On-Load Tap Changer Retrofit with Vacuum Valves
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Solution Overview
Problem
The challenge lies in transitioning from an in-oil arc switching scheme to a vacuum-valve scheme for on-load tap changers without requiring replacement or modification of the existing oil tank, which is difficult due to differences in component layout and the complexity of actuation mechanisms in limited spaces.
Innovation Solution
The design allows for a change-over switch that is compatible with the existing oil tank, employing a vacuum-valve scheme with a parallel link mechanism that simplifies the actuation of current-carrying conductors and ensures compatibility with the in-oil arc switching scheme, enabling attachment and detachment without disturbing the oil tank's structure, thus allowing continuous use without replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a vacuum-valve scheme change-over switch is introduced, then the maintenance interval is extended and reliability is improved, but the device complexity and space requirements increase
Solution Approach 1:
The patent combines the actuation mechanisms of multiple vacuum valves into a single integrated structure. The common actuating mechanism uses a shared driving source and linkage system to simultaneously control the opening and closing of multiple vacuum valves, reducing the overall complexity despite the increased reliability benefits of using vacuum valves instead of oil-based switching
Solution Approach 2:
The change-over switch is designed with a universal actuation system that can control multiple vacuum valves through a common driving mechanism. This multi-functional design allows a single actuating system to perform the function of what would traditionally require multiple separate mechanisms, addressing the complexity issue while maintaining the reliability advantages of vacuum valve technology
2Reliability
If a vacuum-valve scheme change-over switch is introduced, then the maintenance interval is extended, but the space required in the oil tank increases
Solution Approach 1:
The patent employs a nested arrangement where vacuum valves and their actuating mechanisms are positioned within the existing oil tank structure. The common actuating mechanism is integrated into the limited space by nesting components within each other, allowing the vacuum-valve scheme to be implemented without proportionally increasing the overall volume occupied in the oil tank
Solution Approach 2:
The patent optimizes the spatial arrangement by utilizing vertical and radial dimensions within the oil tank. The vacuum valves and actuating mechanisms are arranged in a compact three-dimensional configuration that efficiently uses the available space, preventing the volume requirement from increasing linearly with the added complexity of the vacuum-valve system
3Stability of the object's composition
If the change-over switch is detached and reattached, then the oil tank structure remains intact, but the connection reliability may be affected
Solution Approach 1:
The patent divides the change-over switch into separable modules that can be detached and reattached without damaging the oil tank. The connection interface is designed as a distinct segment with standardized coupling mechanisms, allowing for safe disassembly and reassembly while maintaining structural integrity and connection reliability through precise mating features
Solution Approach 2:
The patent introduces a specialized connection structure that acts as an intermediary between the change-over switch and the oil tank. This intermediate coupling mechanism facilitates reliable attachment and detachment while protecting both the switch and tank from damage, ensuring that connection reliability is maintained despite the repeated assembly and disassembly operations
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 solution ensures the oil tank can be used for a long time without replacement or modification, simplifies the actuation mechanism, and achieves space savings by using a parallel link mechanism that enhances the retrofit function and reliability of the current-carrying contact mechanism.
Implementation Method 1
a breaker unit (49) which interrupts a current
Data Source
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AI summary
An on-load tap changer which ensures the compatibility of an oil tank when an interchange from the in-oil arc switching scheme to the vacuum-valve scheme is made, improves a retrofit function, achieves a space saving by simplifying components, and facilitates a construction of an actuation mechanism is provided. A change-over switch 46 for the vacuum-valve scheme is placed in an oil tank 50 filled with an insulation oil 56. The change-over switch 46 is provided with a main contact contained in vacuum valves 2, 3, 5, 6, and current-carrying conductors 7, 8 to reduce a current flowing in the main contact, and parallel link mechanisms actuating the current-carrying conductors 7, 8 in a parallel manner. A stationary contact 47 capable of contacting with and separating from the current-carrying conductors 7, 8 is attached to the internal wall surface of the oil tank 50. The change-over switch 46 is freely attachable to and detachable from the oil tank 50 with the stationary contact 47 being attached to the oil tank 50.