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Electrical power infrastructure

Substations and grid connection systems for high-capacity locations

We deliver complete substations — from the MV switching block (10/20 kV) and transformer to the main LV distribution assembly, protection and commissioning with the DSO.

MV block 10/20 kV Transformer Main LV assembly Commissioning
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The wider system picture

Substation: from the grid connection to every load

A compact or traditional substation is not an isolated component — it is the junction between the distribution network (10 kV or 20 kV) and the internal low-voltage installation of the facility. Every substation has three functional sections: the MV (medium-voltage) block, the transformer and the main LV distribution assembly.

Our experience in LV switchboard manufacturing and industrial installations allows us to treat the complete system — from connection conditions to end loads — as a single engineering project with one point of accountability.

GRID / TS ▮ ONLINE
SN 10/20 kV NN 400V IZLAZ 1 IZLAZ 2 IZLAZ 3

Energy flow from MV network to LV distribution

Service scope

MV block · Transformer · Main LV assembly

Every substation is dimensioned according to the required power, transformer type, enclosure type (kiosk, reinforced-concrete building, dedicated room) and grid connection conditions.

SN-01

Medium-voltage (MV) switching block — 10/20 kV

SF6 gas-insulated or vacuum switchgear for connection to the distribution network. Includes: MV busbar, voltage and current instrument transformers, protective relays, metering, signalling and interlock systems.

  • SF6 switching cells (incoming, metering cell, protection cell)
  • Current and voltage instrument transformers
  • Numerical protective relays (overcurrent, differential, earth fault)
  • Communication interface with DSO SCADA system
TR-02

MV/LV transformer

Oil-immersed or dry-type (cast-resin) transformation from 10 kV / 20 kV to 0.4 kV. Typical ratings 250–2000 kVA, sized to peak load and site growth reserve.

  • Oil-immersed units (400–2000 kVA) for indoor or outdoor use
  • Dry-type (cast-resin) transformers for buildings without oil containment
  • Temperature, oil level, gas monitoring and protection
  • Impedance matching for parallel transformer operation
NN-03

Main low-voltage (LV) distribution assembly

The main LV switchboard (MDB) behind the transformer distributes power to all outgoing circuits of the facility. The core of the low-voltage installation, built to IEC 61439.

  • Main incomer with metering and protection
  • Busbars to 4000 A, selective feeder protection
  • Reactive power compensation (capacitor banks) — cos φ ≥ 0.95
  • Metering and monitoring for energy management
CON-04

Connection infrastructure and coordination

Coordination with the DSO for technical connection conditions, documentation, approvals and inspection organisation.

  • Connection application — DSO technical connection conditions
  • MV cable route from connection point to substation
  • Coordination between designer, contractor and DSO inspector
COM-05

Testing and commissioning with the DSO

Complete testing to IEC/EN standards and handover with the distribution system operator (DSO) in accordance with grid connection procedures.

  • Insulation, loop impedance and earth electrode tests
  • Protective relay and communication verification
  • DSO handover, meter registration
SUP-06

Maintenance and technical support

Periodic inspections, SF6 pressure checks, cleaning, relay servicing and support for stable operation.

  • Annual and scheduled substation inspections
  • Protection relay setting verification
  • Emergency callout response
Delivery process

From connection conditions to system handover

Each phase has a technical objective, clear accountability and a documented result.

  1. 01

    Site and load analysis

    Required power, number of transformers, enclosure type (kiosk / masonry / dedicated room), growth reserve.

  2. 02

    Obtaining connection conditions

    DSO application, voltage alignment (10 kV / 20 kV), connection method.

  3. 03

    Engineering and coordination

    Single-line diagram, equipment selection, civil and electrical project coordination.

  4. 04

    Procurement and installation

    MV block, transformer, main LV assembly, cable routes and electrical works.

  5. 05

    Testing

    Measurements, protection verification, functional tests and handover records.

  6. 06

    Commissioning with DSO

    DSO inspection, meter registration, documentation handover to investor.

Reliable delivery

A substation that is safe and easy to maintain

A good MV/LV system must be selective in protection, clear to the service technician and ready for future increases in connection capacity.

  • 01 Protection selectivity from substation to final fuses
  • 02 Clear documentation (single-line diagram, test records, DSO papers)
  • 03 Equipment from certified manufacturers (ABB, Schneider, Siemens, Eaton)
  • 04 Expansion readiness: spare feeder ways, busbar capacity reserve, transformer margin
New substation or reconstruction

Planning a substation or an increase in connection capacity?

Send details about the location, planned load and connection voltage — we will provide a technical assessment and define the next step.

Discuss the grid connection → +385 98 936 4212