+91 9831823173 / 9830252113
Our experience of transformer designing spanning more than a decade is our strength to
satisfy customer requirement. Our team of well qualified expert engineers & technocrats
has developed optimized designs, which are most reliable and affordable for recent
market scenario. Our design activity confirms to the various standard like
BIS/IEC/BS/ANSI, NEMA. All the drawings are CAD for quick review while getting approval
and thereafter, the final drawings can be submitted on a CD along with a print copy as
required. All aspects of transformer design (Electrical & Mechanical) comprising Losses,
% Impedance, Guaranteed Temperature Rise, Pressure & Vacuum withstand capability etc.
are taken care of in our design development. Further our fault detection, Analysis and
their solutions are gracefully welcomed by many reputed customers with their entire
Transformer windings are designed to meet three fundamental requirements, viz.
mechanical, thermal and electrical. They are cylindrical in shape and are assembled
concentrically. Paper insulated conductors of high conductivity and soft drawn
Electrolytic grade copper is used which comply with the latest Indian as well as
international standards. Windings are made with great care by well experienced skilled
Disc Winding workers in dust free & temperature controlled environment.
Insulation between layers and turns is based upon the electrical and mechanical strength
level. Inter layer cooling ducts (Axial & Radial) are provided to minimize the
temperature gradient between windings and oil, and hence the hot spot temperature is
kept to a minimum. This also ensures that the rate of insulation deterioration is
minimized and high life expectancy is achieved.
Transpositions are made in multiple conductor windings, to ensure uniform current
distributions, minimize circulating currents, decrease eddy current loss and improve the
Multiple conductor layer wound coils are most suitable for low voltage windings of large
power transformers to mitigate high current designs requirement. For High voltage
windings the disc coils with excellent mechanical strength are used to take the stresses
due to voltage level. Special interleaved or shielded construction offers most uniform
voltage distribution despite system transient. Specialized disc winding and inter-leaved
disc windings are used having very high series capacitance giving a very good impulse
For better short circuit withstand ability under fault conditions, would coils are
pressed, clamped and dried in oven prior to impregnation in oil. Cooling ducts formed
with rigid, high density spacers and horizontal and vertical ducts are provided to save
The most significant material in a transformer is the core. KVA PROCESS uses high quality
Cold Rolled Grain Oriented Magnetic Silicon Steel to ensure optimum losses and most
efficient working of the Transformer. The type of magnetic steel is chosen according to
the desired loss level. The laminations are cut geometrically to ensure optimum flow of
magnetic flux and minimum air gap between the joint of two consecutive sheets. The
supporting structures and clamping devices of the core contribute to the compactness of
the design and also ensure low sound levels.
The core is designed with safe flux density to minimize core loss and magnetizing
current. But-lap, miter or step-lap-miter construction is chosen based on the
application and core-loss requirements.
Laminations are burr free fully annealed with low Loss and very thin between 0.23 mm and
0.30 mm, varying no more than + 0.05 mm in length for lowest sound level and excitation
currents. Each lamination is covered with a high-resistance, inorganic coating to reduce
The Laminations are handled with utmost care to preserve magnetic properties. The core is
clamped in a rigid frame with uniform pressure to reduce mechanical effect on
Core is built with Cold Rolled Grain Oriental, low loss silicon steel lamination. Bonded
core design / technique is used to eliminate hole punching and to minimize fixed losses
and Magnetizing current. Use of Hib grade & Laser scribed Laminations and Rigid clamps
significantly reduce vibrations and noise level. Cooling ducts are provided in large
transformers for efficient circulation of oil to keep temperature of core well within
limit without affecting the flux distortion and also in the core suitable insulation
paper are inserted between some laminations for the purpose of reducing eddy currents
and also minimizing magnetic short circuit.
KVA PROCESS uses high electrical grade Precompressed Pressboard & kraft paper, as per IS
: 1576. The insulating papers are routinely checked for high dielectric strength.
Permali wood is also used in top and bottom for mechanical strength
L.V. Windings are normally placed near core over insulating cylinder and oil ducts. HV
windings are assembled co-axially with respected to L.V. Spacers between coils are 'T'
shaped for added firmness. Coils are assembled with best insulating materials and are
adequately clamped. The winding is rigidly supported by a common spacer ring of
densified wood at the top and bottom for precise alignment. Well profiled angled rings
are placed between LV & HV windings to reduce voltage stress level. The ends & tapping
leads of all windings are connected by special extra flexible, insulated copper cables
which are rigidly braced in position.
Coil design and quality are keys to transformer efficiency and longevity. KVA Process
design coils specially for each application. We use thermally upgraded paper for longest
All our tanks are fabricated with high grade tested mild steel. The design of the tanks
incorporated adequate wall and base thickness so as to withstand the pressure build up
in the tank.
Protection of active part in transformer is very important. While achieving the optimized
size of transformer to suit the site condition for installation. The main role of the
tank is to protect the active part and tank is manufacture to have sufficient strengths
to withstand internal & external faults that may occur during operation. Tanks are
fabricated from low carbon M.S. Sheet of best quality proceeds by qualified welders. The
tank is designed to withstand vacuum and pressure test as per Indian/International
standards. A robust skid under base is provided, and guide bars are located inside the
tank to securely fix the core and windings assembly in position, and to prevent any
movement during transportation.
Each transformer tank is tested for leakage by filling them with oil and keeping then
under pressure of 0.5 KG / Cm2 or above for several hours. With this test even minute
leaks are detected.
The transformer while in service gets heated and Electrical Losses like Load Loss & No
Load Loss which must be dissipated to avoid the exceeding the Temperature Rise limit
specified by Customers. To achieve Temperature Rise well within limit, a suitable
cooling method is be adopted.
Generally, the cooling method suitable for the transformer is determined by the customer
after due consideration of transformer capacity and the circumstances at the
installation site. KVA PROCESS can design and manufacture transformer with various types
of cooling systems according to the customer's requirement.
The insulating oil used is low viscosity with good resistance to oxidation and formation
of sludge and acids. Moisture content, dielectric strength etc is determined and
certified by conduct relevant tested as per IS : 335/1993. Generally we use “TRANSOL”
brand, 'SAVITA' make EHV grade oil.
Our testing lab is fully equipped with digital and computerised testing meters and
accessories to conduct all routine tests as per ISS & IEC upto 25 MVA and upto 132 KV
Voltage grade. The list of routine test are as follows :