Erection of 110/20 kV Substation Helios

ABB Bulgaria EOOD; Client: National Electric Company EAD

Kosharitsa Village, Nesebar Municipality

Assigned: 2011 / Completed: 2011

Project description

110/20 kV Substation Helios is designed to power supply the consumers in Sunny Beach resort. It increases the transmission capacity of the 110 kV electricity system ring of the Southern Black Sea, and improves the security of the electricity grid in Burgas Region.

The Substation is built entirely by EL CONTROL, from undevelopped terrain.


  • CONSTRUCTION WORKS – Erection of cable ditches, concrete foundations portal constructions, installation of portal constructions, construction of temporary roads, roads in 110 kV Switchyard, road link to the Substation; complete construction of Control Building; construction of water supply and drainage system; landscaping; construction of earthing loop.
  • PRIMARY COMMUTATION - installation of ComPass commutation and measuring units, Nabla busbar system, circuit-breakers, surge arresters, support insulators in 110 kV Switchyard and connection of equipment thereto; installation of 20/0.4 kV auxiliary power transformers and active resistance for earthing of 110/20 kV power transformer, delivery and installation of lighting system, installation of 20 kV switchgear. Assembly, delivery and installation of AC/DC auxiliary panels.
  • SECONDARY COMMUTATION – Delivery, laying and connection of power and control cables, cable racks, copper busbars; installation of battery and rectifier.
  • COMMISSIONING WORKS – Commissioning of the equipment in 110 kV Switchyard, control of earthing loop, operational tests.
  • TELECOMMUNICATIONS – Laying, splicing and testing of fiber optic lines.
  • SCADA – Installation and connection of SCADA panel.
  • CONTROL ELECTRICITY MEASUREMENT – Installation and connection of measuring panel.


A special feature about the Project for construction of 110/20 kV Substation Helios is the extremely short deadline for its completion. Due to the tourist season, the first stage of the Project was completed by EL KONTROL for a record time of 72 days, and the Substation was put under operation in June 2011.

Second stage of the Project was finished in October 2011.