Siemens 7SJ64 SIPROTEC Feeder Protection Relay Unit

Module Feature

7SJ6451-5EB92-1HG4 belongs to Siemens SIPROTEC 7SJ64 series digital protection relay for feeder application.

It integrates multiple protection functions including phase overcurrent, earth fault, sensitive earth fault, thermal overload, breaker failure and voltage supervision. It supports flexible protection curve setting such as IEC and ANSI inverse time curves. Built-in disturbance recorder for fault waveform storage, supports local HMI operation and remote communication. Communication interfaces support PROFIBUS DP, Modbus and IEC60870-5-103. It is suitable for medium voltage feeder, large motor and small generator protection in industrial plant and power grid substation.

Working principle

CT and VT signals are sampled and converted to digital values inside the relay.

Protection algorithms continuously calculate current, voltage and sequence components. When measured value exceeds protection setting threshold, the relay triggers trip output to open circuit breaker, meanwhile records fault event and COMTRADE waveform. It transmits real-time measurement, alarm and fault data to SCADA system via fieldbus.

Onboard components

Signal conditioning board, AD sampling chip, main CPU processor, DI/DO output circuit, communication transceiver module, LCD HMI panel, status LED array, rear terminal block assembly and power supply unit.

LED indicators

Front LEDs indicate power healthy, RUN status, SF system fault, trip action and bus communication active.

Hardware self‑diagnosis

Built-in supervision monitors supply voltage, CT/VT wire break, internal memory error, communication timeout and hardware anomaly. Fault codes and disturbance files can be read by DIGSI 4 software.

Programming software

DIGSI 4, used for protection setting, communication parameter configuration, disturbance record download and relay calibration.

Electrical & Process Parameters

Model:7SJ6451-5EB92-1HG4 Brand:Siemens Device type:Multifunction numerical feeder protection relay Function:Overcurrent, earth fault, overload interlock and electrical measurement for medium voltage feeder

Mechanical & Structure

Mounting:Standard 19-inch panel flush mounting Protection class:IP40 front panel, IP20 rear side Housing:Reinforced metal industrial relay housing

Environmental

Operating temperature:-20℃ ~ +60℃ Storage temperature:-40℃ ~ +85℃ Ambient humidity:5~95% non‑condensing

Certification:CE, IEC 60255, UL

Status:Original Siemens SIPROTEC protection spare

Installation

Check CT polarity and wiring before power on.

Download protection setting file, set communication address and perform protection injection test before commissioning.

Interface

CT/VT analog input terminal, DI/DO binary input output terminal, PROFIBUS-DP port, service RS232 port, DC auxiliary power terminal.

Diagnostic

SF fault light: Hardware error, configuration mismatch or power supply abnormality. No trip command: Protection blocking active, setting value mismatch or output contact damage. Communication interruption: Bus cable fault, station address conflict or communication module failure.

Product Brief

Siemens 7SJ6451-5EB92-1HG4 protection relay, SIPROTEC 7SJ64 multifunction feeder protection spare for substation medium voltage protection cabinet replacement.