Siemens Reyrolle 7SR46 CT-Powered Overcurrent Protection Relay

ARP IMPEX supplies and exports Siemens Reyrolle 7SR46 CT-Powered Overcurrent Protection Relays for ring main units, medium-voltage switchgear, distribution substations and feeder protection panels. Buyers can share the complete Siemens article number, CT details and required quantity for price and export availability.

The Siemens Reyrolle 7SR46 is a numerical, non-directional overcurrent and earth-fault relay. It is mainly selected for installations where a dependable auxiliary power supply may not always be available. The relay can operate from the protection CTs and also accept an external auxiliary supply. This makes it suitable for RMUs, remote substations and secondary distribution networks.

The relay provides instantaneous and time-delayed protection against phase overcurrent and earth faults. Definite-time and inverse-time characteristics are available, allowing the protection engineer to coordinate the relay with upstream and downstream protection devices.

A stored-energy pulse output can operate a suitable circuit-breaker trip coil. Because the trip energy is stored inside the relay, the protection arrangement does not have to rely entirely on an external tripping supply during a fault. The exact circuit-breaker and trip-coil compatibility must still be checked during panel design.

The front LCD, navigation keys and LEDs allow engineers to view relay settings, current measurements and fault information at the panel. Settings and records can also be handled through the front USB port using Siemens Reydisp Evolution software. A rear RS485 port supports connection to compatible SCADA or remote monitoring systems.

Technical Specifications

• Brand: Siemens
• Product family: Reyrolle
• Series: 7SR46 Argus
• Product type: CT-powered overcurrent and earth-fault protection relay
• Protection direction: Non-directional
• Power arrangement: CT powered with provision for an external auxiliary supply
• Auxiliary supply range: 24–240 V DC or 60–240 V AC
• Current inputs: Three CT inputs
• CT requirement: Compatible specific wide-measuring-range protection CTs, Class 5P80
• Binary inputs: Two
• Binary outputs: Two, including the life contact
• Additional connections: External protection trip input, pulse trip output and trip-flag output
• Settings groups: Two
• Display: Two-line, 16-character backlit LCD
• Front indication: Two fixed LEDs and two programmable LEDs
• Local communication: Front USB port
• Remote communication: Rear RS485 port
• Protocols: IEC 60870-5-103 and Modbus RTU
• Fault records: Last 10 fault records
• Event records: Up to 100 time-tagged events
• Configuration software: Siemens Reydisp Evolution
• Construction: Flush-mounted polycarbonate housing
• Terminal options: Screw-type or push-in spring connections, depending on the ordered version
• Internal backup: Lithium battery for clock, records, settings display and indication reset when normal power is unavailable

The exact CT type, connection arrangement, terminal style and trip-flag option should be confirmed against the complete Siemens ordering code.

Protection Functions

The Reyrolle 7SR46 covers the main protection duties normally required in a compact secondary-distribution feeder or RMU panel:

• Instantaneous phase overcurrent protection
• Time-delayed phase overcurrent protection
• Instantaneous derived earth-fault protection
• Time-delayed derived earth-fault protection
• Definite-time and inverse-time operation
• Thermal overload protection
• Line check and switch-onto-fault protection
• Transformer inrush-current detection
• High-speed external trip input
• Protection lockout
• Current measurement and relay supervision

The switch-onto-fault function provides fast tripping when a circuit breaker closes onto an existing feeder fault. It can also respond where an earthing connection has accidentally remained in place after maintenance.

CT-Powered and Auxiliary-Powered Operation

The 7SR46 can work with an external auxiliary supply during normal service. If that supply is unavailable, the relay can obtain operating energy from the current flowing through its compatible protection CTs.

This arrangement is useful for substations where a station battery, DC supply or dependable auxiliary AC supply is not available. The relay reaches its trip-ready condition at specified current levels: Siemens states 80% of the minimum CT current for a single-phase condition and 40% for a three-phase condition.

The CTs form an important part of the protection system. A standard 1 A or 5 A protection CT should not automatically be assumed suitable. The 7SR46 is designed for specified Class 5P80 CT types, and the CT rating must match the selected relay ordering code.

Features

• Can operate without depending fully on an external auxiliary supply
• Suitable for RMU and compact medium-voltage switchgear panels
• Provides phase overcurrent and derived earth-fault protection
• Definite-time and inverse-time curves support protection coordination
• Dedicated switch-onto-fault function provides fast fault clearance
• Transformer inrush detection can prevent unnecessary protection operation
• Internal pulse output can initiate circuit-breaker tripping
• External protection trip input allows another protection device to operate the trip circuit
• Two settings groups support different network operating conditions
• Front LCD provides access to settings, measurements and trip information
• Programmable LEDs allow clear local fault indication
• Mechanical trip indication remains visible at the panel
• Front USB connection simplifies local commissioning
• Rear RS485 communication supports SCADA integration
• Stores fault and event records for post-trip checks
• The internal battery maintains the clock and provides access to important records when power is unavailable
• Self-monitoring checks the relay, battery and internal operating condition
• Screw and push-in terminal versions suit different panel-building practices

These features make it a practical option for buyers looking for a CT-powered overcurrent relay for RMU panels, a dual-powered earth-fault protection relay or a numerical feeder protection relay for remote substations.

Applications

Siemens Reyrolle 7SR46 CT-Powered Overcurrent Relays are commonly used for:

• Ring main units
• Secondary distribution substations
• Medium-voltage incoming feeders
• Medium-voltage outgoing feeders
• Cable distribution networks
• MV/LV transformer protection
• Distribution transformer backup protection
• Compact switchgear panels
• Remote electrical substations
• Utility distribution networks
• Industrial power-distribution systems
• Renewable-energy feeder panels
• Water and wastewater pumping stations
• Mining and quarry substations
• Oil and gas distribution panels
• Infrastructure and railway power systems
• Replacement of older electromechanical overcurrent relays
• Switchgear retrofit and protection-panel upgrade projects

Siemens identifies RMUs, incomers, feeders, MV/LV transformers, backup protection and replacement of older electromechanical relays among the main applications for the 7SR46.

Selecting the Correct Reyrolle 7SR46 Relay

A 7SR46 relay should not be selected only from the description “CT-powered protection relay.” The relay, protection CTs and circuit-breaker trip arrangement must work together.

For selection or quotation, provide:

• Complete Siemens MLFB or article number
• System voltage
• Feeder or transformer application
• Rated feeder current
• Short-circuit level
• CT manufacturer, type and ratio
• Confirmation of compatible Class 5P80 CTs
• Required protection curves and settings
• Circuit-breaker make and model
• Trip-coil rating
• Auxiliary supply voltage, when available
• RS485 communication requirement
• Screw or push-in terminal preference
• Local or remote mechanical trip indication requirement
• Quantity and destination country

For a replacement enquiry, share a clear photograph of the existing relay label, CT details, panel wiring diagram and circuit-breaker trip-coil information.

Siemens Reyrolle 7SR46 Supplier and Exporter in India

ARP IMPEX is an independent supplier and exporter of Siemens Reyrolle protection relays in India. We supply the Reyrolle 7SR46 for switchgear manufacturers, panel builders, EPC contractors, utilities and industrial maintenance requirements.

Buyers looking for a Siemens Reyrolle 7SR46 supplier in India, a CT-powered overcurrent protection relay exporter, a self-powered relay for ring main units, or a non-directional overcurrent and earth-fault relay for medium-voltage feeders can send the exact Siemens part number and technical specification for quotation.