Bipolar Rail Leakage Detection via Earthed Third Conductor
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Solution Overview
Problem
Existing public transport systems with electric vehicles equipped with tires are unable to detect accidental contact between conductors or collector shoes and the vehicle body, leading to undetected leakage currents, while systems with earthed components suffer from false detections due to stray currents.
Innovation Solution
A public transport system with electrically insulated conductors and collector shoes, using a bipolar rail and floating power supply to detect leakage currents through the vehicle body, preventing false alarms and allowing for quick corrective measures, while also enabling efficient recharging and reduced infrastructure costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the electric vehicle is equipped with tyres and electrically insulated from the ground, then the vehicle can move freely and reduce friction, but the sensor cannot detect accidental contact between conductors and the vehicle body
Solution Approach 1:
The patent introduces a third electrical conductor (earthed conductor) as an intermediary reference point. This conductor serves as a mediator between the insulated vehicle body and the ground, enabling the sensor to detect leakage currents by measuring the potential difference between the insulated conductors and this earthed reference, thus resolving the detection problem while maintaining vehicle insulation.
2Reliability
If the conductor is earthed to enable leakage current detection, then accidental contact can be detected, but stray currents in the ground cause false detections
Solution Approach 1:
The patent extracts the earthed reference function from the ground itself and implements it through a dedicated third electrical conductor that is intentionally earthed at specific locations. This separation allows the system to create a controlled reference potential that is independent of the unpredictable stray currents in the ground, enabling accurate leakage detection without false alarms.
3Productivity
If a long bipolar rail is used to fully recharge the accumulator without stopping, then recharging efficiency improves, but the overall dimensions and infrastructure costs increase
Solution Approach 1:
The patent introduces guide rails that enable dynamic adjustment of the bipolar rail position and orientation. This dynamic capability allows the system to optimize the effective length and positioning of the bipolar rail based on vehicle location and charging needs, achieving efficient recharging without requiring excessively long fixed infrastructure.
4Adaptability or versatility
If guide rails with height more than 20 centimeters are used, then variations in vehicle height can be compensated, but the device complexity increases
Solution Approach 1:
The patent employs guide rails with sufficient height to create an equipotential reference plane that accommodates variations in vehicle height due to passenger load or platform adjustments. This height compensation mechanism maintains electrical contact reliability without requiring complex active adjustment systems, balancing adaptability with structural simplicity.
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
Enables reliable detection of accidental contacts, prevents false leakage current alarms, and reduces infrastructure costs by using a bipolar rail system that allows for continuous recharging without stopping and reduces accumulator size, enhancing safety and operational efficiency.
Implementation Method 1
a leakage currently develops between said conductor or collector shoe and the ground, through the body and the third conductor or collector shoe
Implementation Method 2
the fact that a floating power supply is used, i.e. one that is electrically insulated from the ground, prevents untimely detections of leakage current
Data Source
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Figure 5
AI summary
This public transport system comprises: - a bipolar rail comprising a third electrical conductor (134), which is earthed, and - an electric vehicle comprising a third collector shoe (138) connected to the body of the vehicle, said third collector shoe being suitable to rub against the third electrical conductor when the vehicle travels along the bipolar rail to connect the body to earth potential at the same time as the first and second collector shoes rub against the first and second electrical conductors of said bipolar rail.