20 kV dry-type power transformers design

The reduction of the voltage conversion steps (for example, three-step 110/35/10 (6) kV for two-step 110/20 kV) is one of the ways to improve the supply and distribution networks in Ukraine.
Such transition can be economically justified in case of the capital re-equipment of existing electric networks and the building of new ones. The main reasons for modernization are:

  • high wearout of existing networks (the age of some equipment exceeds 50 years);
  • to reduce the power losses during switching to a higher voltage for networks of the same length;
  • to increase of network capacity, which enlarges the volume of electricity supply for the same territory (some of the networks are at the limit of electric load);
  • to improve the quality of electricity supply (by reducing the accident rate, increasing the level of automation, which leads to a decrease of System Average Interruption Duration Index (SAIDI) and System Average Interruption Frequency Index (SAIFI) which for today in Ukraine exceed the normalized indicators.);
  • to decreasing of technological expenses involved in electric power supply;
  • to create reserve power supply capability for new electrical consumers connection in future.
Moreover, existing facilities and lines can be used during electric lines re-equipment.
Private company "ELTIZ" carries out necessary preparation of manufacture line for 20 kV dry-type power transformers production.
Winding construction "Polymer" (cast windings heavy silicone insulation cast ΚΛ) provides an opportunity to manufacture 20 kV dry power transformers. There is no need to change dry-type power transformer construction, materials or current manufacturing process. In addition, the price of HV power transformers is the same.
Insignificant mass-dimensional difference of 20kV and 6(10)kV dry-type power transformers equal power gives possibility to replace in case electric lines re-equipment.