Railway transformer protection. Reinvented
Fast differential logic. Smarter bay control. Rock-solid reliability every mile.
Explore MoreTraction transformers take the hardest hits. Your relay must take none
Aging relays miss inrush conditions, struggle with multi-frequency grids, misread CT asymmetries, and risk unwanted trips during through-faults. For a rail transformer, even one wrong operation can mean delays, downtime, and system-wide instability.
Purpose-built for traction transformers. Tuned for rail conditions
MiCOM P638 is a dedicated transformer differential relay engineered for AC railway substations. It protects two-winding traction transformers with fast DIFF elements, inrush restraint, vector group compensation, and backup distance + overcurrent protection. With integrated bay control for up to 10 switchgear units, it merges protection, monitoring, and control into a single, rugged, modular device — built specifically for the demands of rail traction power.
Protection built around traction transformers
From inrush restraint to high-security differential logic — P638 keeps rail transformers safe, stable, and online.
True transformer differential protection
HV–LV matching, vector group compensation, and harmonic restraint for stable, selective tripping
Through-fault stability when it matters
High-security bias ensures the relay stays quiet during heavy external faults.
Built-in feeder backup
Three-zone distance and directional overcurrent deliver backup protection without extra relays
Voltage & frequency clarity
Over/under-voltage and frequency elements secure sensitive railway power systems.
Thermal protection that thinks ahead
Advanced thermal modelling with optional PT100 coolant temperature
Complete bay control inside
Operate breakers, disconnectors, and earthing switches — all interlocked and validated.
Precision engineering. Railway endurance
High-security differential protection paired with robust I/O and advanced comms
Where MiCOM P638 makes the difference
Made for traction transformers. Ready for complex bay architectures
Engineered for rail. Reliable everywhere else
Perfect for railway traction power — adaptable to any DIFF-centric substation.
Railways & Metro Traction Networks
Transformer Protection Scope
Designed for traction transformer differential protection, backup feeder protection, and integrated HV/LV bay control in railway and mixed-voltage substations
Services
Relay Testing, Programming & Configuration
Complementary Transformer Protection Solutions
Compatible protection relays, communication modules, and bay-control components that strengthen coordinated transformer protection and operational reliability across rail power systems
Upgrade your transformer protection
Connect with our experts to deploy, configure, or modernise your railway transformers using MiCOM P638.
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