In 1963, the Kerala government decided to form a company that designs, manufactures and supplies power transformers in India.

The company has supplied and installed first power transformer (rating 4 megavolt-ampere, 66/11 kilowatt) to Kerala State Electricity Board in 1966.

[7] In June 2007, the government, NTPC Limited and TELK signed the Business Collaboration and Shareholders’ Agreement.

The winding and insulation of 400 kV current transformers are carried out in a humidity controlled, dust free atmosphere.

A transformer bushing is an insulated device that allows an electrical conductor to pass safely through a grounded conducting barrier.

TELK was the first Indian company to manufacture 420 kV oil impregnated paper condenser bushings in the year 1970.