Railway Bus Breaker Control Circuit With Delay Reclosing Logic
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Solution Overview
Problem
Existing bus breaker control systems in subway vehicles face issues with frequent high-voltage circuit breaker closures, leading to reduced service life and increased costs, especially when the traction control unit fails or during zero velocity in non-power zones.
Innovation Solution
A bus breaker control circuit comprising a close relay, an open relay, power supply circuits for the bus breaker and hold relay, and a delay module, which optimizes the connection and disconnection of the high-voltage bus, reducing the frequency of high-voltage device use and allowing manual control, thereby extending the service life and lowering costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bus breaker is frequently closed with load during failures or zero velocity conditions, then the system maintains operational flexibility and current collection reliability, but the service life of the high-voltage circuit breaker is reduced and costs increase
Solution Approach 1:
The control circuit proactively manages breaker operation by using the delay module to prevent immediate reclosing after failure conditions, and by implementing speed-based prevention logic that keeps the breaker open during zero velocity conditions. This preliminary action avoids unnecessary breaker operations that would reduce service life while maintaining current collection reliability through alternative means.
2Ease of operation
If the bus breaker control is manually forced to close, then operational control and rescue capability are improved, but the frequency of high-voltage device use increases reducing its service life
Solution Approach 1:
The control circuit acts as an intermediary between manual commands and the actual breaker operation. It introduces intelligent mediation through speed detection and delay logic that can prevent or delay breaker closing even when manually commanded, thereby reducing unnecessary high-voltage device usage while preserving manual control capability for genuine operational needs.
3Device complexity
If the DCU directly controls the bus contactor box, then the control system is simple and responsive, but the system lacks redundancy and cannot operate when the DCU fails
Solution Approach 1:
The control circuit enables the bus breaker system to serve itself by incorporating autonomous failure detection and alternative control pathways. The circuit monitors DCU status and can independently execute breaker control decisions based on speed signals and failure conditions, allowing the system to maintain operation even when the DCU fails, thus improving reliability without significantly increasing complexity.
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 provides a simple and reliable internal current logic, reduces power consumption, and extends the service life of the bus breaker, while allowing controlled operation and manual intervention, thus lowering hardware costs and improving overall system reliability.
Implementation Method 1
a delay module RS; wherein a main contact of the bus breaker is connected to a circuit of a high-voltage bus and used for controlling connection/disconnection of the high-voltage bus; the power supply circuit for the hold relay comprises a normally-closed contact of the open relay, a first auxiliary normally-open contact of the bus breaker, and the hold relay which are sequentially connected in series to a train power supply; and the delay module is connected in parallel with the hold relay, normally-closed contacts of the delay module are connected in series to the power supply circuit for the close relay
Data Source
AI summary
A bus breaker control circuit for a railway vehicle includes a close relay, an open relay, a power supply circuit for a bus breaker, a power supply circuit for the hold relay, and a delay module; the power supply circuit for the hold relay comprises a normally-closed contact of the open relay, an auxiliary normally-open contact of the bus breaker, and the hold relay sequentially connected in series to a train power supply; the power supply circuit for the bus breaker comprises a normally-open contact of the hold relay and the bus breaker sequentially connected in series to the train power supply; and the delay module is connected in parallel with the hold relay, normally-closed contacts of the delay module are connected in series to the power supply circuit for the close relay.