China’s First 110 kV Transformer with Fully Domestic Aramid Paper: What It Means for Insulation Buyers

TL;DR

• In August 2026, China energized its first 110 kV transformer built on a fully domestic insulation system — Chinese-made aramid paper paired with Chinese-made synthetic ester oil — at the Jiangshan substation in Guangxi.
• The unit passed a full multi-year test program covering electrical compatibility, field distribution, thermal behavior, and short-circuit withstand.
• For transformer makers outside China, the milestone signals that high-performance insulation no longer has to be imported from a handful of European specialists — the qualified supplier menu has permanently expanded.
• European incumbents remain excellent. But in a market with 160-week lead times, a second qualified source with 20–30% lower cost is risk management, not a compromise.

For decades, a quiet dependence defined the transformer industry: the highest grades of aramid paper, pressboard, and insulating oil came from a small circle of European and North American specialists. Transformer makers everywhere — in Europe, India, the Middle East, Brazil — built their designs around those suppliers. When delivery slipped, projects slipped. When prices rose, margins absorbed it.

In August 2026, a small but symbolic crack appeared in that order. China commissioned its first 110 kV transformer using a fully domestic insulation scheme: domestically produced aramid paper paired with domestically produced synthetic ester oil. The unit, built by Jiangsu Huapeng Group together with the Electric Power Research Institute of China Southern Power Grid, went into service at the 110 kV Jiangshan substation in Fangchenggang, Guangxi. It is one transformer — but it closes an assumption that has shaped the industry for half a century: that high-end transformer insulation must be imported.

What the Jiangshan Transformer Actually Proved

The transformer in question, model SRZ20-40000/110-NX2, combines aramid insulation paper — the high-temperature, high-strength material family most associated with Nomex-type products — with synthetic ester oil, a biodegradable dielectric fluid. Both were previously among the most import-dependent items in Chinese transformer manufacturing. The development program, run with China Southern Power Grid’s research institute and Chongqing University’s laboratory platform, put the domestic paper-oil combination through a full-dimensional test matrix: electrical compatibility, electric and magnetic field distribution, fluid thermal behavior, and short-circuit mechanical withstand. It passed.

The reported results go beyond simple import substitution:

• Higher overload tolerance. The insulation system’s elevated thermal class reduces operating temperature rise and significantly improves short-term overload capacity — increasingly valuable as load growth outpaces grid reinforcement.
• Smaller footprint. Aramid’s dielectric strength lets engineers shrink clearances and reduce tank volume and weight, cutting substation land use, civil works, and overall project cost.
• Longer life, lower noise. The new insulation system resists corrosion and aging better than conventional oil-cellulose systems and runs quieter in service.
• Cleaner end-of-life. Synthetic ester oil is biodegradable, aligning with the environmental requirements now baked into grid procurement in Europe and elsewhere.

The significance is not the machine itself. It is what the machine proves: the full insulation chain — from base fiber to finished paper and oil — can now be sourced domestically in China without compromising performance at transmission voltage.

Why This Matters for Transformer Makers Outside China

If you build transformers and currently source high-grade insulation from the traditional European names — Pucaro, Weidmann, Krempel, Enpay — the Jiangshan transformer is worth reading twice.

First, it signals a capability shift. China’s insulation industry has spent the past decade closing the quality gap across the entire portfolio: transformerboard and pressboard, flexible composite laminates, rigid glass-epoxy sheets, and now high-performance aramid paper systems. The aramid-ester project is the flagship proof point, but the underlying capability extends well beyond it. IEC-grade pressboard, DMD/NMN/NHN flexible laminates, FR4/G10 rigid laminates, and CNC-machined insulation components are all produced domestically to the standards international buyers historically imported for.

Second, it changes the procurement math. The traditional trade-off was simple: European quality, European price, European lead times. The Chinese alternative now offers comparable performance with a different set of numbers — and in a market where generator step-up transformer lead times have stretched past 160 weeks, component supply chains matter more than ever. We covered the equipment-side picture in our analysis of the global transformer shortage; the materials side is following the same logic.

Consider a real case. A Spanish transformer manufacturer switched its pressboard sourcing from a European incumbent to a Chinese supplier. Procurement costs fell 20–30%. Lead times dropped from 10–12 weeks to 5–7 weeks, with emergency replenishment available in two weeks. Inventory turnover improved from 90 days to 45 days. One supplier now covers the full insulation range — transformerboard, flexible laminates, rigid sheets, and machined components — where three used to be juggled.

The switch happened because the quality barrier fell. When quality matches and the price is 20–30% lower, the decision becomes arithmetic, not loyalty.

