Pressurized Air Molded Transformer Insulation and Cooling
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Solution Overview
Problem
Conventional molded transformers are limited to lower voltage and capacity due to the insulating and cooling performance of air at atmospheric pressure, restricting their application to around 33 kV in Japan and 77 kV elsewhere, and their cooling capacity is inferior to gas-insulated transformers like those using SF6.
Innovation Solution
A molded stationary induction apparatus with a closed vessel encapsulating air at higher pressure than atmospheric pressure, incorporating heat exchangers and a partition plate to enhance insulation and cooling, and optionally using fans to improve air circulation and cooling efficiency, while allowing for higher dielectric strength and capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If air at atmospheric pressure is used for insulation and cooling, then the transformer can be manufactured with simple structure, but the insulation performance limits voltage application to around 33 kV and cooling performance limits capacity to about 15 MVA
Solution Approach 1:
The patent applies parameter changes by pressurizing the air inside the sealed cabinet to higher than atmospheric pressure. This increases the density and dielectric strength of the air, thereby improving insulation performance between windings and between windings and ground, enabling higher voltage applications beyond the conventional 33 kV limit.
Solution Approach 2:
The patent applies parameter changes by pressurizing the air inside the sealed cabinet to higher than atmospheric pressure. This increases the density and heat capacity of the air, thereby improving cooling performance and enabling larger transformer capacities beyond the conventional 15 MVA limit.
2Device complexity
If air at atmospheric pressure is used for cooling, then the transformer structure remains simple, but cooling performance is insufficient for larger capacity applications
Solution Approach 1:
The patent applies parameter changes by pressurizing the air inside the sealed cabinet to higher than atmospheric pressure. This increases the density and heat capacity of the air, thereby improving cooling performance and enabling larger transformer capacities beyond the conventional 15 MVA limit.
Solution Approach 2:
The patent introduces a partition plate that divides the cabinet into a high-voltage winding chamber and a low-voltage winding chamber. This segmentation improves cooling efficiency by directing pressurized air flow through specific paths and enhances insulation by creating separate zones for different voltage levels.
3Ease of manufacture
If conventional molded transformer design is used, then manufacturing is straightforward, but voltage application is limited to around 33 kV in Japan and 77 kV abroad
Solution Approach 1:
The patent applies parameter changes by pressurizing the air inside the sealed cabinet to higher than atmospheric pressure. This increases the density and dielectric strength of the air, thereby improving insulation performance between windings and between windings and ground, enabling higher voltage applications beyond the conventional 33 kV limit.
Solution Approach 2:
The patent introduces a partition plate that divides the cabinet into a high-voltage winding chamber and a low-voltage winding chamber. This segmentation improves insulation by creating separate zones for different voltage levels, reducing dielectric stress, and enabling higher voltage applications while maintaining straightforward manufacturing processes.
4Adaptability or versatility
If air at atmospheric pressure is used, then the transformer can operate in simple environmental conditions, but cooling efficiency is lower compared to gas-insulated transformers
Solution Approach 1:
The patent applies parameter changes by pressurizing the air inside the sealed cabinet to higher than atmospheric pressure. This increases the density and heat capacity of the air, thereby improving cooling performance and reducing energy loss, achieving cooling efficiency comparable to or exceeding gas-insulated transformers while maintaining environmental adaptability.
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
Enables operation at higher voltages and larger capacities beyond conventional limits, with improved insulation and cooling performance, and facilitates easier maintenance and environmental compliance by using air instead of greenhouse gases.
Implementation Method 1
heat exchangers 4 for increasing the density of the air 7 inside the closed vessel 3 and cooling the air 7
Implementation Method 2
air 7 having a higher pressure than atmospheric pressure... improved insulation... higher dielectric strength
Implementation Method 3
heat exchangers 4 for increasing the density of the air 7 inside the closed vessel 3 and cooling the air 7
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A molded stationary induction apparatus is provided with: a winding the surface of which is covered with resin or an insulating material containing resin; a closed vessel in which the winding is housed and air having pressure exceeding atmospheric pressure is sealed; and a heat exchanger which cools the air in the closed vessel.