History and tradition

As a member of the Končar Group, Instrument transformers’ evolution followed development within the whole Group. Below are the company’s most significant years:

  • 1947 – manufacture of 36 kV oil-immersed instrument transformers
  • 1952 – manufacture of 123 kV ITs
  • 1962 – manufacture of 245 kV ITs
  • 1965 – manufacture of epoxy resin insulated instrument transformers
  • 1973 – manufacture of 420 kV ITs
  • 1991 – reorganization and registry under present name 
  • 1992 – manufacture of combined ITs (type VAU)
  • 2003 – manufacture of 525 kV and 765 kV ITs
  • 2006 – founding of joint-venture in Shenyang, China (with TBEA)
  • 2006 – manufacture of power voltage transformers 
  • 2010 – manufacture of 800 kV ITs

The development process of instrument transformers was not unintentional. A clear transition from lower to higher voltage levels was a result of Yugoslavian electricity network’s development, which took place every 10 years. During 1970s it matched 400 kV.

The 525 kV and 765 kV series were built per requirements from a Russian customer. The country’s extremely low winter temperatures and long distances to be covered are reason for transmitting electrical energy on very high voltage levels.

The 800 kV series were manufactured per requirements from an Indian customer, and were in many aspects the most demanding units built to date. The higher than standard lightning impulse voltages (2400 kV), demanding core specs and rated capacitance as well as using porcelain as external insulation, all had unfavorable impacts on mechanical design. The units were successfully shake-tested in a certified laboratory before delivery in order to prove their seismic withstand capabilities.

The 1992 combined unit innovation is also historical trademark worth mentioning. The unique and patented design recieved worldwide recognition, distinguishing us as the only manufacturer in the world that is capable of offering such a solution.

In 2006 we took our first steps with power voltage transformers. Today, our market presence, propagating our unique open core concept, proves quality of design, as well as relevance of those first steps.