SIEMENS SIPROTEC 4 SIPROTEC 7SS52 DISTRIBUTED BUS BAR DIFFRENTIAL PROTECTION RELAY

The SIPROTEC 7SS52 numerical protection is a selective, reliable andfast protection for busbar faults and breaker failure in medium, high andextra-high voltage substations with various possible busbar configurations.Theprotection is suitable for all switchgear types with iron-core or linearizedcurrent transformers. The short tripping time is especially advantageous forapplications with high fault levels or where fast fault clearance is requiredfor power system stability.The modular hardware allows the protection to beoptimally matched to the busbar configuration. The decentralized arrangement allowsthe cabling costs in the substation to be drastically reduced. The 7SS52 busbarprotection caters for single, double or triple busbar systems with or withoutand quadruple busbar systems without transfer bus with up to: 48 bays, 16 buscouplers, and 24 sectionalizing disconnectors and 12 busbar sections.

BUSBAR PROTECTION FUNCTIONS1.    Busbar differential protection2.    Selective zone tripping3.    Very short tripping time(<15 ms)4.    Extreme stability againstexternal fault, short saturation-free time (2 ms)5.    Phase-segregated measuringsystems6.    Integrated check zone7.    48 bays can be configured8.    12 busbar sections can beprotected9.    Bay-selective intertripping 

BREAKER FAILURE PROTECTIONFUNCTIONS1.    Breaker failure protection(single-phase with/without current)2.    5 operation modes, selectableper bay3.    Separate parameterizationpossible for busbar and line faults4.    Independently settable delaytimes for all operation modes5.    2-stage operation bay triprepeat/trip busbar6.    Intertrip facility (viateleprotection interface)7.    Low-current mode using thecircuit breaker auxiliary contacts 

ADDITIONAL PROTECTION FUNCTIONS1.    End-fault protection withintertrip or bus zone trip2.    Backup overcurrent protectionper bay unit (definite-time or inverse-time)3.    Independent breaker failureprotection per bay unit 

FEATURES1.    Distributed or centralizedinstallation2.    Easy expansion capability3.    Integrated commissioning aids4.    Centralized user-friendlyconfiguration/parameterization with DIGSI5.    Universal hardware                              

COMMUNICATION INTERFACES1.    FO interface IEC 60870-5-103 protocol

2.    Electrical interface
IEC 61850 protocol with EN 100 module (firmware V4.6)