities sufficient to test transformer of rated capacity up to 500 MVA and rated voltage up to 300 kV.

Temperature-rise test and impedance test can be carried out under full load conditions, since three phase motor-ganerator 1,000 kVA, capacitor banks 130 MVAR and matching transformers are available for that purpose.

Dielectric tests are carried out with a high frequency generator 1 phase 200 Hz 300 kVA or 3 phase 200 Hz 800 kVA, a high-voltage testing transformer 1 phase 50/60 Hz 460 kV 690 kVA and an impulse voltage generator 1,600 kV 160 kJ in addition, partial discharge can be observed during the dielectric test or prolonged over voltage test.

Analysis of the various gases dissolved in the transformer oil, which can also be performed before and after temperature-rise test and dielectric test, is the most reliable means for the diagnosis of the transformer under operation. By this means even a small discharge or locally heated hot spot can be detected before they may develop to a serious failure.

The testing shop is also provided with a wide range of measuring apparatus to facilitate such tests as noise and characteristics of transformer.

Testing facilities :


Fig.1 : Lightning impulse voltage test systems


Fig.2 : Control desk of Lightning impulse generator


Fig.3 :Transformer loss measuring system


Fig.4 :Control desk of Transformer loss measuring system


Fig.5 : control room


Fig.6 : Testing transformer


Fig.7 : Generator


Fig.8 : Control desk of generator


Fig.9 : Auxiliary transformer


Fig.10 : Capacitor bank

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