Substation Setup in Bursa: From Design to Provisional Acceptance

A new factory or a capacity increase often means building your own substation. A well-designed substation is the foundation of a safe, efficient and audit-ready facility — and the process involves considerably more engineering calculation and official procedure than it appears at first glance.

When Do You Need a Substation?

Once a facility's power demand exceeds what the utility can supply at low voltage, medium-voltage supply — and building your own substation — becomes mandatory. This threshold is crossed often, whether setting up a new factory on an OIZ plot or expanding capacity at an existing one. Substation need should be assessed at the feasibility stage alongside both current and planned load — a transformer that turns out undersized later directly caps production growth.

1. Right Power & Transformer Selection

Transformer rating is set against current and future load — a transformer sized only for today's need can become a bottleneck within a few years. Power-transformer selection follows IEC 60076-1:2011 — rated power, vector group (e.g. Dyn11), short-circuit impedance and cooling type (ONAN). Oil vs. dry-type depends on fire safety, location (indoor/outdoor) and maintenance conditions — in densely built OIZ plots, fire regulation often favors dry-type transformers.

2. MV Switchgear Selection

On the medium-voltage side, metal-clad or RMU cells are chosen by load profile and expansion plan. Incomer, metering, protection and transformer-feeder cells form the backbone of the system. Cell selection should account not just for today's feeder count but future expansion (an additional transformer, additional feeders) — adding cells later is far more expensive than leaving room from the start.

3. Short-Circuit & Protection Coordination

For provisional-acceptance files, a short-circuit calculation is mandatory in most OIZs. We calculate it per IEC 60909-0:2016 and set breaker/fuse selection through protection coordination on a selectivity basis. Without correct coordination, a fault at a lower level can needlessly trip an upstream protection device too — making it harder to locate the fault and causing an unnecessary wider outage.

4. Installation & Commissioning

We install the kiosk (prefabricated) or building-type substation and commission it safely with test protocols. This stage includes:

• Mechanical installation and cabling of the transformer and MV cells
• Insulation-resistance and continuity testing
• Protection-relay setting and function tests
• Earthing measurement and reporting — see our earthing measurement guide
• A final checklist before first energization

5. Provisional Acceptance

We prepare the provisional-acceptance file for the OIZ and utility completely and follow the process to the end. The file typically includes: project approval, short-circuit calculation, protection-coordination report, earthing measurement report and test protocols. An incomplete or incorrect file can delay energization by weeks — which is why getting the file right from the start matters as much as the fieldwork itself.

After Energization: YGİS

Once the substation is energized, every facility with its own substation is legally required to appoint a MV Operating Responsible engineer (YGİS) — most utilities already require this appointment before energization. We cover this in detail in our YGİS guide.

Common Mistakes

• Sizing the transformer only for today's load: without growth margin, a capacity increase forces an early, unplanned transformer investment.
• No expansion margin in cell count: adding cells later requires shutting down the existing system and extra cost.
• Skipping the short-circuit calculation early: doing it at the last minute during acceptance can force a retroactive change in protection-device selection.
• Preparing an incomplete acceptance file: the most common cause of energization delays.

FAQ

How long does substation setup take? It varies with project approval, equipment procurement and site conditions; depending on equipment lead time, it can take from a few weeks to a few months. Early planning is the key to managing procurement time without colliding with your production schedule.

Should I choose a kiosk or building-type substation? It depends on plot area, site layout, future expansion needs and budget. Kiosk-type is generally faster to install; building-type offers more flexibility for larger capacity and long-term expansion.

Is a short-circuit calculation mandatory for every facility? Most OIZs and utilities require a short-circuit calculation and protection-coordination report in the provisional-acceptance file — it's the proof that protection devices are correctly selected and will trip in the right sequence under a real fault.

Is there an additional responsibility needed after the substation is built? Yes — after energization, a YGİS appointment must be made for the facility's legal operation. SOREAS can handle the full process end to end, from installation through YGİS.