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The Largest Substation In Croatia

Installation of two completely new substations (TS-384 and TS-390) and the replacement of the power center in substation TS-303.

Electrical Installations & Engineering


INA d.d. - Rafinerija Nafte Rijeka

The Rijeka Oil Refinery is part of INA d.d., and it performs its activities within the company. The goal of the Refinery is profitability and sustainability, strengthening synergies and operational flexibility through increasing logistical connectivity, as well as further improving the competitiveness of the Rijeka Oil Refinery through increasing energy efficiency, operational availability, and improving the degree of conversion through investment in a plant for processing heavy residues.

The activity of the Refinery is the management of refinery production in Rijeka, the activities of the location in Sisak, business development, the commercial wholesale network on the domestic market, and trading activities on foreign markets. It also manages the logistics network for the storage and distribution of petroleum products, as well as the purchase and sale of natural gas and the production of oils and lubricants that meet the highest European standards.


Largest Substation in Croatia

The project took place at the Rijeka oil refinery in the Republic of Croatia. Its main objectives were to enhance the electrical infrastructure by constructing and installing two new substations (TS-384 and TS-390) and replacing the existing power center cabinet with a new Schneider Electric OKKEN power center in substation TS-303. The project involved extensive engineering, assembly, and installation work to ensure the successful implementation of the upgraded electrical system.

The TS-384 Substation

One of the key components of the project was the construction of the TS-384 substation, which aimed to supply power to the new DCU plant (Delayed Coker Unit), a facility designed for processing heavy residues. The scope of work included:


  • The construction of a cable space area covering approximately 3000m2
  • Installation of 1800m of cable trays with a width of 600mm
  • Installation of 350m of cable channels with a width of 200mm
  • Laying and connecting approximately 30km of low-voltage cables for interconnections between cabinets within the substation (ranging from 2.5mm2 to 500mm2)
  • Laying and connecting 3km of medium-voltage cables from the transformer to the 6kV facility
  • Laying and connecting 2km of high-voltage cables from the transformer to the 35kV facility
  • Assembly of 130 sets of GH Roxtec frames for cable sealing and management.

Ground Floor - Switchgear Room

  • Assembly, connection, and functional testing of distribution-control cabinets, including power centers, MCCs, NN (low-voltage) compensation cabinets, VFD (variable frequency drive) cabinets, and various other low-voltage cabinets.
  • Assembly and connection of medium-voltage (6kV AIS) and high-voltage (35kV GHA) cabinets, including busbar connections and internal wiring.
  • Installation and connection of low-voltage busbar distribution systems, totaling 6 sets with a length of 55m, and medium-voltage busbar distribution systems, totaling 2 sets with a length of 30m.
  • Installation and connection of batteries for AC and 110VDC UPS power supply.
  • Assembly and connection of oil transformers, including radiators, tanks, oil filling, and diagnostic testing.
  • Assembly and connection of a diesel generator with a capacity of 375kW.

First Floor - Fire and Gas Room

  • Installation of cable trays in a double-floor system, including cable trays with widths of 600mm, 400mm, and 200mm.
  • Assembly of 22 distribution-control cabinets.

The TS-303 substation reconstruction

TS-303 substation was dedicated to supplying power to motors used for handling oil, diesel, and other processed products between storage tanks and processing facilities. The tasks included:

  • Demolition of the existing power center.
  • Disconnection and extension of existing cables.
  • Installation of new foundations for the new power center.
  • Assembly of a new power center with 10 front-facing and 10 back-facing panels, totaling 77 drawers.
  • Interconnection of busbars and cables between cabinet panels.
  • 3D scanning of the incoming field for the creation of busbar connections with existing transformer busbars.
  • Reconnection of all disconnected and extended cables.
  • Functional testing and commissioning of the upgraded system.

Conclusion: The electrical infrastructure upgrade at the Rijeka oil refinery involved the construction and installation of two new substations and the replacement of an existing power center cabinet. The project encompassed various activities, including the construction of cable spaces, assembly and connection of distribution-control cabinets.


Electrical Installations & Electrical Cabinet Assembly

To address the objectives of enhancing the electrical infrastructure and ensuring the successful implementation of the upgraded electrical system at the Rijeka oil refinery, our solution involved the following key steps:

Construction of TS-384 Substation: We constructed the TS-384 substation to supply power to the new DCU plant, designed for processing heavy residues. This involved the construction of a cable space area, installation of cable trays and channels, laying and connecting low-voltage, medium-voltage, and high-voltage cables, as well as assembly of GH Roxtec frames for cable sealing and management.

Switchgear Room: We assembled, connected, and functionally tested distribution-control cabinets, including power centers, MCCs, NN compensation cabinets, VFD cabinets, and other low-voltage cabinets. We also installed and connected medium- and high-voltage cabinets and busbar distribution systems. Furthermore, we assembled and connected oil transformers, a diesel generator, and installed AC and 110VDC UPS power supply batteries.

Fire and Gas Room: We installed cable trays in a double-floor system, including various widths, and assembled distribution-control cabinets.

TS-303 Substation Reconstruction: We demolished the existing power center and installed new foundations for the new power center. Assembly of the new power center included front-facing and back-facing panels, interconnection of busbars and cables, and 3D scanning for busbar connections. We also reconnected all disconnected and extended cables, performed functional testing, and commissioned the upgraded system.

By implementing these solutions, we successfully enhanced the electrical infrastructure at the Rijeka Oil Refinery. The construction and installation of two new substations and the replacement of the existing power center improved the refinery's operational flexibility, energy efficiency, and overall competitiveness.

The upgraded system ensures a reliable power supply for the processing of heavy residues and enables the efficient handling of oil and other processed products.

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