ABB REL561 1MRK002496-AC｜Line differential protection terminal｜

Software Toolbox

A powerful engineering software environment provides tools for:

Monitoring
Disturbance evaluation
Parameter configuration
Logic customization
Protection analysis

Functions include:

Online monitoring
Signal tracing
Event analysis
Setting management
Main Application Purpose

The primary purpose of the REL 551 terminal is:

Protection, control, and monitoring of overhead lines and cables.

It supports:

Single-pole tripping
Two-pole tripping
Three-pole tripping

depending on system requirements and protection philosophy.

True Current Differential Protection Advantages

The REL 561’s true current differential protection provides:

Excellent sensitivity
Accurate phase selection
Fast fault clearance
High selectivity

It is particularly suitable for:

Complex network configurations
High reliability transmission systems
Critical cable and overhead line applications
REL 551 Functional Summary
Category Function
Primary Application Overhead line and cable protection
Main Protection Phase-segregated line differential protection
Backup Protection Phase and residual overcurrent protection
Equipment Protection Thermal overload protection
Fault Analysis 10 disturbance records, 40-second recorder
Control Breaker/disconnector control functions
Indication 18 programmable LEDs
Communication Dual serial protocols
Time Accuracy 1 ms synchronization resolution
Configuration Four independent setting groups
Engineering Tool Monitoring, analysis, and configuration software