Siemens SIPROTEC 5 7SD87 Line Differential Protection Relay
Siemens SIPROTEC 5 7SD87 Line Differential Protection Relay Suppliers,Exporters in India
ARP IMPEX is a supplier and exporter of Siemens SIPROTEC 5 7SD87 Line Differential Protection Relays in India. We handle requirements for high-voltage transmission lines, underground cable circuits, grid interconnections, utility substations, protection-panel upgrades and replacement of existing Siemens relays.
The Siemens 7SD87 is mainly selected for important lines where the protection scheme requires phase-selective differential protection. It supports both one-pole and three-pole tripping, allowing the system to disconnect only the faulted phase during an applicable single-phase fault instead of opening the complete three-phase circuit.
This feature makes the 7SD87 particularly useful for overhead transmission lines where temporary phase-to-earth faults may occur. In a properly designed scheme, the relay can trip the affected phase, start a single-pole reclosing cycle and keep the healthy phases in operation. The relay supports one-pole automatic reclosing with secondary arc detection.
Line differential protection compares the current measurements received from both ends of the protected circuit. When the calculated differential current indicates an internal fault, the relay initiates fast and selective tripping. Siemens specifies a minimum tripping time of 9 ms for the 7SD87.
The relay can cover overhead lines, underground cables and routes containing both types. It supports single-ended and multi-ended networks with up to six line ends. Transformers and compensating coils can also remain inside the protected differential zone when the approved protection scheme requires it.
Its adaptive differential algorithm takes into account current-transformer errors, CT saturation and capacitive charging current. This helps maintain sensitivity for internal faults without causing unwanted trips during heavy external faults or normal cable-charging conditions.
For Siemens SIPROTEC 7SD87 price and availability, share the complete Siemens article number, required quantity and destination country.
Technical Specifications
- Brand: Siemens
- Product family: SIPROTEC 5
- Model: 7SD87
- Product type: Modular line differential protection relay
- Main application: Selective protection of overhead lines and cables
- Network application: Lines across different voltage levels
- Primary protection: Phase-selective line differential protection
- Tripping arrangement: One-pole and three-pole
- Minimum tripping time: 9 ms
- Line arrangement: Single-ended and multi-ended circuits
- Maximum line ends: Up to six
- Standard hardware options: 12 predefined variants
- Analogue inputs: 4 CT/4 VT or 8 CT/8 VT arrangements
- Binary inputs: 5 to 31, depending on hardware
- Binary outputs: 8 to 46, depending on hardware
- Hardware construction: Modular and expandable
- Housing width: From one-third to two full 19-inch rack widths
- Engineering software: Siemens DIGSI 5
- Communication: Ethernet, optical fibre, two-wire and network options
- Communication modules: Up to four optional plug-in modules
- IEC 61850: Reporting and GOOSE communication
- Redundancy: PRP and HSR on applicable configurations
- Environmental protection: Conformal-coated electronic modules
The complete hardware, auxiliary supply, input and output arrangement, display, communication interfaces and enabled functions depend on the Siemens MLFB.
Main Protection Functions
- The available protection package can include:
- Phase-selective line differential protection
- Negative-sequence differential protection
- Ground-current differential protection
- Directional backup protection
- Phase and earth-fault protection
- Sensitive ground-fault detection
- Ground-fault detection using the pulse method
- Current-transformer saturation detection
- Charging-current compensation
- Fault Locator Plus
- One-pole and three-pole automatic reclosing
- Secondary arc detection
- Targeted overhead-line section reclosing
- Arc protection
- Point-on-wave switching
- Voltage and frequency monitoring
- Programmable trip, alarm and interlocking logic
Negative-sequence differential protection provides greater sensitivity for unbalanced faults, including phase-to-phase faults. Ground-current differential protection can remain sensitive even when a high balanced load current flows through the protected circuit. The enabled functions still depend on the ordered relay configuration.
