Geneva Tap Changer Switching for Lower Flywheel Energy
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Solution Overview
Problem
Existing on-load tap changers face challenges in reliability and complexity when switching tap connections, leading to increased mass movement and flywheel energy requirements, which affect damping and efficiency.
Innovation Solution
A switching system utilizing a Geneva mechanism with a rotatable ring and driving wheel, where the rotatable ring is supported by a holder and driven by an eccentrically arranged drive shaft, reduces the complexity of the driving mechanism and minimizes mass movement, allowing for efficient and reliable switching between multiple tap positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional switching mechanism is used in the on-load tap changer, then the switching function can be achieved, but the complexity of the driving mechanism increases and reliability decreases
Solution Approach 1:
The switching mechanism is segmented into distinct functional components: the rotatable ring for position selection, the driving wheel for actuation, the connector for electrical connection, and the holder for structural support. This segmentation allows each component to perform its specific function efficiently, reducing overall system complexity while maintaining reliability
Solution Approach 2:
The rotatable ring acts as an intermediary element between the driving wheel and the connector. It receives rotational input from the driving wheel and translates it into precise angular positions for the connector, thereby simplifying the direct coupling between actuator and switch while enhancing reliability through controlled motion transmission
2Adaptability or versatility
If more individual tap positions are implemented, then the versatility of the on-load tap changer increases, but the mass that needs to be moved increases leading to higher flywheel energy requirements
Solution Approach 1:
The system employs dynamic motion control where the rotatable ring rotates to different angular positions corresponding to various tap positions. By making the positioning system dynamic and rotatable rather than using multiple fixed switching mechanisms, the patent achieves high versatility with minimal moving mass, thereby reducing flywheel energy requirements
Solution Approach 2:
Instead of adding more switching elements in the same spatial dimension, the patent utilizes rotational dimension - the rotatable ring can assume multiple angular positions (0°, 60°, 120°, etc.) to select different taps. This dimensional approach allows numerous tap positions without proportionally increasing the mass that must be moved
3Device complexity
If the rotatable ring is directly coupled with the holder, then the structure is simplified, but friction increases requiring more force to move the ring
Solution Approach 1:
The bearing arrangement serves as an intermediary between the rotatable ring and the holder. It introduces rolling contact elements that mediate the interaction between these two components, reducing friction from sliding contact to rolling contact while maintaining the simplified structural coupling
Solution Approach 2:
The bearing arrangement changes the friction parameter by introducing rolling elements. This transforms the friction characteristic from high static and kinetic friction (direct contact) to lower rolling friction, thereby reducing the force required to rotate the ring while keeping the structure simple
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 Geneva mechanism reduces the complexity and enhances reliability by allowing precise rotational movement with reduced friction and mass, enabling a large number of tap positions with lower flywheel energy and damping requirements, thus improving the overall efficiency and reliability of the on-load tap changer.
Implementation Method 1
The bearing arrangement comprises a plurality of bearings. The bearings are coupled to the holder. For example, the bearings comprise ball bearings that are arranged to support the rotatable ring with respect to the holder and to reduce a friction between the rotatable ring and the holder
Data Source
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AI summary
A switching system for an on-load tap changer comprises: - a Geneva mechanism (120, 150), wherein the Geneva mechanism (120, 150) comprises: - a holder (121, 151), the holder (121, 151) being fixed relative to a housing (101), - a rotatable ring (122, 152) with a recess (123, 153), the rotatable ring (122, 152) being supported by the holder (121, 151) and being rotatable relative to the holder (121, 151), - a connector (124, 154), the connector (124, 154) being rotatable together with the rotatable ring (122, 152) to electrically connect with a tap (102, 103, 104, 105) of the tap changer (100), - a rotatable driving wheel (125, 155) with a protrusion (126, 156), the protrusion (126, 156) being coupleable with the recess (123, 153) to rotate the rotatable ring (122, 152), the driving wheel (125, 155) being arranged inside the rotatable ring (122, 152).