Electrical Fuse With Adjustable Inductance for Traction Networks
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Solution Overview
Problem
Existing electrical fuses in high-voltage traction networks face challenges in simplifying their construction and ensuring reliable operation, particularly in preventing overheating and welding of contacts due to current peaks, while also accounting for aging effects and varying environmental conditions.
Innovation Solution
An electrical fuse with an electro-pyrotechnic igniter and a movable separating element, utilizing an induction loop with adjustable inductance to provide ignition current based on current changes, and optionally incorporating an iron core for self-adjustment to temperature changes, allowing for variable setting of the limit value and galvanic isolation without additional components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fuse is designed with a high tripping threshold to avoid false tripping during normal operation, then the reliability of normal operation is improved, but the cable cross-sections must be chosen larger increasing device complexity and cost
Solution Approach 1:
The fuse incorporates an adjustable inductance mechanism that allows the tripping threshold to be dynamically adapted. The inductance can be adjusted based on the specific application requirements, enabling the fuse to distinguish between normal operating current peaks and actual fault conditions without requiring oversized cables. This dynamic adjustment resolves the contradiction by optimizing the tripping characteristics for each specific installation scenario.
Solution Approach 2:
The fuse design allows changing the inductance parameter to modify the tripping threshold characteristics. By adjusting the inductance value, the fuse can be tailored to different cable cross-sections and current profiles, enabling proper protection without requiring larger cables than necessary. This parameter adjustment capability resolves the contradiction between reliability and device complexity.
2Reliability
If the fuse size is increased to account for aging effects and maintain adequate tripping threshold, then the reliability under aging conditions is improved, but the initial tripping threshold becomes higher requiring larger cable cross-sections
Solution Approach 1:
The adjustable inductance mechanism allows the fuse to be optimized for its specific application rather than being designed for worst-case aging scenarios. The inductance can be set to provide appropriate margins for aging without excessively high initial thresholds, eliminating the need for oversized cables. This resolves the contradiction by finding the optimal balance between initial and aged performance.
Solution Approach 2:
The fuse incorporates temperature compensation mechanisms that automatically adjust its characteristics based on environmental conditions and aging effects. This self-adjusting capability ensures reliable operation throughout the fuse's lifespan without requiring excessive design margins, thereby avoiding the need for larger cable cross-sections while maintaining reliability under aging conditions.
3Speed
If a pyrotechnic igniter is used for rapid circuit separation in short circuit conditions, then the protection speed is improved, but the device complexity and safety requirements increase
Solution Approach 1:
The fuse design incorporates an intermediary adjustment mechanism (adjustable inductance) that mediates between the pyrotechnic igniter's rapid response and the need for controlled operation. The adjustable inductance allows optimization of the triggering characteristics to ensure rapid separation only when truly necessary, reducing unnecessary pyrotechnic activations while maintaining fast protection capability when needed.
4Adaptability or versatility
If the inductance is made adjustable to optimize tripping characteristics, then the adaptability to different operating conditions is improved, but the device complexity increases
Solution Approach 1:
The adjustable inductance mechanism provides dynamic adaptability to different operating conditions, cable cross-sections, and current profiles. This single adjustment parameter enables the fuse to be optimized for various applications without requiring multiple different fuse designs, thereby improving adaptability while keeping the overall device complexity manageable through a unified adjustable architecture.
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 solution ensures precise triggering at defined limit values, preventing overheating and contact welding, while adapting to aging and environmental changes, thus enhancing the reliability and efficiency of the electrical fuse in high-voltage traction networks.
Implementation Method 1
an induction loop (10a, 10b) which is designed to provide the ignition current via inductive coupling with at least one section (11a, 11b) of the busbar (5)
Implementation Method 2
an electro-pyrotechnic igniter (3)
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to an electrical fuse (1), a method for operating an electrical fuse, and an electrical traction network, comprising an electro-pyrotechnic detonator (3), a separating element (4) movable by means of the electro-pyrotechnic detonator (3), and a busbar (5) with a separating section (6), wherein the movable separating element (4) is arranged with respect to the electro-pyrotechnic detonator (3) and the separating section (6) of the busbar (5) such that the movable separating element (4) can begin to move after the electro-pyrotechnic detonator (3) has been triggered and can thereby cut the busbar (5) in the separating section (6), wherein the electrical fuse (1) has at least one triggering means (8a, 8b) which is configured to generate an ignition current necessary for triggering the electro-pyrotechnic detonator (3) based on a current passing over at least one section (11a, 8b).11 b) to provide the current carried on the busbar (5) or its change over time when the current carried on the at least one section (11a, 11b) of the busbar (5) or its change over time exceeds a limit value. The invention further relates to an associated method and an electric traction network.