Features
- One-pole and three-pole tripping for phase-selective line protection
- Fast operation with a minimum tripping time of 9 ms
- Protects overhead lines, underground cables and mixed routes
- Supports two-terminal and multi-terminal protection schemes
- Suitable for lines with up to six ends
- Adaptive differential protection improves stability and sensitivity
- Compensates for the capacitive charging current on long cable circuits
- Detects CT saturation during heavy through-fault conditions
- Negative-sequence protection improves the detection of unbalanced faults
- Ground-current differential protection supports sensitive earth-fault detection
- Single-pole automatic reclosing available for overhead-line schemes
- Fault Locator Plus helps identify the affected line section
- Transformers and compensating coils can remain within the protection zone
- Suitable for breaker-and-a-half switchgear arrangements
- Expandable inputs and outputs suit larger protection panels
- Up to four communication modules can be selected
- Supports communication with applicable SIPROTEC 4 and SIPROTEC 5 devices
- IEC 61850, PRP and HSR options support substation communication
- Conformal coating supports demanding substation conditions
- Suitable for new projects, panel extensions and relay replacement
Siemens also provides fault recording, PMU and basic power-quality functions on applicable configurations, but these are secondary to the relay’s main line differential protection role.
Applications
Siemens SIPROTEC 5 7SD87 Line Differential Protection Relays are used for:
- High-voltage overhead transmission lines
- Extra-high-voltage transmission networks
- Underground power cable circuits
- Mixed overhead-line and cable routes
- Phase-selective line protection
- Single-pole tripping schemes
- Three-pole tripping schemes
- Two-terminal transmission lines
- Multi-terminal and tapped lines
- Circuits with up to six line ends
- Grid interconnection lines
- Ring and meshed power networks
- Breaker-and-a-half substations
- Utility transmission substations
- Power-generation substations
- Renewable-energy evacuation lines
- Wind-farm grid connections
- Solar power transmission links
- Lines with transformers inside the protection zone
- Circuits containing compensating coils
- Isolated-neutral networks
- Arc-suppression-coil grounded networks
- Substation extension projects
- Replacement of older Siemens line differential relays
The 7SD87 is particularly relevant where the utility specification calls for selective one-pole tripping, fast line differential protection and dependable communication between several line terminals.
Siemens 7SD86 and 7SD87 Difference
Both models provide modular line differential protection with expandable SIPROTEC 5 hardware and a minimum tripping time of 9 ms.
The main difference is the tripping arrangement:
- SIPROTEC 7SD86: Three-pole tripping
- SIPROTEC 7SD87: One-pole and three-pole tripping
The 7SD87 is generally selected for important overhead transmission lines requiring phase-selective tripping and single-pole automatic reclosing.
The 7SD86 may be sufficient for cable circuits and protection schemes that always open all three phases. Selection should follow the approved utility specification and protection drawing.
Siemens 7SD87 and 7SL87 Difference
The 7SD87 is centred on line differential protection with directional and other backup functions.
The 7SL87 combines line differential and distance protection within the same relay.
A project requiring independent distance protection as a second main protection function may therefore call for the 7SL87. Where pure line differential protection with phase-selective tripping is required, the 7SD87 may be the more appropriate choice.
Information Required for Quotation
“Siemens 7SD87” does not identify one fixed relay configuration. Different article numbers may have different analogue inputs, binary contacts, displays, communication modules and protection functions.
For an accurate quotation, share:
- Complete Siemens article number or MLFB
- Required quantity
- Destination country
- Required communication interface, where specified
- For replacement requirements, also send:
- Clear photograph of the existing relay nameplate
- Front-panel photograph
- Rear-terminal photograph
- Existing firmware details, where available
- Model installed at the end of every other line
- Existing protection communication medium
- Confirmation of one-pole or three-pole tripping
Compatibility between the relays installed at different line ends must be confirmed before replacement. The physical communication medium and protection-interface arrangement must also match the existing scheme.
Siemens supports serial protection communication with applicable SIPROTEC 4 and SIPROTEC 5 line devices over fibre, two-wire connections and communication networks.
Siemens SIPROTEC 5 7SD87 Supplier and Exporter in India
ARP IMPEX supplies Siemens SIPROTEC 5 7SD87 Line Differential Protection Relays for utilities, transmission companies, EPC contractors, switchgear manufacturers, protection-panel builders and power plants.
We handle requirements for Siemens 7SD87 phase-selective line differential relays, single-pole transmission-line protection, multi-terminal line protection, underground cable protection, IEC 61850 line relays and replacement of existing Siemens numerical relays.
The Siemens SIPROTEC 7SD87 price depends on the complete article number, analogue inputs, binary I/O, housing arrangement, communication modules, enabled protection functions and required quantity.
Send the complete Siemens part number, quantity and destination country for price, availability and export quotation.
