When upgrading a power grid or establishing a large-scale industrial facility, stepping up to a 35kV voltage class changes the engineering game completely. At this level, a transformer isn’t just a bigger version of a standard distribution unit; the physical stresses, dielectric challenges, and thermal dynamics require a much higher standard of manufacturing.
As a dedicated 35kv oil immersed transformer manufacturer, we often host international procurement teams at the Baitong Electric facility. They usually want to look beyond the specification sheets and see exactly how we build these heavy-duty units. Today, we are opening our workshop doors to share what goes into engineering a reliable 35kV transformer.
1. Mastering the Dielectric Challenge: Vacuum Drying
At 35,000 volts, even a microscopic drop of moisture inside the insulation can cause a catastrophic short circuit.
Before any 35kV unit is placed into its tank on our production floor, the assembled iron core and copper windings must go through a rigorous vacuum drying process. We place the active parts into large vacuum ovens to extract every trace of moisture from the solid insulation (kraft paper and pressboard). Only when the moisture content drops below absolute minimum standards do we proceed to the next step.
2. Precision Coil Winding
The heart of any 35kV transformer is its winding structure. Because these units often face severe electrical surges and short-circuit mechanical forces from the grid, standard winding techniques are not enough.
Our skilled technicians use continuous and interleaved winding methods for the high-voltage coils. This specific technique ensures an even distribution of impulse voltage across the coils (for instance, during a lightning strike). We also heavily reinforce the mechanical clamping of the core and coils so they won’t deform under extreme electromagnetic stress.
3. High-Grade Oil Filtration and Sealing
As an experienced 35kv oil immersed transformer manufacturer, we know that the mineral oil does exactly two things: it cools the core, and it stops electrical arcing.
However, raw transformer oil isn’t ready for 35kV immediately. Before filling the corrugated tanks, we pass the mineral oil through a high-vacuum filtration plant. This removes dissolved gases and water, drastically increasing its dielectric breakdown voltage. Once filled, our hermetically sealed tanks ensure that the oil never comes into contact with the outside atmosphere, preventing future oxidation and keeping maintenance costs low for our end-users.
4. Routine and Type Testing Before Dispatch
We don’t rely on guesswork. Every single 35kV transformer that leaves the Baitong Electric loading dock has to pass a battery of tests.
- Measurement of winding resistance and voltage ratio.
- Applied AC voltage tests to ensure the insulation holds up.
- Induced over-voltage withstand tests.
- DGA (Dissolved Gas Analysis) of the oil to verify internal health.
These tests ensure compliance with international grid codes, meaning when the equipment arrives at your site, it is ready to be energized safely.
Partner with a Direct Manufacturer
Sourcing high-voltage equipment shouldn’t involve guessing games with middlemen. When you work directly with Baitong Electric, you get full transparency—from the grade of silicon steel we cut to the final coat of anti-corrosion paint we apply.
Planning a high-voltage substation or industrial expansion? Our engineering team is ready to review your single-line diagrams and provide a customized technical proposal.
Contact the Baitong Electric team for your 35kV transformer requirements today
