Siemens 7SJ6425 Protection Relay

Feature & Principle

It belongs to Siemens SIPROTEC 4 7SJ64 series multifunction protection relay. It samples three-phase current and voltage signals, executes directional phase overcurrent, sensitive earth fault, undervoltage, overvoltage and frequency protection. It supports optional synchronizing check for generator or grid interconnection. It is equipped with RTD interface for winding temperature monitoring. Built-in fault recording, event log and breaker control logic. It supports IEC61850 Ethernet and RS485 communication, configured via DIGSI 4 software. This relay is discontinued and widely used as replacement spare for old medium voltage switchgear.

Specifications

Model: 7SJ6425 Brand: Siemens Series: SIPROTEC 4 Core function: Directional overcurrent, earth fault, voltage / frequency protection, optional synchronizing Extra interface: RTD temperature input Communication: IEC61850 Ethernet, RS485 Display: Graphic LCD I/O: Configurable binary inputs and relay outputs Mounting: Flush panel mount Power supply: 110~250VDC / 115~230VAC Application: Medium voltage feeder, generator grid interconnection, large motor protection cabinet Certification: CE, IEC60255

Components & Diagnostics

AC sampling circuit, main CPU, graphic display, Ethernet / RS485 communication chip, relay output matrix, watchdog circuit, status LED. Common faults: communication offline, measurement deviation, false tripping, synchronizing check failure, power supply damage.

Product Brief

7SJ6425 protection relay, Siemens SIPROTEC 4 feeder and synchronizing protection spare widely used for MV switchgear overhaul and replacement.