Measurement is part of the traction-power protection architecture.
An electrified railway line behaves as a distributed power-conversion system. Energy from the public or dedicated grid is transformed, rectified where required, distributed through DC busbars and feeders, and finally delivered to the train through overhead line or third rail. Reliable current and voltage measurement supports protection selectivity, supply quality, energy management, diagnostics and network availability.
Fast overcurrent and short-circuit detection supports selective breaker operation.
Continuous voltage supervision helps verify operation inside the permitted traction-voltage envelope.
Feeder and substation current measurements help balance traction demand and monitor regenerative-energy flow.
Current and voltage trends can reveal progressive degradation before an outright failure.
Closed-loop Hall-effect current sensing
A magnetic core surrounds the primary conductor. A Hall element detects the magnetic flux in the air gap, while a compensation winding drives the net core flux toward zero. The resulting secondary current is proportional to the primary current and is galvanically isolated from the power circuit.
This principle combines wide bandwidth, good linearity and galvanic isolation, which are valuable in traction substations and onboard converters.
Typical DC substation architecture
Measurement points typically include transformer primary current, DC-bus or line voltage, and one current sensor per outgoing feeder. Feeder-current measurement is particularly important for protection selectivity so that only the faulted section is disconnected.
Typical AC traction substation architecture
Unlike the DC architecture, the traction power path does not include a rectifier. Current measurement remains important on the transformer primary and outgoing feeders, while voltage measurement supervises the traction bus and network interface.
Sensor families referenced for railway applications
Reference-level electrical performance and compliance must be checked on the applicable ADISENS datasheet.
Environmental and electrical constraints
| Reference | Area | Why it matters |
|---|---|---|
| EN 50155 | Electronic equipment on rolling stock | Environmental, electrical and reliability conditions |
| EN 61373 | Shock and vibration | Mechanical robustness of onboard equipment |
| EN 45545 | Fire behaviour | Fire and smoke requirements for railway applications |
| EN 50163 | Traction supply voltages | Defines traction-system voltage conditions |
Railway sensing also requires careful EMC design, galvanic isolation and controlled documentation because the measurement chain interfaces high-energy traction circuits with low-voltage protection and control electronics.
Translate the measurement requirement into the right sensing architecture.
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