Controllable Local Network Transformer Dual Tap Changer Voltage Regulation
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Solution Overview
Problem
Existing controllable local network transformers face challenges due to the complexity and cost of medium-voltage vacuum switches on the high-voltage side and the coarser adjustment steps on the low-voltage side, which limit precise voltage regulation and increase structural complexity.
Innovation Solution
A controllable local network transformer design featuring on-load tap changers on both high-voltage and low-voltage sides, utilizing vacuum switches and a controller for precise voltage adjustments, allowing for fine steps on the high-voltage side and coarse steps on the low-voltage side, with a bridging circuit for current management during switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If on-load tap changer is placed on high-voltage side with medium-voltage vacuum switches, then voltage regulation precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent divides the single on-load tap changer into two separate units: one on the high-voltage side with limited switching stages (coarse adjustment) and one on the low-voltage side with multiple switching stages (fine adjustment). This segmentation allows each unit to be optimized independently, reducing the complexity of individual vacuum switch assemblies while maintaining overall voltage regulation precision through coordinated operation of both units.
2Device complexity
If on-load tap changer is placed on low-voltage side, then device complexity is reduced, but voltage regulation precision deteriorates
Solution Approach 1:
The patent segments the voltage regulation function into two levels: coarse adjustment on the high-voltage side and fine adjustment on the low-voltage side. The low-voltage on-load tap changer provides multiple switching stages (e.g., 20 stages) that enable precise voltage regulation, while the high-voltage unit provides broader range adjustment. This segmentation allows the low-voltage side to achieve high precision without requiring an excessive number of vacuum switches.
Solution Approach 2:
The patent applies local quality by assigning different functional characteristics to different parts of the system. The high-voltage on-load tap changer is designed for coarse adjustment with fewer stages, while the low-voltage on-load tap changer is designed for fine adjustment with more stages. Each part is optimized for its specific function, allowing the low-voltage side to provide precise regulation where it is most needed while keeping overall device complexity manageable.
3Measurement precision
If on-load tap changer is placed on high-voltage side, then voltage regulation precision is improved, but cost increases
Solution Approach 1:
The patent segments the expensive high-voltage vacuum switch assembly into a simplified unit with fewer switching stages, reducing manufacturing cost. The majority of the voltage regulation precision is achieved through the low-voltage on-load tap changer, which uses cheaper low-voltage vacuum switches. This segmentation strategy maintains overall precision while significantly reducing the cost burden on the high-voltage side.
Solution Approach 2:
The patent replaces expensive medium-voltage vacuum switches with a combination of simpler high-voltage switches and multiple low-voltage vacuum switches. The low-voltage vacuum switches, being cheaper components, are used in greater numbers to achieve the required precision, effectively substituting expensive components with more affordable alternatives that collectively provide equal or better performance.
4Device complexity
If on-load tap changer is placed on low-voltage side, then device complexity is reduced, but adjustment step size increases
Solution Approach 1:
The patent segments the adjustment function into two levels: coarse adjustment on the high-voltage side and fine adjustment on the low-voltage side. The low-voltage on-load tap changer provides numerous switching stages (e.g., 20 stages) that create small adjustment steps, while the high-voltage unit provides broader range adjustment with larger steps. This segmentation allows the system to achieve fine adjustment steps without requiring an excessively complex single-unit design.
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 design achieves precise voltage regulation with reduced structural complexity and cost by allowing fine voltage adjustments on the high-voltage side while minimizing the complexity on the low-voltage side, providing a wide adjustment range with fewer switches and avoiding circulating currents.
Implementation Method 1
a controllable local network transformer for transforming the electrical voltage from the medium-voltage network to the lower voltage used in the low-voltage network
Implementation Method 2
Medium-voltage vacuum switches are disadvantageously complex and therefore expensive
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a controllable local network transformer, comprising at least one high-voltage coil on a high-voltage side, at least one low-voltage coil on a low-voltage side, a first on-load tap changer for the low-voltage side, wherein the first on-load tap changer is designed for switching between at least two different numbers of turns of the low-voltage coil and comprises at least one second switch for this purpose, and a second on-load tap changer for the high-voltage side, wherein the second on-load tap changer is designed for switching between at least two different numbers of turns of the high-voltage coil and comprises at least one second switch for this purpose.