Rehabilitation of the main transformer substations and construction of new mobile substations with adjacent distribution devices and connecting equipment, designed to increase the power supply from 6 kV to 20 kV – in Troyanovo-Sever and Troyanovo-3 mines

Siemens EOOD - Bulgaria


Assigned: 2012 / Completed: 2014

Project description

The project envisages reconstruction of 4 stationary Substations with the purpose to increase their power supply from 6 kV to 20 kV, and thereby reduce the losses of electricity on the power transmission grid. Furthermore, project includes delivery of 35 pcs. 20 kV mobile distribution devices mounted on a platform, construction of 8 pcs. 20/6 kV mobile substations and retrofit of 1 pc. 20/6 kV existing mobile substation, equipment of 9 pcs. excavators to change the power supply voltage from 6 kV to 20 kV.


  • Dismantle of existing equipment;
  • Supply, and installation of power, control and communication cables;
  • Electrical works – Primary Commutation: Installation of 110/20/6 kV power transformers and 20/6 kV power transformers; installation of new 20 kV Switchgears
  • Construction of new 20/6 kV mobile Substations, installation of the required MV equipment; installation of rectifiers and condenser-type batteries; manufacturing and installation of control and power panels;
  • Electrical works – Secondary Commutation: Installation and wiring of control panels, control cabinets, substitution of differential protection for 110/20/6 kV power transformers;
  • Control tests and commissioning of the installed equipment;
  • Manufacture of covered compartments - container type, for construction of 20/6 kV mobile Substations;
  • Manufacture of sledge-type platform with mounted covered compartment onto it, for installation of 20 kV mobile distribution switchgear (outdoor installation);
  • Engineering and programming of SCADA system;
  • Construction of grounding installation;
  • Construction of lighting installation;
  • Construction of HVAC installation.



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