Busbar protection SIPROTEC 7SS52

Busbar protection SIPROTEC 7SS52

Product Overview

The SIPROTEC 7SS52 numerical protection is a selective, reliable and fast protection for busbar faults and breaker failure in medium, high and extra-high voltage substations with various possible busbar configurations.

Features :

The protection is suitable for all switchgear types with iron-core or linearized current transformers. The short tripping time is especially advantageous for applications with high fault levels or where fast fault clearance is required for power system stability.

The modular hardware allows the protection to be optimally matched to the busbar configuration. The decentralized arrangement allows the cabling costs in the substation to be drastically reduced. The SIPROTEC 7SS52 busbar protection caters for single, double or triple busbar systems with or without and quadruple busbar systems without transfer bus with up to: 48 bays, 16 bus couplers, and 24 sectionalizing disconnectors and 12 busbar sections.

Communication interfaces

  • FO interface
    – IEC 60870-5-103
  • Electrical interface
    – IEC 61850

Functions :

Busbar protection functions

  • Busbar differential protection
  • Selective zone tripping
  • Very short tripping time (<15 ms)
  • Extreme stability against external fault, short saturation-free time (≥2 ms)
  • Phase-segregated measuring systems
  • Integrated check zone
  • 48 bays can be configured
  • 12 busbar sections can be protected
  • Bay-selective intertripping

Breaker failure protection functions

  • Breaker failure protection (single-phase with/without current)
  • 5 operation modes, selectable per bay
  • Separate parameterization possible for busbar and line faults
  • Independently settable delay times for all operation modes
  • 2-stage operation bay trip repeat/trip busbar
  • Intertrip facility (via teleprotection interface)
  • “Low-current” mode using the circuitbreaker auxiliary contacts

Additional protection functions

  • End-fault protection with intertrip or bus zone trip
  • Backup overcurrent protection per bay unit (definite-time or inverse-time)
  • Independent breaker failure protection per bay unit


  • Distributed or centralized installation
  • Easy expansion capability
  • Integrated commissioning aids
  • Centralized user-friendly configuration/parameterization with DIGSI
  • Universal hardware

More Information


+66 2 063 5262-3, +66 83 440 1404