EHV Power Transformers upto 500 MVA, 500 KV Class
In Technical Collaboration with M/s. Daihen Corporation, Japan Routine and type tested upto 500 MVA Bank (of 3 single phases) 400/220/33 kV Transformer and 315 MVA ( 3 phase) 400/220/33 kV Auto Transformer & short Circuit Tested Successfully on 50 MVA, 132/66 kV and 35 MVA, 220/11 kV.

PROFILE OF TECHNICAL COLLABORATOR (DAIHEN)
Recipient of Deming Prize Medal awarded in 1987.
Supplying EHV Transformers up to 500 MVA, 500 kV across the Globe for the last 3 decades.

EHV Power Transformer
With a proven track record of more than three decades into manufacturing of Distribution and Power Transformers, Vijai now has a fully integrated state-of-the art manufacturing facility at Rudraram, to cater to the huge potential of the EHV Power Transformer market globally.

• GEORG CNC Cut-to Length Line for step lap cores.
• Air conditioned winding shop and core coil assembly shop.
• Stabilizing autoclave for simultaneous application of pressure,vaccum & temperature.
• Isostatic pressing system for dimensional accuracy.
• Vapour phase drying oven with Vaccum levels less than 0.1 millibar.
• EHV Testing Laboratory equipped with state of the art test facilities to test transformers upto 500kV as per international standards.

STATE OF ART MANUFACTURING FACILITIES
GEORG CNC Core cutting Machine
The Automatic cut-to-length line of GEORG offers stress free laminations without burrs for fully aligned core building. The Step- lap joints at the core corners ensure a streamlined magnetic flux path.
Salient Points:
1) Burr level less than 10 Microns.
2) Lamination Width upto 1000 mm.

Core Assembly
Core assembly is done on a 150 tonne hydraulically controlled, core lifting platform to maintain the accuracy of dimensions and integrity of core assembly.
Automated assembly allows dimensional accuracy, reduces core loss building factor and improves productivity.
Salient Points:
The core is assembled with a bolt less construction.

FULLY AIR - CONDITIONED WINDING SHOP
The Winding shop is equipped with several sets of newly developed large horizontal and vertical winding machines which apply an even, constant pressure in both axial and radial directions depending on the number and size of wires to be wound and the thickness of the insulating material during the winding operation.
Coil winding is performed in the Air-conditioned shop in order to maintain superior quality of the product.

COIL STABILIZING OVEN
The Coil is stabilized under pressure while being heated at proper temperature, vaccum and Isostatic pressing in the coil stabilization treatment chamber to acquire enough strength to withstand the electro-magnetic force under severe short circuit condition.
Coil winding and Coil assembly are carried out in a completely Air-conditioned environment. Moreover, cranes are provided with dust proof devices to prevent dust from falling. The shop floor is made with ferro-concrete epoxy flooring to ensure dust free atmosphere.
The whole workshop is designed with the utmost care to prevent dust infiltration.
To prevent insulation materials from absorbing moisture, the air-conditioning equipment is used all the year round. In addition drying treatment is performed in the coil stabilizing oven to ensure higher reliability of transformer insulation, dimensional stability and rigidity which are essential for ensuring enough mechanical withstand strength | against electro dynamic forces under system short circuit conditions. Each coil is individually stabilized and coil assembly is carried out in the same shop and is once again treated in the oven before proceeding for core coil assembly.

Air conditioned dust free shop for core coil assembly
The Active Part Assembly Shop is designed to be maintained at a constant temperature and low humidity. Care is taken to prevent the entry of dust through the entire course of production up to the drying of the core and coil assembly.

Indigenously developed vapour phase drying oven
Vapour Phase drying is carried out in our unique indigenously developed vapour phase drying oven to ensure high reliability in the dryness of transformer insulation.

EHV POWER TRANSFORMER TESTING LABORATORY
60X30X35M height testing laboratory suitable to test transformer up to 765 kV class.
Impulse Generator
2400 KVp, 240 KJ Impulse Test system having state of art High Impulse Analysing system(HIAS) for recording and analyzing the Impulse voltage and Neutral Current Wave shapes.
Motor generator sets
1.75 MVA (175 Hz) and 7.5 MVA (50 Hz) Motor generator set, 60 MVAr Capacitor Bank and associated test system with digital temperature recorder to feed the power during induced overvoitage and heat run tests respectively.
All tests as per IEC, BS, IS and other international standards can be conducted in the in- house test lab upto765kV.

3D view of EHV Power Transformer

With a fusion of technical expertise ranging over 30 years and new talents absorbed into the organization, Vijai has an established design wing to cater to a wide range of customized designs for EHV Power Transformer. Vijai's advanced systems used in the design and manufacturing process in tandem with stringent quality measures and monitoring systems, contributes to a speedy response meeting the customers requirements.

Thus Vijai ensures the customer with superior and reliable quality of the product with product improvement as its continuous process.