HERMETICALLY SEALED TRANSFORMER
Hermetically sealed transformer is a transformer design which has no conservator. Here the dielectric insulating fluid in the transformer tank is completely sealed and is in zero contact to the atmosphere.
This type of transformer is used in applications where the transformer is to be installed in harsh climatic conditions (smoke, pollution, dusty environment,etc.) or if the transformer is KNAN cooling type.
The design avoids air in the transformer tank thereby avoiding sledging and oxidation of the dielectric fluid.
Hence it would be safe to say that these transformers need no maintenance of the dielectric insulating fluid (usually Natural Ester / Synthe c Ester Oil). Normally these type of transformers are accommodated by devices that measure heat related volume variations. Gas cushion is used to compensate the volume variation due to heat. Normally the gas is nitrogen.
Features:
- Rated Power (kVA): from 100 kVA to 250 kVA.
- Rated Voltages (kV): Up to 36 kV and Dual Voltages
- Tank Type: Hermetically Sealed (Closed Atmosphere)
- Frequency (Hz): 50 Hz or 60 Hz
- Cooling: ONAN / KNAN
- Standard: IEC /IS
- Conductor Material: Electrolytic Copper or Electrolytic Aluminum
- Phase Number: Three Phases or Single Phase
- Geographical Conditions : (Altitude, Humidity, Negative Ambient Temperature
etc.) - Accessories: Ra ng Plate, Oil Level Indicator, Dial Type Thermometer, Compact Protec on Relay (R.I.S.), Wheels.
- Class K—Transformers with Natural or synthetic ester oil Transformers
Application:
- Industry, commercial building
- Solar / Wind
- Distribution
- Converters
- Step up
- Transformer for Photovoltaic Systems
- Starting Motor
Cast Resin Dry Type Transformer ( CRT)
Cast resin dry type transformer (CRT) is used in the high moisture prone areas. It is because of its primary and secondary winding are encapsulated with epoxy resin.
Vacuum Pressure Impregnated Transformer (VPI)
This type of transformer is made with mini-mum flammable material as insulation of windings. The windings of this transformer are made in strip in a continuous layer.