On-Load Tap-Changer Linear Switching Segmentation
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Solution Overview
Problem
Current on-load tap-changers for power transformers face challenges in achieving a large regulating range while minimizing load losses, particularly in HVDC transformers, where plus-minus regulation results in high losses near the minus position, and linear regulation has limited range.
Innovation Solution
The on-load tap-changer incorporates two tap selector parts with change-over selectors that switch between them to extend the linear regulation range to 35 positions, reducing load losses and allowing for a more efficient voltage regulation by connecting the diverter switch to either selector part based on the regulation range, thereby decreasing the need for cooling equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If plus-minus regulation is used to achieve large regulating range, then the regulating range is extended, but load losses increase significantly near the minus position
Solution Approach 1:
The tap-changer is divided into two separate tap selector parts (first and second), each handling a portion of the regulation range. This segmentation allows the system to maintain linear connection topology throughout the full range while distributing the regulation burden across two parts, thereby achieving large regulating range without the high losses associated with plus-minus regulation.
2Loss of energy
If linear regulation is used to minimize load losses, then load losses are reduced, but the regulating range is limited
Solution Approach 1:
Two tap selector parts are combined in series to extend the linear regulation range. The first tap selector part handles the first portion of the regulation range, and the second tap selector part handles the second portion. By merging these two parts with a change-over selector, the system achieves both low load losses (maintaining linear connection) and large regulating range (35 positions total).
3Adaptability or versatility
If two separate tap selector parts are used to extend linear regulation range, then regulating range increases to 35 positions, but device complexity increases
Solution Approach 1:
The change-over selector serves multiple functions: it switches between the first and second tap selector parts, manages the diverter switch connections, and enables seamless transition between the two selector parts. This multi-functionality reduces the need for additional dedicated components, thereby managing device complexity while achieving extended regulation range.
4Volume of moving object
If the regulating winding is connected closer to the main winding for compact design, then the physical distance is reduced, but electrical isolation requirements become more challenging
Solution Approach 1:
The tap-changer structure serves as an intermediary element between the main winding and regulating winding. By positioning the tap selector and stationary contacts in the spatial gap between the two windings, the design achieves compact physical dimensions while maintaining adequate electrical isolation through the inherent insulation design of the tap-changer components.
Data Source
Figure 1~3
Figure 2a~2b
Figure 4a~4b
AI summary
The present invention relates to an on-load tap-changer (33) adapted for linear switching comprising: - a tap selector (34) including a first selector part (36) having a plurality of first stationary contacts (38) for connection to a regulating winding (40) and two movable contacts (VA, HA) adapted to connect to the stationary contacts, and a second selector part (42) having a plurality of second stationary contacts (44) for connection to the regulating winding and two movable contacts (VB, HB) adapted to connect to the second stationary contacts, - a diverter switch (16) connected to the tap selector for providing tap changing, and - two change-over selectors (46, 48) connected between the diverter switch (16) and the tap selector (34), and arranged to select between connecting the diverter switch to the first selector part and connecting the diverter switch to the second selector part.