Siemens SIPROTEC 5 7SS85 Busbar Protection Relay

Siemens SIPROTEC 5 7SS85 Busbar Protection Relay Suppliers,Exporters in India

ARP IMPEX is a supplier and exporter of Siemens SIPROTEC 5 7SS85 Busbar Protection Relays in India. We handle requirements for utility substations, industrial power systems, power-plant switchyards, new protection panels, substation extensions and replacement of older Siemens busbar protection systems.

The Siemens 7SS85 provides low-impedance differential protection for busbars in medium-voltage, high-voltage and very-high-voltage networks. It detects a fault within the busbar area and trips the circuit breakers connected to the affected zone while keeping the healthy bus sections in operation.

A busbar fault can involve a very high short-circuit current and may affect several feeders at the same time. The protection system therefore has to operate quickly, identify the correct bus zone and avoid unnecessary tripping during faults outside the protected area. The 7SS85 uses phase-selective measurement, separate check zones and fast differential algorithms for this purpose.

The relay can be built around a centralised, distributed or hybrid architecture. In a centralised arrangement, the current and switching information comes directly to the central 7SS85 device. A distributed system uses bay devices or merging units to collect information closer to each feeder. The hybrid option allows both methods within the same busbar protection scheme.

This flexibility makes the Siemens SIPROTEC 7SS85 suitable for new substations as well as extensions and modernisation of existing protection systems. It can also form part of a replacement plan for the older Siemens SIPROTEC 7SS52 busbar protection platform.

For Siemens SIPROTEC 7SS85 price and availability against an existing requirement, share the complete Siemens part number, required quantity and destination country.

Technical Specifications

• Brand: Siemens
• Product family: SIPROTEC 5
• Model: 7SS85
• Product type: Low-impedance busbar differential protection relay
• Voltage application: Medium-, high- and very-high-voltage systems
• Protection architecture: Centralised, distributed or hybrid
• Measurement: Phase-selective current measurement
• Tripping: Selective tripping of the affected bus zone
• Check zone: Disconnector-independent check zone
• Centralised tripping time: 3 ms or 7 ms, depending on relay output type
• Distributed tripping time: 8 ms or 12 ms, depending on relay output type
• Current transformers: Support closed-core and linearised CT arrangements
• CT ratios: Different ratios can be adapted through parameter settings
• Breaker failure protection: Integrated one-pole/three-pole or three-pole functions
• End-fault protection: Available for feeder and bus-coupler sections
• Bus-coupler protection: Differential protection for couplers with two CTs
• Engineering software: Siemens DIGSI 5
• Communication: IEC 61850-compatible station and process-bus options
  Time synchronisation: IEEE 1588 PTP Grandmaster Clock function
• Cybersecurity: Role-based access, security-event logging, signed firmware and IEEE 802.1X support
• Hardware: Modular and scalable SIPROTEC 5 construction

The final hardware arrangement depends on the number of bays, bus zones, CT inputs, binary contacts, communication architecture and required redundancy. The description “Siemens 7SS85” alone does not identify one standard device configuration.

Main Protection Functions

Depending on the designed scheme, the Siemens SIPROTEC 7SS85 can provide:

• Phase-selective busbar differential protection
• Selective tripping of faulty bus zones
• Disconnector-independent check-zone supervision
• Sensitive protection for low-current internal faults
• Stabilisation during external faults and CT saturation
• Integrated circuit-breaker failure protection
• End-fault protection
• Bus-coupler differential protection
• Direct tripping of selected protection zones
• Phase-selective external trip release
• Cross-stabilisation for transformer-related secondary currents
• Monitoring of current-transformer circuits
• Supervision of measured-value acquisition
• Trip-circuit monitoring
• Blocking of individual bays or protection zones
• Processing of circuit-breaker and disconnector positions

The 7SS85 uses several interacting measurement methods to achieve fast internal-fault detection while maintaining stability during large through-fault currents. Siemens states that the algorithm requires only a short saturation-free period from the current transformers to distinguish internal and external faults.

Features

• Fast and selective clearance of busbar faults
• Suitable for MV, HV and very-high-voltage substations
• Centralised, distributed and hybrid architecture options
• Supports single-to five-busbar arrangements
• Suitable for breaker-and-a-half schemes
• Supports double circuit-breaker and ring-bus arrangements
• Can be used with truck-type switchgear
• Protects H-configurations and combined busbar schemes
• Phase-selective measurement and tripping
• A separate check zone improves tripping security
• Remains stable during external faults and CT saturation
• Adjustable differential operating characteristics
• Works with different current-transformer ratios
• Integrated breaker failure and end-fault protection
• Modular hardware can be matched to the number of bays and zones
• IEC 61850 supports distributed and digital-substation schemes
• Process-bus support allows connection with merging units
• DIGSI 5 provides graphical engineering and plant visualisation
• Redundant communication can be included where required
• Suitable for replacement of older Siemens 7SS52 systems

Siemens supports a wide range of busbar layouts, including single to five-way busbars, breaker-and-a-half systems, dual-breaker schemes, ring busbars, H arrangements and truck-type switchgear.

