Rail Traction Chain Solid-State Circuit Breakers
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Solution Overview
Problem
Conventional electric traction chains for railway vehicles rely on electromechanical components, which are unreliable, sensitive to environmental conditions, require frequent maintenance, and have slow reaction times, and include large input chokes and short-circuiters that are inefficient in managing overcurrents and overvoltages.
Innovation Solution
The implementation of a solid-state circuit breaker (SSCB) in place of electromechanical circuit breakers and isolation contactors, with static circuit-breaker contactors controlling current and voltage to manage overcurrents and overvoltages, and the removal of short-circuiters, reducing the size of input chokes and eliminating the need for preloading systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electromechanical circuit breakers and isolation contactors are used, then the traction chain can protect against overcurrents and isolate faulty branches, but the system suffers from low reliability, slow reaction time, high maintenance needs, and sensitivity to environmental conditions
Solution Approach 1:
The patent replaces electromechanical circuit breakers and isolation contactors with static circuit-breaker contactors that use electronic switching devices (such as IGBTs or thyristors) instead of mechanical moving parts. This substitution eliminates wear and tear, improves reliability, and enables much faster reaction times while reducing maintenance requirements and environmental sensitivity.
2Reliability
If input chokes are sized to withstand overcurrents and overvoltages, then the system can handle fault conditions, but the chokes become large in size
Solution Approach 1:
The patent replaces traditional electromagnetic overcurrent protection (which requires large inductors) with electronic overcurrent detection and static circuit-breaker contactors. The electronic system detects overcurrent conditions and opens the circuit rapidly, allowing the use of much smaller input chokes while maintaining the same protection level.
Solution Approach 2:
The patent changes the protection mechanism from passive electromagnetic inertia (large chokes) to active electronic control (fast-acting static circuit breakers). This parameter change allows the system to achieve the same protection function with significantly reduced component sizes by using electronic switching speeds rather than electromagnetic time constants.
3Reliability
If short-circuiters are used to avoid overvoltages, then the system can protect against voltage spikes, but the system complexity increases and efficiency decreases
Solution Approach 1:
The patent replaces mechanical or electronic short-circuiters with static circuit-breaker contactors that can rapidly open to isolate faults. This electronic switching approach provides overvoltage protection through controlled isolation rather than passive short-circuiting, reducing system complexity and improving efficiency while maintaining protection capabilities.
Data Source
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AI summary
The chain has a pantograph (4) for collecting electric energy on a feeder i.e. catenary system (2). Traction casings (18) have three-phase static traction converters (38) for supplying the electric energy to electric motors (6), respectively. Static circuit breakers (201-203) are arranged between the pantograph and the traction casings, respectively. The circuit breakers are controlled for being opened, when the current traversing the respective circuit breakers attains a predetermined threshold.