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HT & LT Transformer

PROFILE


Started in the year 2000, with the motto of bringing Global Standards to manufacture transformers in the range of 11 to 132 kV.

PRODUCT RANGE

  • Power Transformers 20,000 kVA of 132 kV class.
  • Distribution Transformers 250 kVA and above.
  • Furnace Transformers.
  • Rectifier Transformers.
  • Booster Transformers
  • Earthing Transformers.
  • Mining Transformers.
  • Windmill Transformers.

QUALITY ASSURANCE OF MATERIALS

All in coming materials are inspected to confirm to the Company-National standards.

QUALITY ASSURANCE OF PROCESS

At every stage of manufacture, transformer is inspected to confirm to company quality assurance program.

During Manufacturing Process

  • Ratio and phase angle error test before connections are brazed.
  • Vector group test before connections are brazed.
  • Magnetic balance.

PRESSURE TEST

Before dispatch all transformers are tested at specified pressure to ensure leak proof joints.

ROUTINE TESTS

(As per IS 2026:1997)
Ratio : Winding resistance / OLTC M.B.B Contacts
checking
Polarity : Open circuit test
Phase angle error : Short circuit & impudence test
B.D.V of oil : Separate source voltage test
I.R values : Induced over voltage test
Polarization Index : Vector group test
Dielectric discharge : Zero sequence Impedance test

SPECIAL TESTS

All the design are tested for heat run test. In house heat run test facility available up to 20,000 kVA. Oil test facilities like tan delta, Resistivity, Acidity, PPM and suspended particles are available in house.

DESIGN

Transformer is designed for low losses. Selection of core material with low specific losses and proper selection of conductor dimensions meet the goals.
Tap turns are distributed along the length instead of lumping at the center of winding to minimize short circuit forces.
Cooling ducts are dimensioned to limit hot spot temperature of windings. At the same time winding spacers/blocks are dimensioned to limit the stresses on windings due to short circuit forces.

PROCESSING

HV and LV Windings are dried by heating and pressed by hydraulic jacks to predetermined short circuit forces.

DRYING

Core and coil assembly is dried by heating under vacuum in vacuum-drying oven controlled by PLC circuit. After the assembly is dry, it is taken out of oven, windings are then clamped tight. The assembly is housed into its tank and dry transformer oil is filled into it under vacuum drying oven.

OIL PROCESSING

Oil is filtered through ultra high Vacuum Filter Machine for limiting the moisture content to less than 5PPM.

FABRICATION

Tank, cable boxes and core clamps are manufactured from weldable quality steel confirming to Indian standards.
Tanks are designed to withstand the hydraulic pressure test prescribed in CBIP specifications. Clamps are designed to with stand forces transmitted on to them by short circuit of windings.
Cable boxes are designed to facilitate easy connection of cables.

© 2005 - Donvey Power Control Systems Pvt. Ltd, Web Services by Paradox Technologies Pvt. Ltd.