Siemens Reyrolle 7SR18 Solkor Line Differential Protection Relay

Siemens Reyrolle 7SR18 Solkor Line Differential Protection Relay Suppliers,Exporters in India

ARP IMPEX supplies and exports Siemens Reyrolle 7SR18 Solkor Line Differential Protection Relays for underground cable feeders, overhead lines, industrial substations and medium-voltage protection panels. The relay is supplied against the required Siemens article number, communication arrangement and project specification.

The Siemens Reyrolle 7SR18 is a numerical protection relay designed for two-terminal lines and cable circuits. One relay is installed at each end of the protected feeder. The two relays compare current measurements and quickly isolate faults occurring between the line ends.

The 7SR18 is commonly selected for underground cable protection, short overhead lines, industrial interconnectors and critical feeders where fast and selective fault clearance is required. It also provides backup overcurrent and earth-fault protection if the differential communication channel becomes unavailable.

The relays communicate through a fibre-optic connection. Multimode fibre can be used for shorter links, while single-mode fibre suits longer line-protection distances. Depending on the selected version, the relay can also support serial communication, Ethernet and IEC 61850 integration.

Buyers looking for a Siemens Reyrolle 7SR18 supplier in India, a line differential protection relay exporter, or a numerical relay for underground cable protection can send the complete ordering code, line length, CT details and fibre requirement for price and availability.

Technical Specifications

• Brand: Siemens
• Product family: Reyrolle
• Series: 7SR18 Solkor
• Product type: Numerical line differential protection relay
• Main application: Protection of two-terminal overhead lines and underground cables
• Protection arrangement: One relay is installed at each end of the protected line
• Differential protection: Three-phase, phase-segregated current differential protection
• Current inputs: Four
• CT secondary options: 1 A and 5 A
• Voltage inputs: Three
• Binary inputs and outputs depend on the selected relay configuration
• Fibre communication: Multimode or single-mode fibre
• Protection distance: Up to approximately 40 km, depending on the fibre arrangement
• Display: Front LCD with navigation controls
• Indication: Programmable front LEDs
• Local communication: Front USB port
• Remote communication: RS485 on applicable models
• Ethernet options: Electrical or optical Ethernet, depending on the version
• Communication protocols: IEC 60870-5-103, Modbus RTU, DNP3 and optional IEC 61850
• Network redundancy: PRP, HSR and RSTP on selected Ethernet versions
• Construction: Withdrawable relay design
• Configuration software: Siemens Reydisp Evolution
• Recording functions: Fault, event and waveform recording
• Control functions: Intertripping, autoreclosing and circuit-breaker control

The number of binary inputs, outputs and communication interfaces depends on the complete Siemens article number. Both relays used in the protection scheme must be selected for the required CT arrangement and fibre-optic communication link.

Main Protection Functions

Depending on the selected configuration, the Siemens Reyrolle 7SR18 can provide:

• Line differential protection
• Phase overcurrent protection
• Earth-fault protection
• Directional overcurrent protection
• Directional earth-fault protection
• Negative-phase-sequence protection
• Thermal overload protection
• Undercurrent protection
• Switch-onto-fault protection
• Circuit-breaker failure protection
• CT and VT supervision
• Trip-circuit supervision
• Close-circuit supervision
• Intertripping
• Automatic reclosing
• Communication-channel supervision

The integrated overcurrent and earth-fault elements provide backup protection when the fibre communication link is unavailable. This reduces the need for a separate backup feeder relay in many applications.

Fibre-Optic Communication Options

The two 7SR18 relays exchange protection and tripping information through a dedicated fibre-optic link.

Multimode fibre is generally used for shorter connections within a plant or substation. Single-mode fibre is selected for longer feeders and inter-substation links. The relay continuously monitors the communication channel and can provide an alarm if the fibre link fails.

The exact fibre type, distance, connector and communication interface should be confirmed before ordering. Buyers replacing an existing 7SR18 should share the full relay part number and details of the installed fibre network.

Features

• Provides fast protection for internal line and cable faults
• Suitable for two-terminal feeders and interconnectors
• Protects underground cables and overhead lines
• Phase-segregated operation helps identify the faulted phase
• Integrated overcurrent and earth-fault functions provide backup protection
• Supports multimode and single-mode fibre connections
• Continuous fibre-link supervision identifies communication failures
• CT ratio compensation can support different CT ratios at the two line ends
• Intertripping allows the relay to operate the remote circuit breaker
• Automatic reclosing is available for suitable overhead-line applications
• Circuit-breaker failure protection supports backup fault clearance
• Front LCD provides access to measurements, settings and fault information
• Programmable LEDs give clear trip and alarm indication
• Event and waveform records help with post-fault investigation
• Front USB connection simplifies commissioning and settings transfer
• Serial and Ethernet communication options support SCADA integration
• IEC 61850 versions suit digital substation projects
• Withdrawable construction makes testing and replacement easier
• Suitable for new protection panels and retrofit projects

Applications

Siemens Reyrolle 7SR18 Line Differential Protection Relays are commonly used for:

• Underground medium-voltage cable feeders
• Overhead distribution lines
• Two-terminal transmission and distribution lines
• Industrial plant interconnectors
• Parallel feeder circuits
• Incoming and outgoing substation feeders
• Utility distribution substations
• Power-generation auxiliary feeders
• Solar and wind power evacuation feeders
• Oil and gas electrical networks
• Refinery and petrochemical substations
• Steel and cement plant distribution systems
• Mining and mineral-processing facilities
• Water and wastewater plants
• Railway and metro power systems
• Data-centre electrical distribution networks
• Critical industrial power feeders
• Protection-panel retrofit projects
• Replacement of older pilot-wire protection relays

The 7SR18 is suitable for projects requiring a fibre-optic line differential protection relay, a two-ended cable protection relay, or a numerical feeder differential relay with IEC 61850 communication.

Selecting the Correct Siemens 7SR18 Relay

The Reyrolle 7SR18 should not be selected only by the series name. The relays installed at both line ends must match the CT circuits, communication link, breaker arrangement and substation control system.

For accurate selection and quotation, provide:

• Complete Siemens article number
• Underground cable or overhead-line application
• System voltage
• Line or cable length
• Rated feeder current
• CT ratios at both ends
• CT secondary current
• VT ratio
• Auxiliary supply voltage
• Required binary inputs and outputs
• Multimode or single-mode fibre requirement
• Available fibre cores and connector types
• IEC 61850 or serial communication requirement
• Electrical or optical Ethernet requirement
• Automatic reclosing requirement
• Circuit-breaker details at both ends
• Quantity and destination country

For replacement enquiries, share clear photographs of the existing relay nameplate, panel wiring diagram, fibre details and setting files where available.

Siemens Reyrolle 7SR18 Supplier and Exporter in India

ARP IMPEX is an independent supplier and exporter of Siemens Reyrolle protection relays in India. We supply Reyrolle 7SR18 Line Differential Protection Relays for utilities, EPC contractors, switchgear manufacturers, panel builders and industrial maintenance companies.

We handle requirements for:

• Siemens Reyrolle 7SR18 line differential relays
• Underground cable differential protection relays
• Overhead-line protection relays
• Fibre-optic feeder protection relays
• IEC 61850 line differential relays
• Reyrolle protection relay replacement requirements
• MV substation protection panel projects

The Siemens 7SR18 price depends on the complete article number, communication interface, binary I/O arrangement and fibre requirement. Quotations should therefore be based on the exact ordering code rather than only the description “7SR18 relay.

For price and export availability, share the complete Siemens part number, CT details, fibre requirement, quantity and delivery country.