Transformer Winding Assembly Shielding for Partial Discharge Reduction
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Solution Overview
Problem
High-temperature applications in oil-filled distribution transformers with medium operating voltage ≥72.5 kV experience increased risk of partial discharges and flashovers due to high electrical field strength at the high-side voltage end lead, where traditional shielding materials are not effective.
Innovation Solution
The winding assembly connects the winding conductor to a switching line with a larger cross-section inside the winding, forming a crimp connection and surrounding it with an electrical shielding to reduce electrical field strength, using a conductive layer and common insulation to prevent conductive connections and flashovers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional shielding materials are used at the high-side voltage end lead, then the structure is simple, but the electrical field strength remains high causing partial discharges and flashovers at high temperatures
Solution Approach 1:
The patent introduces an intermediary shielding structure consisting of a conductive layer and common insulation arranged between the high-side voltage end lead and surrounding components. This intermediary shielding structure mediates the electrical field distribution, reducing field strength without requiring fundamental redesign of the transformer components.
Solution Approach 2:
The patent employs composite shielding materials combining a conductive layer (such as copper or aluminum foil) with common insulation materials. This composite structure provides both electrical shielding and thermal insulation properties, effectively reducing electrical field strength while maintaining high-temperature reliability.
2Ease of operation
If the connection of switching line to winding conductor is arranged outside the winding, then accessibility for connection is improved, but electrical field strength increases and insulation is reduced
Solution Approach 1:
The patent nests the switching line connection within the winding structure, placing the connection point inside the winding rather than outside. This nesting arrangement allows the winding conductors themselves to provide insulation around the connection, reducing electrical field strength while the shielding structure provides additional protection.
3Reliability
If shielding is added to reduce electrical field strength, then reliability improves, but manufacturing complexity increases
Solution Approach 1:
The patent modifies the shielding structure parameters by using a conductive layer with specific material properties and arranging common insulation in specific configurations. These parameter changes optimize the shielding effectiveness while keeping the manufacturing process compatible with existing transformer assembly techniques.
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
This configuration significantly reduces the risk of partial discharges and arcing in the high-side voltage end lead range by shielding the electrical field, ensuring a secure and insulated connection within the winding.
Implementation Method 1
the connection is surrounded by an electrical shielding (6). Consequently, the electrical field of the winding is shielded from the switching line in a simple manner
Implementation Method 2
A crimp connection is created when two components are connected to one another by plastic deformation, such as by flanging, squeezing, crimping or folding
Data Source
AI summary
A winding assembly for a transformer, in particular with a medium operating voltage of Um≥79.5 kV, wherein the winding assembly includes at least one winding, which ends in a winding conductor, where the winding conductor is connected to a switching line, which is configured to interconnect the winding to other windings, and where the connection of the switching line to the winding conductor is arranged inside the winding so as to reduce the danger of partial discharges and flashovers in the high-voltage end-line region for high-temperature applications.