Dynamic Breaker Closing for Train Reconnection
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Solution Overview
Problem
When multiple electrically powered train units on the same electrical power supply section detect a return to normal voltage and simultaneously close their breakers, it can lead to high electric current burdens on the power source, causing unrealistic loads due to synchronized inrush currents, which existing methods like fixed breaker closing time delays can inadequately manage, especially in large fleets.
Innovation Solution
A reconnection system that includes measuring devices in each train unit to detect power supply failures and recoveries, a supervision system connected to the breakers, and a delay generating system to dynamically determine and provide unique breaker closing times for each train unit, allowing for variable and optimized reconnection times to avoid simultaneous closures and reduce peak loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fixed breaker closing time delays are allocated to each train unit, then simultaneous breaker closures are prevented, but trains with long delays may unnecessarily miss schedules when few other trains are present
Solution Approach 1:
The breaker closing time delay is changed from a fixed value to a dynamic value that adjusts based on real-time conditions. The delay generating system receives information about the number of other trains in the fleet and dynamically determines the appropriate delay time. When few trains are present, the delay is reduced or eliminated; when many trains are present, the delay is increased to prevent simultaneous closures. This dynamic adjustment resolves the contradiction by making the delay adaptive to actual system conditions.
2Productivity
If breaker closing delays are reduced to maintain train schedules, then train timeliness improves, but simultaneous breaker closures may occur causing high inrush currents
Solution Approach 1:
The system implements feedback by having the delay generating system continuously monitor the number of trains in the fleet and use this information to adjust breaker closing delays. The supervision system receives train count information and feeds it back to dynamically determine appropriate delay values. This feedback mechanism allows the system to maintain short delays (for timeliness) when few trains are present, while automatically increasing delays when many trains are present to prevent simultaneous closures and harmful inrush currents.
3Productivity
If extemporaneous determination of breaker closing times is implemented, then optimal reconnection times are achieved, but system complexity increases due to dynamic delay generation
Solution Approach 1:
The delay generating system acts as an intermediary component that simplifies the overall system architecture. Rather than having each train unit independently calculate complex optimal closing times, the delay generating system receives simple inputs (train count, power supply status) and outputs pre-calculated delay values. This intermediary approach achieves optimal reconnection timing while keeping individual train unit complexity low, as the computational burden is centralized in the delay generating system.
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
This approach dynamically sets breaker closing times to prevent simultaneous reconnections, reducing the burden on the electrical power source and allowing for more efficient and timely train operations by avoiding unnecessarily long delays, thus optimizing the reconnection process.
Implementation Method 1
a measuring device to detect failure and recovery of power supply by the supply line
Implementation Method 2
a breaker to disconnect and reconnect traction equipment of the unit with the supply line
Implementation Method 3
the steady state of the transformer core's magnetic flux cannot be instantly accommodated and the steady state value is reached after a finite time determined by the rate at which the circuit can accept energy
Implementation Method 4
the primary coil of the transformer draws a high peak current known as the transformer inrush current
Data Source
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AI summary
A reconnection system is provided for reconnecting electrically powered train units to electrical power supply lines which extend along respective tracks of a rail network. The network is divided into plural power supply sections with each power supply section having a respective source of electrical power for the supply lines of the tracks in that section. The reconnection system includes plural of the train units, each unit having a measuring device to detect failure and recovery of power supply by the supply line of the track on which the unit is currently located, a breaker to disconnect and reconnect traction equipment of the unit with the supply line, and a supervision system which is operably connected to the measuring device and the breaker. The reconnection system further includes a delay generating system which is configured to extemporaneously determine a respective and different breaker closing time within a given power supply section for each of the train units on recovery of the power supply to the train units, and to provide the supervision systems of the train units with the respective breaker closing times thus-determined. Each supervision system is programed to: command its breaker to disconnect its traction equipment when its measuring device detects failure of the power supply; and after detection by the measuring device of recovery of the power supply, command the breaker to reconnect the traction equipment according to the breaker closing time for its train unit provided by the delay generating system. In this way, a breaker closing time delay at which any given one of the breakers is commanded to reconnect its traction equipment varies as between disconnection and reconnection events.