DC / battery converter protection

DC systems and batteries — dedicated protection and monitoring

DC systems in substations (110/220 V auxiliary supply), battery energy storage installations (BESS), DC traction systems and hybrid vessel power architectures need a different protection device family than AC systems. Direct DC current and voltage measurement, shunt and transducer inputs, polarity-aware fault logic and an interface to the battery management system (BMS) define the application.

SYMAP^® is not a BMS replacement. SYMAP^® Y-BAT and Y-DC variants provide DC-side protection (overcurrent, earth-fault, undervoltage, insulation, breaker control) and a signal and communication interface to the BMS over Modbus or IEC 61850.

Typical DC applications

Substation auxiliary DC

110 V or 220 V DC auxiliary supply for substations. Battery and charger monitoring, insulation supervision, automatic transfer between two charger groups.

BESS — battery storage

Grid-connected battery storage installations. DC monitoring on the battery side (Y-BAT), AC grid connection through Compact+ GC with NA protection and Grid Code logic.

Hybrid vessels

Diesel + battery + converter architectures, DC and AC bus sections, peak shaving, spinning reserve reduction. Signal interface to the BMS, not a BMS replacement.

DC traction supply

DC substations for rail and metro traction (750 V, 1500 V, 3000 V). High-speed DC fault protection, rectifier monitoring, regenerative-braking integration.

Solar plant DC side

String-level and combiner-box monitoring in utility-scale PV plants. Insulation supervision, ground-fault detection, arc-fault detection on the DC side.

HVDC interfaces

Auxiliary protection and monitoring on HVDC converter stations. Project-specific configurations with extended I/O through CMA and EBS modules.

Compact+ or classic SYMAP^®?

Classic SYMAP^® Y-DC / Y-BAT is the dedicated variant for DC and battery applications with DC measurement, shunt/transducer inputs and an interface to BMS and SCADA. SYMAP^® Compact+ GC applies to the AC grid connection of BESS installations (NA protection, Grid Code). SYMAP^® is not a BMS replacement, it provides a signal and communication interface to the BMS.

Products covering DC applications

Need detailed technical specifications?

For exact protection function coverage, settings ranges, DC measurement specifications, shunt/transducer interface, BMS communication protocols and configuration support, contact our team to receive the relevant datasheet and engineering proposal.

Request datasheet Engineering inquiry

DC system and battery protection