With the acceleration of the global energy transition in 2026, China's transformer production is expected to exceed 2.2 billion kVA. Ultra-high voltage (UHV) projects, new energy bases, and urban grid upgrades are imposing higher requirements on power equipment. Moisture within insulation materials after transformer manufacturing, maintenance, or exposure to humidity can severely reduce dielectric strength, triggering partial discharges or even breakdown accidents.
According to industry standards, the moisture content in the core and coil assembly of transformers rated above 3kV must be controlled to less than 0.5% after drying. Traditional methods such as natural air drying or simple hot air baking can no longer meet the stringent demands of modern large-scale transformers (especially those rated 110kV and above). Therefore, employing specialized transformer drying equipment for deep dehydration has become a critical link in ensuring the intrinsic safety of power equipment.
II. Comparison of Mainstream Transformer Drying Processes in 2026
Currently, advanced transformer drying equipment on the market primarily adopts the following technical routes, each with distinct advantages:
1. Vapor Phase Drying (VPD)
Application Scenario: Large ultra-high voltage transformers (110kV and above).
Technical Principle: Utilizes kerosene vapor to release latent heat upon condensation in a vacuum environment, directly heating the core and coil assembly.
Core Advantages:
Uniform Heating: Strong vapor penetration ensures no dead angles, avoiding local overheating.
High Efficiency: Reduces drying time by 30%-50% compared to traditional hot air drying.
Insulation Protection: The low-temperature, oxygen-deficient environment effectively prevents aging of insulation paper.
2026 Trend: New-generation equipment integrates intelligent condensation recovery systems, reducing solvent loss rates to below 0.1%, making the process more environmentally friendly and economical.
2. Vacuum Hot Oil Spray Drying
Application Scenario: Medium-sized transformers and on-site maintenance.
Technical Principle: Heated insulating oil is atomized through nozzles and sprayed onto the surface of the core and coil assembly, combined with vacuum dehumidification.
Core Advantages:
On-line Processing: Certain models support drying with oil present, eliminating the need to lift the core and significantly reducing power outage time.
Precise Temperature Control: Oil temperature is typically maintained below 80°C to ensure the performance of the insulating oil does not degrade.
Dual Purification: Removes impurities and moisture from the oil simultaneously during the drying process.
3. Induction Heating Vacuum Drying
Application Scenario: Small to medium-sized dry-type transformers or specific winding structures.
Technical Principle: Utilizes electromagnetic induction to generate eddy currents within the windings, generating heat from the inside out to drive out moisture.
Core Advantages: Fast heating speed and high energy utilization efficiency, making it particularly suitable for compact dry-type transformer structures.
III. How Should Enterprises Choose the Most Suitable Transformer Drying Equipment?
Faced with diverse market demands, power equipment manufacturers and operation/maintenance units should focus on the following key indicators when selecting equipment:
Ultimate Vacuum Degree: Excellent equipment should achieve an ultimate vacuum of below 10Pa, which is the prerequisite for deep dehydration.
Temperature Control Precision: Must possess a control accuracy of ±1°C to prevent damage to insulation materials caused by overheating.
Level of Intelligence: Mainstream equipment in 2026 should come standard with PLC automatic control systems capable of real-time monitoring of dew point, vacuum degree, and temperature curves, automatically generating drying reports to comply with Industry 4.0 standards.
Energy Efficiency Ratio: Select models equipped with thermal energy recovery devices, which can reduce energy consumption by over 30%, responding to the green call of the national "Work Plan for Stabilizing Growth in the Power Equipment Industry (2025–2026)".
Safety Design: Must include multiple safety protection mechanisms such as explosion-proofing, leak alarms, and automatic fire suppression systems.
In 2026, a pivotal year for the high-quality development of power equipment, choosing efficient, intelligent, and reliable transformer drying equipment is not only a necessity for improving product quality but also a commitment to the responsibility of grid safety.
Has been deeply engaged in the power equipment field for many years, providing comprehensive transformer drying solutions for all voltage levels from 35kV to 1000kV. Our equipment integrates the latest vapor phase drying and vacuum spray technologies and has successfully served multiple national key projects.