Reconstruction of 110 kV Switchyard at 220/110/20/10.5 kV Substation Karnobat

DietsmannEnergoremont Holding AD, Sofia


Assigned: 2017 / Completed: 2018

Project description

Electrical Substation Karnobat is located in Karnobat Municipality, Burgas District. It has a 220 kV switchyard, a 110 kV switchyard, and a 20 kV indoor switchgear. Rehabilitation of the 110 kV Switchyard is set in the investment Program of the Electricity System Operator EAD.

Order for rehabilitation of the 110 kV switchyard includes partial delivery of equipment, execution of construction and electro-installation works.


Stage 1 – Delivery of equipment

  • Manufacture and supply of control relay panels, control cabinets, auxiliary panels, electro-metering cabinets, telecommunication cabinets
  • Delivery of portal constructions and building materials
  • Delivery of earthing busbar, wires, electrical materials

Stage 2 - Construction, electrical installation and commissioning

  • Dismantle of existing equipment, metal structures, steel-concrete structures, busbar systems, cables;
  • Construction of foundations, gate constructions, cable ducts, piping;
  • Installation of primary equipment: circuit breakers, disconnectors, current measuring transformers, voltage measuring transformers, supporting insulators;
  • Installation of busbar systems;
  • Laying and connection of power and control cables;
  • Construction of new foundations and mounting of 110/20kV power transformers onto them;
  • Construction of new 20kV cable connections between 110/20kV power transformers and 20kV indoor switchgear;Construction of earthing installation and lightning protection installation;
  • Construction of lighting installations - operative, guard, emergency and auxiliary lighting;
  • Construction of a new building – pump station;
  • Construction of fire extinguishing system for 220/110 kV autotransformer;
  • Building a fence;
  • Drainage and landscaping;
  • Construction of concrete roads and approaches.