From diagnosis to commissioning
A sensitive project in a demanding industrial environment
In the chemical industry, certain pieces of equipment play a critical role in maintaining production continuity. When a transformer reaches the end of its service life, its replacement becomes a strategic operation that goes far beyond a simple equipment swap. This was precisely the context of this project, carried out at the Novacarb chemical plant, a subsidiary of the Humens group, which manufactures and markets sodium bicarbonate and sodium carbonate.
A major constraint accompanied this project: the new transformer had to strictly match the electrical characteristics of the existing transformer in order to guarantee parallel operation with the other transformers on site. The transformation ratio, vector group, impedance, and electrical behavior therefore had to be perfectly controlled to ensure operational continuity and stability.
Main technical characteristics :
- Hermetically sealed ONAN step-down transformer
- Flat wall tank + radiators
- Rated power: 12.5 MVA
- Voltage: 19.4 kV / 5.37 kV
- Temperature rise: 60/65 K
- Short-circuit impedance (Ucc): 9.7%
- Vector group: Dyn11
- Frequency: 50 Hz
- DETC with 5 positions
- Compliant with IEC 60076 and Ecodesign standards
Behind these technical specifications was a true turnkey project, managed from start to finish by celduc® transfo.
1 – Understanding the existing installation before taking action
As is often the case with this type of project, everything started long before the arrival of the new transformer. The initial phases focused on precisely analyzing the existing installation and understanding the site constraints.
The transformer room had limited dimensions and required particularly precise integration of the future equipment. Handling access, existing connections, and available space were studied in detail in order to anticipate every stage of the project.
This preparatory phase is fundamental. It helps secure future operations and avoid unforeseen issues once work begins. Every survey, measurement, and inspection directly contributes to the project’s final success.
2 – Designing a solution adapted to the site
The new transformer could not be installed without a comprehensive reflection on its environment. The objective was not simply to replace equipment, but to improve the existing installation while respecting site constraints.
The teams worked on the mechanical integration of the transformer to optimize its installation within the existing room. Maintenance access, radiator layout, and safety clearances were all carefully considered.
The project also included the installation of a new self-extinguishing oil containment system. This upgrade enhanced site safety while meeting current environmental requirements. In a sensitive industrial environment, this type of equipment plays a key role in risk management.
At the same time, the entire transformer supervision system was modernized. Safety information from the DGPT2 protection device had to be transmitted to the upstream and downstream switchgear cells in order to ensure continuous transformer monitoring and immediate response in the event of an anomaly.
3- Manufacturing and testing of the new transformer
In parallel with the site preparation activities, the new transformer was manufactured and subjected to a full series of factory acceptance tests. These tests verified its electrical performance, proper operation, and compliance with the project specifications.
To ensure the continuity and reliability of the site’s operations, it was decided not to disconnect the existing transformer until all tests on the new unit had been successfully completed and validated. This approach was adopted to avoid any risk of prolonged downtime in the event of an issue with the new equipment. Once the test results had been approved and the transformer had been declared fully compliant, the replacement operations could proceed with complete confidence.
4 – Removal of the existing transformer
Once the studies had been validated, the project entered its operational phase with the removal of the existing transformer.
This stage required rigorous organization. Operations were prepared jointly with the site teams in order to fully secure the intervention area. Electrical isolation procedures, lifting operations, and handling access routes were defined in advance to ensure smooth execution of the work.
A detailed handling plan was established, and a lifting supervisor was present to coordinate all operations. In this type of intervention, precision and communication between teams are essential, especially when working in confined spaces and handling equipment weighing several tons.
The old transformer was then successfully extracted from the room under fully controlled conditions.
5 – Preparing the transformer room for the new installation
After removal of the old equipment, the transformer room was fully prepared to receive the new transformer.
This intermediate phase is often less visible but remains essential. The supports were inspected, anchoring systems adapted, and the new containment system installed. The teams also prepared the future electrical connections in order to minimize intervention time during final installation.
Everything had to be ready before the arrival of the transformer to guarantee fast and safe installation.
6- Preparation of the installation area and transformer recycling
Following the removal of the existing transformer, the installation area was prepared to accommodate the new equipment. The original oil retention pit was filled and levelled in order to create a flat and stable foundation for the installation of the new retention bund. This modification was necessary to meet the requirements of the new transformer configuration and to facilitate future maintenance operations.
At the same time, the decommissioned transformer underwent a controlled dismantling process. The insulating oil was drained and handled in accordance with environmental regulations before being sent to approved treatment channels. The transformer itself was then dismantled, with its various materials—including copper, steel, and other recyclable components—sorted and recovered through specialized recycling processes.
These operations ensured both the environmental compliance of the project and the readiness of the site for the installation of the new transformer.
7 – Delivery and installation of the new transformer
The delivery day is always a major milestone on a project of this scale.
The transformer was transported to the site by special convoy before being carefully handled into its final position. Despite access constraints and the limited dimensions of the transformer room, operations were completed according to schedule thanks to the preparation work carried out upstream.
Once positioned, the transformer was aligned and mechanically secured before electrical connections began.
8 – Electrical connections
Following mechanical installation, the teams carried out the transformer connections on both the primary and secondary sides.
At the same time, the protection systems and DGPT2 signal transmissions were tested to ensure proper communication with the upstream and downstream switchgear cells.
Every inspection carried out at this stage is essential before final energization.
9 – Commissioning: the decisive moment
After several weeks of studies, preparation, and on-site work, the project reached its most anticipated stage: commissioning of the new transformer.
Before energization, a complete series of tests was performed to verify proper operation of the installation. Protections, alarms, electrical measurements, and supervision systems were all thoroughly checked.
Then comes that unique moment when the transformer takes load for the first time.
Values remain stable, protection systems communicate correctly, and the installation gradually returns to normal operation. Behind this successful commissioning lie weeks of coordination, anticipation, and collective effort.
A turnkey project delivered with precision and expertise to ensure the site's electrical reliability and operational safety.
Much more than a transformer replacement
This project perfectly illustrates what transformer replacement in a demanding industrial environment involves today, as well as the expertise that celduc transfo brings to its customers. Beyond supplying the equipment, the entire project must be mastered: engineering studies, safety, handling, supervision, electrical connections, testing, and documentation.
Each stage directly contributes to the final reliability of the installation and the site’s energy continuity.
Because in industry, replacing a transformer is not simply about installing new equipment. Above all, it is about sustainably ensuring the safety, performance, and operational continuity of a strategic production facility.