Non-Liquid Immersed Transformer Cooling Pipe with Convolutions
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Solution Overview
Problem
Existing cooling systems for non-liquid immersed transformers face challenges such as insufficient heat dissipation, increased size and cost, flammability, and environmental hazards, particularly when using air, hydrocoolers, or dielectric fluids.
Innovation Solution
A cooling system utilizing a heat exchanger with a main feeding and return pipe, and a cooling pipe with convolutions that extends the path of a non-conductive cooling fluid like water, reducing electric current flow and incorporating conductive connectors to manage electrical fields, thereby enhancing cooling capacity and safety while minimizing footprint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If hollow conductor pipes are used for circulating cooling fluid, then cooling capacity is improved, but the size and footprint of the transformer is substantially increased
Solution Approach 1:
The cooling pipe is nested within the coil winding structure, with the pipe positioned inside the winding bore or between winding layers. This allows the cooling fluid to flow through the center of the coil where heat generation is highest, maximizing cooling efficiency while minimizing the external footprint of the transformer.
Solution Approach 2:
The cooling pipe is configured to extend along the axial direction of the coil winding rather than requiring radial expansion. By utilizing the axial dimension and creating a compact spiral or serpentine path within the existing winding volume, the system achieves enhanced cooling without increasing the transformer's overall footprint.
2Temperature
If hollow conductor pipes are used for circulating cooling fluid, then cooling capacity is improved, but manufacturing difficulty and cost are increased
Solution Approach 1:
The cooling function is extracted from the conductor itself and implemented through a separate, simple pipe structure. Instead of using complex hollow conductors, the invention uses a standard pipe positioned within the winding, separating the electrical conduction function (performed by solid conductors) from the cooling function (performed by the fluid-carrying pipe). This dramatically simplifies manufacturing while maintaining cooling effectiveness.
Solution Approach 2:
The cooling system is segmented into a simple pipe structure that can be independently manufactured and then integrated into the winding assembly. The pipe is divided into sections that can be bent or connected to form the required path, allowing for easier fabrication and assembly compared to monolithic hollow conductors.
3Temperature
If hollow conductor pipes are used for circulating cooling fluid, then cooling capacity is improved, but additional losses due to eddy currents are increased
Solution Approach 1:
The cooling function is extracted from the electrical conductor and assigned to a separate non-conductive or minimally conductive pipe. This separation eliminates the eddy current losses that would occur in hollow metallic conductors, as the pipe material is chosen to have low electrical conductivity while maintaining adequate thermal conductivity for effective heat transfer.
Solution Approach 2:
The electrical conductivity parameter of the cooling pipe material is changed to be low (reducing eddy currents) while the thermal conductivity is maintained at adequate levels (ensuring cooling effectiveness). Materials such as plastics, ceramics, or coated metals are used to achieve this parameter combination, fundamentally changing the material properties from traditional metallic hollow conductors.
4Temperature
If dielectric fluids are used for cooling, then cooling capacity is improved, but flammability and environmental hazards are increased
Solution Approach 1:
The system uses water or water-based fluids as the cooling medium, which are non-flammable and environmentally benign. This creates an inert, safe cooling environment that eliminates the fire hazards associated with traditional dielectric fluids like oil or synthetic esters, while still providing adequate cooling capacity through proper heat exchanger design.
Solution Approach 2:
Water, the proposed cooling fluid, is inexpensive, readily available, and environmentally safe even if leaked or discharged. Unlike expensive dielectric fluids that require special handling and disposal, water can be used freely without environmental concerns, making it an ideal sustainable cooling medium.
5Object-affected harmful factors
If non-dielectric fluids are used for cooling, then environmental safety is improved, but electrical discharge risks are increased
Solution Approach 1:
The cooling fluid is extracted from the high-voltage electrical environment and confined to a separate pipe system that is electrically isolated from the windings. By positioning the pipe within the winding bore or between layers and providing electrical insulation, the conductive cooling fluid is kept away from high-voltage regions, eliminating electrical discharge risks while allowing the use of environmentally safe water-based fluids.
Solution Approach 2:
An electrical insulation layer or barrier is introduced as an intermediary between the conductive cooling fluid and the high-voltage electrical components. This intermediary allows the use of water-based cooling fluids while preventing electrical discharge, as the insulation layer blocks the electrical field from interacting with the conductive fluid.
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 solution provides a cost-effective, environmentally friendly, and safe cooling system with increased cooling capacity, reducing the risk of fire and electrical issues, while maintaining a compact transformer size.
Implementation Method 1
A longer path increases the electric resistance of the cooling fluid which enables the cooling system to work with cooling fluids with low electrical conductivities
Implementation Method 2
a pump may be used in order to force the flow of the cooling fluid through the cooling pipe
Implementation Method 3
The cooling pipe also comprises a plurality of convolutions to extend the path of the cooling fluid
Data Source
AI summary
A non-liquid immersed transformer is provided. The transformer includes a magnetic core and a coil winding forming a plurality of winding turns around the magnetic core and a cooling system. The cooling system includes a heat exchanger, a main feeding pipe and a main return pipe, and a cooling pipe for the flow of a cooling fluid. The cooling pipe extends at least partly along the coil winding between a first point adjacent to an end of the coil winding, and a second point adjacent to the other end of the coil winding. The cooling pipe also includes a plurality of convolutions to extend the path of the cooling fluid between one end of the winding and one of the main feeding pipe and the main return pipe.