Superconducting Cable for Railway Pantograph Current Limiting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Railway pantograph systems face issues with direct current propagation into alternating current circuits, leading to potential fires and damage to transformers, with existing solutions being costly, complex, or requiring rapid detection and disconnection, which can cause electric arcs.
Innovation Solution
Incorporating a superconducting cable in the intermediate circuit between direct and alternating current pantographs, which transitions from low to high resistance when a direct current intensity exceeds a critical threshold, preventing damage and allowing for automatic and cost-effective prevention of fire without additional control devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional circuit breakers are used to prevent direct current propagation into alternating current circuits, then fire prevention is improved, but device complexity and cost increase
Solution Approach 1:
The superconducting cable changes its electrical resistance parameter based on current intensity. Below the critical current threshold, it maintains zero resistance for efficient power transmission. When current exceeds the threshold, it transitions to a high resistance state, automatically blocking excessive direct current from propagating into the alternating current circuit, thereby preventing fires without requiring complex circuit breakers
Solution Approach 2:
The superconducting cable performs the protective function itself by autonomously changing its resistance state in response to current intensity. The cable detects and responds to excessive current conditions without requiring external control devices, sensors, or complex switching mechanisms, thus simplifying the overall system while maintaining fire prevention capability
2Reliability
If rapid disconnection of pantograph is implemented to prevent transformer damage, then transformer protection is improved, but electric arcs are generated causing additional damage
Solution Approach 1:
The superconducting cable is positioned upstream in the circuit to preemptively block excessive direct current before it can reach the transformer. By transitioning to high resistance state when current exceeds the critical threshold, it prevents the harmful current from propagating further, thereby protecting the transformer without requiring rapid disconnection that would generate damaging electric arcs
3Measurement precision
If additional control devices are added to detect and prevent direct current in alternating circuits, then detection precision is improved, but device complexity and cost increase
Solution Approach 1:
The superconducting cable inherently detects current intensity through its own physical properties and automatically responds by changing its resistance state. This eliminates the need for separate sensors, detectors, or control devices, maintaining precise current monitoring while simplifying the system architecture and reducing costs
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 superconducting cable effectively limits direct current flow to alternating circuits, reducing the risk of fire and transformer damage, and allows for safe and economical operation by automatically switching to a high resistance state when excessive current is detected, eliminating the need for rapid disconnection and reducing the risk of electric arcs.
Implementation Method 1
a superconducting cable disposed in the intermediate circuit (40) between said direct current pantograph (12) and the alternating current circuit (18) and configured to present a first state called superconducting state, in which the superconducting cable has a low resistance
Implementation Method 2
to switch in a second state called the critical state, in which the superconducting cable has a high resistance in the event of circulation, towards the circuit (18) alternating, of a direct electric current of intensity greater than the critical intensity
Data Source
Figure 1~2
Figure 3~5
Figure 6
AI summary
The invention relates to a railway pantograph system for capturing an electric current from a catenary (32) in which an alternating or direct electric current flows, intended to supply a motor unit (16) of a railway vehicle comprising a first direct current supply circuit for the motor unit, called the direct circuit (20), a second alternating current supply circuit for the motor unit, an intermediate circuit (40), connecting the two supply circuits, and a direct current pantograph (12), adapted to connect the intermediate circuit (40) and the catenary (32), and to transmit to said intermediate circuit (40) an electric current from the catenary (32).The system is characterized in that the intermediate circuit (40) comprises at least one superconducting cable (36) configured to exhibit high resistance in the event of the flow of a direct electric current of intensity greater than a predetermined intensity towards the alternating circuit (18).