Busbar Protection SIPROTEC 7SS85

The SIPROTEC 7SS85 busbar protection device provides  selective, safe, and fast protection against busbar short circuits in medium-voltage systems, high-voltage systems, and systems for very high voltage with different busbar configurations. It can be tailored to suit a wide variety of system configurations and functional requirements up to a complete station protection using its device base functionalities (significant features) and modular hardware structure.

The proven, fast, and safe algorithms used by the phased-out SIPROTEC 4 7SS52 coupled with the flexible, scalable, open, and user-friendly SIPROTEC 5 platform set the new standard for busbar protection SIPROTEC 7SS85.

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DESCRIPTION

Basic Features

  • Phase-selective measurement and display
  • Selective tripping of faulty bus zones
  • Disconnector-independent check zone as additional tripping criterion
  • Shortest tripping times to ensure network stability and minimize damage to the system

        - Central busbar protection: 3 ms/7ms (Relais Typ HS/Typ F)

        - Decentral busbar protection: 8 ms/12 ms (Relais Typ HS/Typ F)

  • Highest stability in case of external faults – even in case of transformer saturation – through stabilization
  • with flowing currents
  • Operate curve with freely adjustable characteristic curve sections
  • Additional operate curve with increased sensitivity for low-current errors (e.g. in resistance-grounded power systems)
  • Fast recognition of internal and external errors requires only 2 ms of saturation-free time of the current transformer
  • Three interacting methods of measurement allow minimum tripping times after busbar faults and ensure maximum stability in case of large short-circuit currents
  • The integrated circuit-breaker failure protection recognizes circuit breaker faults in the event of a busbar short circuit and provides a trip signal for the circuit breaker at the line end (the adjacent busbar trips if a coupling circuit breaker fails)
  • There is extensive monitoring of current transformer circuits, measured value acquisition and processing, and trip circuits which prevents the protection from subfunction, which reduces the effort for routine checks.
  • 1/3-pole or 3-pole circuit-breaker failure protection using the integrated disconnector image for tripping all circuit breakers of the busbar section affected
  • End-fault protection for the protection of the section between circuit breaker and current transformer for feeders and bus couplers
  • With decentralized busbar protection, any feeder protection function can be additionally implemented by using any modular SIPROTEC 5 device as a bay device
  • Extensive cybersecurity functionality (e.g. as role-based access control (RBAC), protocolling security-related events, signed firmware or authenticated network access IEEE 802.1X)