Busbar Protection Arrangements

Centralised Busbar Protection

A centralised arrangement brings the required CT currents, breaker positions and disconnector signals to the central 7SS85 system. This approach can suit substations where the panel wiring and equipment layout allow the complete protection system to be concentrated in one location.

Distributed Busbar Protection

In a distributed arrangement, bay devices collect current values and switching information from individual feeders. The information is then exchanged with the central busbar protection over an IEC 61850 communication system.

Applicable modular SIPROTEC 5 devices and merging units can work as bay-level equipment in this architecture.

Hybrid Busbar Protection

The hybrid arrangement combines direct hardwired inputs and information received from distributed bay devices. It can be useful where part of the substation follows conventional wiring and another part uses process-bus communication.

The correct architecture depends on the existing substation, approved utility standard, number of bays, communication design and expansion plans.

Applications

Siemens SIPROTEC 5 7SS85 Busbar Protection Relays are used for:

• Medium-voltage busbar protection
• High-voltage transmission substations
• Very-high-voltage substations
• Utility distribution substations
• Utility transmission switchyards
• Power-generation switchyards
• Industrial substations
• Captive power plants
• Air-insulated switchgear substations
• Gas-insulated switchgear substations
• Single-busbar schemes
• Double-busbar schemes
• Multiple-busbar arrangements
• Main and transfer bus schemes
• Breaker-and-a-half substations
• Double circuit-breaker schemes
• Ring-bus arrangements
• H-bus configurations
• Truck-type medium-voltage switchgear
• Substation extensions
• Digital substation projects
• IEC 61850 process-bus systems
• Replacement of Siemens SIPROTEC 7SS52 systems
• Busbar protection-panel modernisation

The 7SS85 is particularly relevant for substations where a busbar fault must be cleared quickly without disconnecting more feeders than necessary. It also suits projects that need to combine conventional wiring with distributed bay-level measurement and IEC 61850 communication.

Siemens 7SS52 Replacement with 7SS85

The SIPROTEC 7SS85 can be considered when an existing Siemens 7SS52 busbar protection system requires replacement or modernisation. However, it should not be treated as a simple plug-in replacement.

A busbar protection upgrade may involve:

• Review of the existing busbar single-line diagram
• Number of bus zones and connected bays
• Current-transformer arrangement and ratios
• Breaker and disconnector position signals
• Existing central and bay units
• Trip circuits and breaker failure logic
• Communication architecture
• Existing panel space and wiring
• Required redundancy
• IEC 61850 station-bus or process-bus integration

The 7SS85 supports centralised, distributed and hybrid solutions, which allows the replacement design to follow the condition of the existing system rather than forcing one architecture for every project.

Information Required for Quotation

For an exact spare or replacement enquiry, share:

• Complete Siemens article number or MLFB
• Required quantity
• Destination country
• For a new busbar protection system or where the article number is unavailable, share:
• Substation single-line diagram
• Number of busbar zones
• Number of feeder and coupler bays
• Busbar configuration
• Centralised, distributed or hybrid requirement
• Current-transformer details
• IEC 61850 or process-bus requirement
• Existing relay model, where applicable

A busbar protection system cannot be selected accurately only from the system voltage. The number of bays, bus zones, CT inputs, switching arrangement, and trip logic directly affect the required 7SS85 hardware.

Siemens SIPROTEC 5 7SS85 Supplier and Exporter in India

ARP IMPEX supplies Siemens SIPROTEC 5 7SS85 Busbar Protection Relays for utilities, EPC contractors, switchgear manufacturers, protection-panel builders, power plants and industrial users.

We handle enquiries for Siemens 7SS85 low-impedance busbar protection, centralised busbar protection systems, distributed IEC 61850 busbar protection, breaker-and-a-half schemes, substation extensions and replacement of Siemens 7SS52 systems.

The Siemens SIPROTEC 7SS85 price depends on the complete hardware configuration, number of bays and zones, CT inputs, binary I/O, communication architecture, redundancy and ordered quantity.

Send the complete Siemens part number, quantity and destination country for price, availability and export quotation. For a new system without an article number, share the busbar single-line diagram and protection requirement.