Transformer bushings are essential components that safely transfer current from inside the transformer to external circuits. Traditional
oil-immersed capacitive bushings (oil-paper bushings) suffer from sealing problems, moisture ingress, insulation aging, and overheating, contributing to a high failure rate.
In particular, 500 kV and above oil-paper bushings have shown frequent failures and have even caused transformer fires, posing major risks to power grid safety. To address these issues,
dry-type transformer bushings have become a safer alternative due to their fireproof, explosion-proof, maintenance-free, and high-mechanical-strength properties.
Dry-type bushings use solid insulation materials, replacing oil-filled insulation. Common materials include:

Due to excellent mechanical and insulation characteristics, epoxy-fiber dry bushings are suitable for a wide range of transformer environments.

Dry-type bushings can be designed for multiple installation scenarios:
Many models support multi-angle installation and customized structural designs.
Dry-type bushings contain no oil, eliminating risks of leakage, fire, or explosion. Many historical transformer fires originated from oil-paper bushing failures—an issue avoided entirely with dry-type designs.
No oil level checks, pressure monitoring, or oil sampling are required. Dry bushings are lighter, impact-resistant, and require minimal long-term maintenance.
Solid insulation cores and composite housings provide high structural integrity, suitable for harsh vibration environments and seismic regions.
Dry-type bushings typically offer greater insulation thickness and higher safety margins—often exceeding 30% compared to oil-paper designs.
Hydrophobic silicone rubber sheds maintain superior performance in contaminated areas such as coastal or industrial zones.
Some field cases reported moisture issues, sealing defects, and partial discharge anomalies.
Only isolated batch-related issues have been noted; overall field reliability is excellent.
Importantly, no dry-type bushing failures have led to transformer fires, confirming the inherent safety of solid insulation systems.
Dry bushings are increasingly used in:

Due to safety, environmental protection, and low maintenance, dry-type bushings are gradually replacing traditional oil-paper bushings worldwide.

Future development emphasizes improved design structure, defect prevention, consistency control, and long-term reliability to meet the strict requirements of modern power grids.
Dry-type transformer bushings represent a major advancement in power system reliability. With their fireproof, explosion-proof, maintenance-free, and high-insulation characteristics, they provide safer and more stable performance for high-voltage and ultra-high-voltage applications.
Their adoption supports safer and more efficient operation in modern grids, renewable energy systems, and urban distribution networks.