HVDC Insulation Barrier Pair with Counter-Flow Dielectric Channels
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Solution Overview
Problem
Existing insulation systems for high voltage inductive devices, particularly in HVDC applications, fail to provide sufficient dielectric properties at both ends of the winding, leading to inadequate electric withstand strength and increased complexity in manufacturing.
Innovation Solution
An insulation system with an innermost barrier pair covering the majority of the winding structure in the axial direction, featuring a first flow path for dielectric fluid flow in one axial direction and a second flow path in the opposite direction, with dielectric fluid changing direction at least once upon entry and exit, and fewer openings to enhance creepage path performance and dielectric strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If multiple openings are provided in the insulation system for oil flow, then cooling efficiency is improved, but dielectric strength and creepage path performance deteriorate
Solution Approach 1:
The insulation system is divided into multiple barriers (innermost barrier pair and outer barrier pair) with each barrier having selective openings. This segmentation allows different barriers to serve different functions: inner barriers provide cooling pathways while outer barriers maintain dielectric strength, resolving the contradiction between cooling efficiency and dielectric performance
Solution Approach 2:
Different barriers are designed with different opening configurations tailored to their specific locations and functions. The innermost barriers have openings optimized for cooling flow, while outer barriers have fewer or differently positioned openings to maintain creepage path performance. This local differentiation allows simultaneous optimization of cooling and dielectric properties in different regions
2Temperature
If complex flow path configurations are used to improve cooling, then cooling efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The complex cooling function is achieved through segmentation into multiple simple barriers with basic openings, rather than requiring a single complex molded structure. Each barrier is a relatively simple component that can be manufactured independently, reducing manufacturing complexity while achieving sophisticated cooling through the combined effect of multiple barriers
Solution Approach 2:
The insulation system uses a nested arrangement where innermost barriers are placed inside outer barriers, with each layer contributing to the overall cooling function. This nested structure allows complex multi-directional cooling flows to be achieved through simple sequential barriers, avoiding the need for complex integrated structures
3Productivity
If barriers with many openings are used for fluid communication, then cooling performance is improved, but creepage path length and dielectric performance decrease
Solution Approach 1:
The fluid communication function is segmented across multiple barriers rather than requiring large openings in single barriers. This allows cooling flows to be achieved through multiple small openings distributed across different barriers, maintaining creepage path length while enabling effective cooling through cumulative flow capacity
Solution Approach 2:
The outer barriers act as intermediary structures between the innermost barriers and the external environment. They provide additional flow pathways that mediate between the need for cooling (requiring open pathways) and the need for dielectric strength (requiring long creepage paths), allowing both requirements to be satisfied through the intermediate flow paths
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 increases the electric withstand strength and simplifies production by extending the creepage path, improving dielectric strength, and reducing the number of openings, thereby enhancing the insulation system's robustness and manufacturing simplicity.
Implementation Method 1
transformer oil, which can absorb the heat generated in the winding
Implementation Method 2
When oil is absorbing heat in the winding, it has to escape from the winding and be replaced by cool oil which can absorb additional heat
Implementation Method 3
proper insulation of equipment such as inductive devices is necessary so as to ensure the safe operation thereof
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
This disclosure relates to an insulation system (1-1) for a winding structure (11). The insulation system (1-1) comprises an innermost barrier pair (3) arranged to cover a majority of the winding structure (11) in the axial direction (A) of the winding structure (11) inside and outside the barrier structure (11) relative the curvature of winding turns of windings of the winding structure, wherein at least one barrier of the innermost barrier pair (3) defines a first flow path (3-1) allowing flow of a dielectric fluid (F) mainly in a first axial direction between the winding structure (11) and the at least one barrier when the insulation system (1-1) is in a assembled state; and a first outer barrier (5) arranged radially inwards or radially outwards relative each barrier of the innermost barrier pair, wherein the first outer barrier (5) defines a second flow path (5-1), parallel to the first flow path (3-1), allowing flow of a dielectric fluid (F) mainly in a second axial direction opposite the first axial direction, wherein the insulation system (1-1) is arranged such that a dielectric medium (F) is able to flow from the second flow path and enter the first flow path (3-1) at one axial end portion of one of the barriers of the innermost barrier pair (3) and at the other axial end portion of one of the barriers of the innermost barrier pair (3) exit the corresponding first flow path (3-1), wherein each barrier of the innermost barrier pair (3) has a contiguous envelope surface extending between the one axial end portion and the other axial end portion of each barrier of the innermost barrier pair (3). It is also presented an inductive device in which the insulation system (1-1) is arranged.