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Liquid Immersed
Transformers

What is Liquid Immersed Transformer?

A Liquid Immersed Transformer is a type of electrical transformer that uses liquids such as Mineral or Silicon Oil, or Ester (Synthetic / Natural) Fluids as a cooling and insulating medium. The liquid serves two primary purposes: it insulates the internal components (windings and core) and supports the heat dissipation of the heat generated during operation.

These transformers are widely used in power generation, transmission, and distribution systems to step up or step down voltage levels efficiently.

Types of Liquid-Immersed Transformers
Manufactured by Danish Power

Power Generation
Power Generation
  • Steps up voltage for efficient transmission from power plants, be it thermal, nuclear, or any type of renewable sources such as Solar, Wind, Hydro, Biomass, etc.
  • Ratings start from 2 MVA 11 kV and go upto 100 MVA 245 kV.
  • Depending on the type of generation, these transformers are often called Generator Transformers, Inverter Duty Transformers (for Solar), Wind Turbine Generator Transformers, etc.
Transmission Networks
Transmission Networks
  • Used in substations mainly to step down voltage.
  • Ratings start from 5 MVA 33 kV to 100 MVA 245 kV.
Distribution Networks
Distribution Networks
  • Used for bringing the power further stepped down to the actual point of consumption.
  • Ratings start from 250 kVA 11 kV to 5000 kVA 33 kV.

Danish Power's World-Class Liquid Immersed Transformers, Engineered for Excellence!

The R&D team of experts continuously work on developing one of the most advanced designs to withstand short circuits. Oil Immersed transformers are crafted with the utmost care in workmanship & selection of quality raw materials, ensuring a long and maintenance-free life.

Features:

  • Robust design to take care of frequent short circuits.
  • Manufactured with prime CRGO using step-lap design for low losses along with availability of Hydraulic Core Lifting Facility.
  • Windings made up of Copper or Aluminum manufactured using Strip (PICC/AC or CTC) / Wire / Foil.
  • Step up and Step down transformers offered.
  • Low noise levels.
  • Various rating Type-Tested for Short-Circuit, Impulse Voltage Withstand & Temperature Rise Tests at KEMA, CPRI & ERDA.

Technical Specifications

Ratings 3 phase upto 245 kV 100 MVA.
Frequency 50/60 Hz
Applicable Standards Latest versions of International & Indian Standards such as IEEE, IS:1180, IS:2026, IEC:60076, ANSI 57, BS, SANS 680
Class of Insulation A/B/E
Cooling Typically as ONAN (Oil Natural Air Natural) but also available with other High Capacity Cooling options such as ONAF (Oil Natural Air Force), OFAF (Oil Forced Air Forced), OFWF (Oil Forced Water Forced), KNAN or others upon request.
Vector Group Any as per customer requirement like Dyn11, Yzn11, Dd0, etc.
Insulating Fluid Mineral Oil / Silicon Oil, both inhibited & uninhibited, as per IS/IEC/ANSI/BS/SANS Standards. Biodegradable Natural or Synthetic Ester Filled Transformers also offered.
Standard Accessories As per customer specifications.

Options

Radiators

Corrugated Fin Radiators or Pressed Steel Radiators

Conservator Type

Sealed type or Breathing type with Conservator

Protection Type

CSP (Completely Self-Protected) Type. DGPT2/ DMCR protection device for sealed type transformers

Tap Changer

Off Circuit Tap Changer with tapping range of 5, 7 or 9 positions OR On Load Tap Changer with an Automatic Voltage Regulating & Remote Tap Change Control Panel (AVR cum RTCC Panel) with tapping range from 7 to 27 positions

Termination

Porcelain / Cycloaliphatic / Epoxy / Touch Proof Plug-in type Bushings with option of Cable Box / Bus Duct

Temperature Sensors

RTD Temperature Sensors (analog/ digital) for alarm & trip, with options of 4-20 mA output or RS-485 for SCADA compatibility

Breathers

Options are available with long life maintenance free Breathers

Tanks

Usually made of Mild Steel but also available of Stainless Steel

Paint Options

Flow Painting (PU Paint), Powder Coating or Metallizing / Galvanization suitable for C3, C4, & C5 Harsh Environments as well.