Reconstruction of 6 kV Switchgear in 110/6.3 kV Substation Poliesterni vlakna

Electricity System Operator EAD (ESO EAD)

Yambol, Region of Yambol

Date of assignment: April, 2023/ Completion date: November, 2023

The assignment includes replacement of all existing 6 kV switchgear at the 110/6.3 kV substation ‘Poliesterni vlakna’.

The existing outdated 6 kV switchgear was replaced with SIEMENS NXAir switchgear. EL KONTROL did installation, wiring and commissioning.

Scope of executed activities includes installation of oil transformers in 110 kV switchgear, construction of foundations for LV transformers in 110 kV switchgear, secondary activities, power metering, connection of the newly installed equipment to the earthing installation, construction of lighting installation in 6 kV switchgear and construction of power and socket installation in the switchgear compartment.

Finishing works of painting walls and ceilings, levelling floor screed, construction works of facade doors, construction of cable routes for 6 kV cable lines, were also carried out.


EL KONTROL is Siemens VAR Partner for completion of air-insulated medium-voltage switchgear NXAIR.

NXAIR is a medium-voltage switchgear up to 17.5 kV, up to 40 kA provides the user with a platform upon which to build a reliable electrical network.

If applied for power supply companies or different industry and offshore applications - NXAIR stands for maximum operational and personal safety, highest reliability, and operator friendliness. Thanks to its compact dimensions, minimum use of components requiring maintenance, and its simple and reliable operating mechanisms, NXAIR is real value for money, as life cycle cost calculations show.