Direct measurement of Voltage in high voltage system is not possible because of insulation problem of measuring instruments. It is also not possible to use voltage through the system directly for protection purpose due to its high value & high insulation problem. In such conditions voltage transformers are used.
Basic Functions Of Voltage Tranformer :
- To reduce the line voltage to a value which is suitable for standard measuring instruments, relays etc.
- To isolate the Measuring Instruments, Meters, Relays etc. from high voltage side of an installation.
- To sense abnormalities in Voltage & give Voltage signals to protective relays to isolate the defective system.
The transformers are oil filled, assembled in M.S.Tanks & Chambers together with suitable Porcelain Bushing. High quality C.R.G.O. Silicon Steel is used in the transformer. High quality kraft & crepe insulating paper is used to build up main insulation. Semiconducting shield is used to give linear distribution of Electrical stress along the length of the bushing. Filtered & de-aerated EHV grade oil is filled in VTs while VT is under vacuum. To seal it, the space left for expansion on the top is filled with dry & pure Nitrogen through non returnable valve at pre-determined pressure. Design incorporating Stainless Steel Bellows instead of Nitrogen cushioning is also available.
Electrical Specifications :
- TYPE : Single Pole Insulated & Double Pole Insulated.
- OPERATING VOLTAGE : Single Pole Insulated 1 lkV, 22kV, 33kV, 66kV, 11OkV, 132 kV, 220kV.
- SECONDARY VOLTAGE :110V, 110V~3,,,,,, 110V/ 3 (others on request)
- BURDEN : 50VA,100VA,150VA,200VA (others on request)
- ACCURACY :0.2, 0.5, 1.0, 3.0, 3P,6P.
- FREQUENCY : 50 Hz.
- OPERATING TEMP :-10°Cto40°C
- SYSTEM CONDITION :Earthed, Unearthed.
- CONFORMS TO : IEC186,IEC60044-2,IS3156.
Ordering Information :
While ordering mention all the Electrical Specification required.