Transformer Dielectric Drying Using RF Heating for Moist Pressboard
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Solution Overview
Problem
Conventional heating methods for moisture extraction in transformers, such as using kerosene vapor and hot air, are time-intensive and energy-consuming, particularly challenging for drying thick blocks of pressboard material, and it's difficult to ensure uniform drying across the material.
Innovation Solution
A dielectric heating method using high-frequency alternating electric fields at radio frequencies to generate heat directly within the moist regions of the transformer's dielectric material, utilizing internal and external electrodes to target specific areas for moisture extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional heating methods using kerosene vapor and hot air are used for moisture extraction, then the drying process can be performed, but the process becomes time-intensive and energy-consuming
Solution Approach 1:
The patent replaces conventional thermal conduction heating (mechanical/thermal system) with dielectric heating using high-frequency electric fields. The electric fields directly interact with water molecules in the dielectric material, converting electromagnetic energy directly into heat within the material bulk, thereby dramatically reducing drying time and energy consumption while eliminating the need for kerosene vapor and hot air circulation systems
Solution Approach 2:
The patent changes the heating parameter from low-frequency thermal conduction to high-frequency electric field interaction. By operating at radio frequencies, the electric field frequency matches the relaxation frequency of water molecules, maximizing dielectric heating efficiency and enabling rapid moisture extraction without excessive energy input
2Manufacturing precision
If conventional heating methods are used for thick blocks of pressboard material, then heating can be applied, but uniform drying across the material becomes difficult to ensure
Solution Approach 1:
The patent replaces external thermal conduction heating with internal dielectric heating. The high-frequency electric fields penetrate the entire thickness of pressboard material simultaneously, generating heat uniformly throughout the bulk material. This eliminates the temperature gradient problem inherent in conventional heating where the outer surfaces heat faster than the core, ensuring uniform drying across thick sections without extending drying time
3Productivity
If high-frequency alternating electric fields are used to generate heat directly within moist regions, then faster and more energy-efficient moisture extraction is achieved, but the system complexity increases
Solution Approach 1:
The patent employs the transformer's own dielectric material and existing structure as the heating medium. The high-frequency electric fields utilize the dielectric properties of the insulation material and water molecules inherently present in the transformer, converting electromagnetic energy directly into heat within the material itself. This self-heating mechanism eliminates the need for complex external heating apparatus, making the system relatively simple despite the high-frequency power requirement
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method achieves faster and more energy-efficient moisture extraction with a reverse temperature gradient, preventing overheating and ensuring thorough drying by generating more heat where moisture is present, thus reducing time and energy consumption.
Implementation Method 1
The idea of the new drying technique utilizes the heat produced from interactions between a high-frequency alternating electric field and water molecules, to conduct the drying process
Implementation Method 2
heat is directly generated within the bulk of the material in the moist region due to the interaction the alternating electric field for instance with dipolar water molecules
Data Source
Figure 1~2
Figure 3A~3B
Figure 4A~4B
AI summary
A dielectric heating method for moisture extraction from an active part (10) of a transformer (1) is provided. The method comprises a step of configuring a system including at least one an apparatus (2) configured to generate electric fields alternating at radio frequencies, wherein the electric fields penetrate at least part of regions between freely selectable electrodes (3). The method further comprises a step of operating the at least one apparatus (2) for drying at least one moist region (7) of the active part (10) of the transformer (1), wherein the at least one moist region (7) is located at least partially between the freely selectable electrodes (3), so that the at least one moist region (7) is exposed to the generated alternating electric fields, resulting in heat generation within the at least one moist region (7).