Oil Filled Current Transformers

Current transformers are tested in fully equipped testing lab for all routine tests as per IS : 2705, I IEC6004-part 1or other relevant standard as specified by the customer. The CTs are also tested at CPRI for various rating from time to time in approved labs for design validation.
 

TESTING

All Current transformers have special identification number given right from stage one. This will enable us to trace the fault up to root level in case of failures and thus implement the preventive action.

Secondary winding is made first over the toroid with thermal isolation. Insulation of the secondary winding is done in accordance with high voltage requirements. Primary is finally wound over the insulated coil. Surface of the coil is made uni-potential with special tapes. Number of such uni-potential layer depend upon the system voltage. Such layers will relieve the coil from voltage stresses. Secondary leads are brought to the terminal box through the insulator. The complete coil assembly is then placed in the tank and gently slipped inside the vacuum heating and drying ovens to completely dehydrate the equipment and ensure long operating life.

Construction