Dry Transformer Coil with Integrated Grounded Shield
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Dry-type transformers lack inherent protection against accidental contact with live components, posing a hazard to operating and maintenance personnel, and their size is increased due to the need for grounded housings to ensure safety.
Innovation Solution
A grounded, electrically conductive shield is integrated into the radially outer surface of the transformer coil, using insulating strips or metallization, to create a barrier structure that can be safely touched, which also serves as a cooling channel, reducing the overall size and enhancing mechanical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a grounded housing is used to protect against accidental contact, then safety protection is improved, but the overall size of the transformer increases due to required dielectric distances
Solution Approach 1:
The protective barrier is segmented into multiple insulating strips arranged radially around the coil, creating a distributed protection system that eliminates the need for a single large grounded housing while maintaining required dielectric distances
Solution Approach 2:
The protection system transitions from a three-dimensional grounded housing enclosing the transformer to a two-dimensional radial barrier structure on the coil surface, reducing the overall volume requirement while maintaining safety
2Device complexity
If air is used as an insulating medium to simplify construction, then construction complexity is reduced, but insulation distances must be increased due to limited insulation capacity
Solution Approach 1:
The insulating barrier uses composite material construction with fiber rovings impregnated with resin, creating a material with superior insulation properties that allows reduced insulation distances while maintaining safety with air as the cooling medium
3Reliability
If the barrier structure is made with insulating strips and protective wall to protect against contact, then safety protection is improved, but device complexity increases
Solution Approach 1:
The barrier structure serves multiple functions simultaneously: electrical insulation, mechanical protection, and structural support for the coil, eliminating the need for separate protective components and reducing overall device complexity
Solution Approach 2:
The insulating barrier is merged with the coil structure itself, integrating the protective function directly into the winding assembly rather than adding it as a separate external component
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 effective protection against accidental contact and allows for a safer, more compact transformer design by ensuring all manually accessible areas can be touched without risk, while maintaining electrical integrity and reducing insulation distances.
Implementation Method 1
the voltage stress occurring during operation is withstood. This makes it possible to provide the radially outermost barrier wall with a grounded, electrically conductive shield that can be safely touched by a person who is also at ground potential
Implementation Method 2
Such resin-impregnated fiber rovings, which are also known under the name 'prepreg' in a dry intermediate state of the resin, are heated to a polymerization temperature after the actual winding process and form a mechanically very strong structure during the cooling process
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a dry-type transformer coil (10, 32, 34, 36, 52, 54, 56) comprising a hollow cylindrical coil with at least one radially inner (12) and one radially outer (14) winding. A barrier structure extending at least partially around the coil and extending at least along its axial length is provided on the radially outer surface of the coil. This barrier structure comprises at least one layer of ribs (16) made of an insulating material and at least one barrier wall (18) radially supported by these ribs. The outermost barrier wall (18) has an electrical shield (20, 42, 58, 60, 62).The invention also relates to a dry transformer comprising a transformer core with at least two core legs, wherein a dry transformer coil (10, 32, 34, 36, 52, 54, 56) according to the invention is arranged around each of the at least two core legs (26), the respective electrical shield (20, 42, 58, 60, 62) of which is connected to earth potential (24, 44, 64).