Some projects come with a clear requirement and a specification that isn’t found in any catalog. That was the case with INGDELEC S.A.S.
The project required increasing the load capacity and changing the voltage level at a facility in El Espinal, Tolima, Colombia. The specifications were specific: 34,500 volts on the primary side, 13,200 on the secondary side, 1,500 kVA, dry-type encapsulated, with active thermal control. A transformer that wasn’t available in any standard model. So we designed it from scratch.
The challenge: a specification that isn’t listed in the catalog
When INGDELEC submitted the request, the first thing we did was to understand the full operational context. It wasn’t enough to know the power and voltages. We needed to understand what would happen to that equipment over its service life.
The installation in El Espinal, Tolima, involved a high ambient temperature environment and continuous operation. That, combined with the voltage difference between the primary and secondary sides and the type of load the equipment would have to handle, determined that the solution had to include active thermal control from the design phase onward—not as an optional accessory.
A 1,500 kVA transformer operating between 34,500 and 13,200 V, with an insulation level of 36/15 kV and a BIL of 145/95 kV. The correct solution was full encapsulation in epoxy resin: both primary and secondary windings. That option was not listed in the catalog.
The technical challenge was not simply to manufacture the transformer. It was to manufacture it properly: with the correct tolerances, with the connection group required by the system (Dyn5), with built-in thermal protection, and with the regulation capability required by the project.
The solution: a design tailored to the actual operation
The engineering team at Tesla Transformadores worked out the complete specifications before the product went into production. Each parameter was a technical decision based on a specific rationale.
Technical Specifications of the Manufactured Equipment
| Parameter | Specification |
| Type | Class F encapsulated dry-type transformer — custom design |
| Power | 1,500 kVA |
| Voltage Level | 36 / 15 kV |
| BIL (Basic Impulse Level) | 145 kV (primary) / 95 kV (secondary) |
| Primary voltage | 34,500 V |
| Secondary voltage | 13,200 V |
| Connection group | Dyn5 |
| Insulation | Primary and secondary windings encapsulated in epoxy resin |
| Temperature Class | Class F — 155 °C (support insulation) |
| Monitoring | Temperature kit with integrated PT-100 probes |
| Cooling | Forced ventilation |
| Regulation | ±2 × 2.5% |
| Standards | NTC · RETIE 2024 · IEC-EN |
| Manufacturing | Funza, Cundinamarca, Colombia |
| Installation | El Espinal, Tolima, Colombia |
| Customer | INGDELEC S.A.S. |
Why does every decision matter?
Epoxy resin encapsulation: the decision that defines this transformer
What sets this equipment apart is not an accessory: it is the way its coils are constructed. Both the primary and secondary windings are completely encapsulated in epoxy resin. This means there are no exposed parts, no air cavities where partial discharge can occur, and no progressive degradation due to moisture or environmental contamination.
The 36/15 kV voltage rating and the 145/95 kV basic impulse level (BIL) are not parameters that can be achieved with just any manufacturing process. They are achieved when the insulation system is properly designed starting with the winding—and resin encapsulation is what makes this possible in dry-type equipment.
Class F, Monitoring, and Ventilation: The Thermal Support System
The insulation of a Class F transformer and the thermal control accessories (PT-100 probes and forced ventilation) complement the design. In resin-encapsulated equipment, heat has no other means of dissipation than the resin itself and ventilation; therefore, Class F and the heat dissipation mechanisms are part of the system, not an extra. This level of control is especially important when the transformer operates as critical equipment in a project that cannot afford an unscheduled failure.
Dyn5 Group and ±2 × 2.5% Regulation: Compatibility as Specified
The Dyn5 connection group was defined based on the equipment’s compatibility with the electrical system in which it was to operate. The delta connection on the primary side isolates third-order harmonics; the star connection with a neutral on the secondary side allows for mixed loads and three-phase distribution systems with an available neutral.
The ±2 × 2.5% regulation range allows the transformation ratio to be adjusted without taking the equipment offline—a critical feature in installations where the line voltage may fluctuate.
From Funza to El Espinal: from design to installation
The transformer was manufactured at our plant in Funza, Cundinamarca, in accordance with our standard quality standards: routine tests, a signed testing protocol, and complete documentation for the RETIE certification process. From Funza to El Espinal, the equipment arrived on site ready for installation, complete with the technical documentation the project needed to move forward smoothly with electrical certification.
Not all projects fit into a catalog. And that’s not a problem—it’s an opportunity to excel at something few companies can do: design, manufacture, and deliver a custom transformer with the same rigor and on the same timeline as standard equipment. The key lies in understanding the project before designing the equipment. In asking the right questions from the start. In not delivering a generic transformer when the application calls for something specific.
That’s what we did with INGDELEC. And that’s what we can do for your project.
Does your project have non-standard requirements?
Tell us about the installation conditions. Our engineering team will review the specifications and propose a customized solution from the very beginning.
Does your project require a high-performance transformer?
Tell us about the installation conditions. Our engineering team will review the specifications and propose a customized solution from the very beginning.
✉ servicioalcliente@tesla.com.co
📞 +57 318 282 6314
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