The Bigger Picture: Insulation Independence as an Industry Trend

The Jiangshan project is not happening in isolation. China’s grid investment envelope — roughly 5 trillion yuan across the two major grid companies during the 15th Five-Year Plan period (2026–2030), with State Grid alone committing about 4 trillion yuan — is funding exactly this kind of domestic substitution at scale. At the same time, the mandatory energy-efficiency standard GB 20052-2024, effective February 2025, is pushing transformer designs toward higher efficiency grades and higher thermal classes, which raises the performance bar for insulation materials and rewards suppliers who can deliver at volume.

For buyers, the practical implication is simple: the menu of qualified insulation suppliers has permanently expanded. The European incumbents remain excellent — this is not an argument against them. Pucaro, Weidmann, Krempel, and Enpay built the technical foundations this industry stands on, and their materials remain benchmarks. But in a supply-constrained market, holding a second qualified source with comparable quality, shorter delivery, and lower cost is not a luxury. It is risk management.

The aramid milestone proved the technical case. The market is already proving the commercial one.

What Buyers Should Do Now

You do not need to redesign your transformers to act on this shift. A pragmatic qualification path looks like this:

• Start with the highest-volume materials. Pressboard and transformerboard consume the most tonnage in a typical oil-immersed design — qualify a second source there first. Our PSP 3050 pressboard is a common starting point for exactly this exercise.
• Extend into flexible laminates. DMD, NMN, and NHN composite insulation covers layer and slot insulation across thermal classes 130–220, with NHN aramid laminates directly relevant to high-temperature designs.
• Consolidate rigid and machined parts. FR4/G10 epoxy glass sheet, tube, and rod plus CNC-machined laminated wood components can be sourced from the same supplier, collapsing three vendor relationships into one.
• Test before you commit. Request samples, run your standard aging and compatibility protocols, and pilot on a non-critical product line — the same discipline you would apply to any new material source.

The Spanish case above followed exactly this sequence: samples first, a pilot order, then a phased switch. The result was not a leap of faith — it was a qualified, auditable supply decision.

Frequently Asked Questions

Q: What is aramid paper used for in transformers?
Aramid paper is a high-temperature insulation material (thermal class up to 220) used for conductor wrapping, layer insulation, and barriers in compact, high-overload, and ester-filled transformer designs. For a broader overview of insulation paper types and applications, see our complete guide to insulation paper.

Q: Is Chinese-made aramid paper comparable to Nomex-type products?
The Jiangshan transformer is the strongest public evidence to date: a fully domestic aramid paper and ester oil system passed complete electrical, thermal, and short-circuit testing at 110 kV and entered grid service in August 2026. As with any material change, buyers should still run their own qualification testing.

Q: Does switching insulation suppliers mean redesigning the transformer?
Usually not. Pressboard, flexible laminates, and rigid sheets are typically qualified as like-for-like material substitutions within an existing design. High-temperature aramid systems can enable a more compact redesign, but that is an option, not a requirement.

Q: What lead time and cost difference should I realistically expect?
In the documented Spanish case, pressboard procurement costs fell 20–30% and standard lead times dropped from 10–12 weeks to 5–7 weeks. Actual figures depend on grade, volume, and logistics — but the direction is consistent across buyers who have qualified Chinese sources.

Summary: A Second Qualified Source Is Now on the Table

China’s first fully domestic aramid-paper 110 kV transformer does not end the European insulation industry — it ends the assumption that there is no alternative. For transformer makers facing long lead times and rising material costs, the qualified supplier base has grown, and qualifying a Chinese source is now standard risk management rather than an experiment.

At SIDA, we supply the full transformer insulation range — pressboard and transformerboard, DMD/NMN/NHN flexible laminates, FR4/G10 rigid laminates, and CNC-machined components — with free samples for qualification testing. If you are evaluating a second source, talk to our engineering team:

📞 +86-15958243831 | 📧 jessie.feng@sidanm.com | 💬 WhatsApp: +86-15958243831 | 🌐 sidanm.com/contact-us

References

1. Liyang Municipal People’s Government — 国内首台全国产芳纶绝缘纸-合成酯油110kV变压器顺利投运 (August 2026)
2. Sina Finance — 国内首台全国产芳纶绝缘纸-合成酯油110kV变压器顺利投运 (August 2026)
3. China Daily — China to invest 5 trillion yuan in power grid over next 5 years (February 2026)
4. GB 20052-2024 — Minimum allowable values of energy efficiency and the energy efficiency grades for power transformers (full text)
5. US Data Center Projects (Reuters/Wood Mackenzie data) — US power companies buying equipment five years out as AI data center boom worsens transformer shortages (July 2026)
6. SIDA — The Global Transformer Shortage: How Chinese Manufacturing Is Closing the Gap (September 2026)