Manufacturers of High voltage Instrument Transformers

Outdoor OIP Insulated Voltage Transformers up to 72.5 kV

Features

1. The main insulation is Oil Impregnated Paper (OIP) which is proven and accepted insulation system for high voltage equipment since many years.
2. EHV Grade napthene based mineral oil free from inhibitors is used. This oil has excellent chemical and electrical ageing properties and also is resistant against oxidation.
3. The transformers are truly hermetically sealed by adopting the fully oil filled design. Stainless Steel diaphragm is used for oil volume compensation due to temperature variations.
4. The design philosophy is identical for transformers from 12 kV to 72.5 kV. Further, the product features and general engineering used for manufacturing are same for all the above range of products achieving highest standardization resulting in to consistent product quality.
5. The top tank is deep drawn and has no joint. The major joint is welded (tank-diaphragm) and the total number of joints is kept minimum to qualify true hermetic sealing.
6. All sealing are done with moulded Nitrile Rubber gaskets / O rings which are placed in properly dimensioned grooves and are prevented from direct exposure to atmosphere.
7. Primary terminals are single piece integral components which cannot be un-tightened or removed from outside.
8.  Primary winding is done in trapezoidal fashion with continuous reduction of turns to ensure mechanical stability and also high strength against impulse voltages. High quality kraft paper is used as inter-layer insulation and is judiciously applied to obtain optimum performance
9. Porcelain insulator is cemented with metallic flanges for uniform stress distribution.
10. Secondary terminals are brought down through a single sealing epoxy resin cast mono-block and are terminated on removable or replaceable terminal stations. The handling on the secondary terminals does not affect sealing.
11. The major insulation (OIP) is capacitively graded for uniform electric field distribution and for highest strength against over voltages and impulse voltages / switching surges.
12. The major insulation is dried and de-gassed under controlled temperature and vacuum until the desired insulation properties are obtained
13. The transformer oil is filtered in our oil filtration plant and after getting desired insulation properties, the oil is filled in the product under vacuum at a constant steady flow rate through a non-return valve at the bottom of the transformer.
14. Stainless steel diaphragm is tested for a life of minimum 25 years.
15. The top tank cover is designed without flat flange and ensures rain water /dust does not accumulate.
16. All metal parts are painted in-house. The painting scheme is shot blasting, zinc spraying, followed by two coats of epoxy based zinc rich primer with a top coat of polyurethane paint of desired shade.
17. All exposed hardware is of stainless steel.
18. VTs can be designed to international standards IEC, BS, ANSI(IEEE) etc.

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1. The main insulation is non-aging Cyclo-aliphatic Resin which is a proven outdoor insulating material since last 30 years.
2. The Voltage transformer is encapsulated in the resin in a single process which is done under controlled temperature and vacuum.
3. The transformer is very compact
4. It requires practically no maintenance.
5. Primary winding is done in trapezoidal fashion with continuous reduction of turns to ensure mechanical stability and also high strength against impulse voltages. High quality kraft paper is used as inter-layer insulation and is judiciously applied to obtain optimum performance. The coil is dried, and impregnated with low viscosity resin under vacuum prior to the final encapsulation.
6. All metal parts are painted in-house. The painting scheme is shot blasting, zinc spraying, followed by two coats of epoxy based zinc rich primer with a top coat of polyurethane paint of desired shade.
7. All exposed hardware is of stainless steel.
8. Transformer is designed and processed to obtain partial discharge free performance.
9. VTs can be designed to international standards IEC, BS, ANSI(IEEE) etc.

Please get in touch for more details.