400/220/110 kV Substation Maritsa-iztok – reconstruction of 110 kV Switchyard

Electricity System Operator EAD


Assigned: 2016 / Completed: June, 2019

Project description

Electrical Substation Maritsa-iztok is located in Galabovo Municipality, Stara Zagora District. Substation operates with three distribution Switchyards: 400 kV, 220 kV and 110 kV.
Rehabilitation of 110 kV Switchyard is set out in the Investment Program of Electricity System Operator EAD related to 2012-2022 Network development plan.

That is the second major project EL KONTROL executes on the territory of the Substation, after in 2010 we implemented the electrical part of the new 400 kV Switchyard.


Rehabilitation of 110 kV Switchyard is an engineering project, including elaboration of detailed design; delivery, installation and commissioning of electrical equipment.

A detailed design was elaborated, and when approved by ESO EAD in April, 2017, EL KONTROL started with rehabilitation of the existing 110 kV.

Execution of assigned activities started with dismantle of existing 110 kV equipment and adjacent structures. New concrete foundations were constructed and steel galvanized structures were erected. EL KONTROL delivered and installed the following equipment: disconnectors, current and voltage measuring transformers produced by ABB, support insulators produced by CERISOL, circuit breakers produced by SIEMENS. New Equipment was primary connected, power and control cables were laid and connected.

Project also included manufacturing and installation of control-relay cabinets, power supply panels, electro-metering panels, telecommunication panels.

Concrete roads and road accesses were reconstructed.

Constructed were cable ditches, drainage system of the Switchyard, new inner and outer fences. 

Lighting installation, earthing installation and lightning protection installation were constructed.

Reconfiguration of existing MicroSCADA control system was also implemented within the Project.

At the last stage of the rehabilitation all installed equipment was tested and commissioned, and the 110 kV Switchyard was put under operational use.



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