Description
The ABB REL551 1MRK002480-AE is a numerical line protection terminal from ABB’s 500-series protection platform. It was designed for protection, control, and monitoring of overhead lines and cables in distribution, subtransmission, and transmission applications. The REL551 supports selective fault detection and can provide one-, two-, or three-pole tripping depending on the configured application.
The relay combines protection functions with measurement, event recording, self-supervision, and local HMI functions. It is particularly associated with line protection applications where dependable fault detection and selective circuit-breaker operation are required.
🔧 Key Features
• ABB REL551 line protection terminal
• Part number 1MRK002480-AE
• Numerical protection technology
• Line distance protection
• Overcurrent and earth-fault protection
• Automatic reclosing with synchronism check
• One-, two-, and three-pole tripping capability
• Numerical measurement and filtering
• Local front-panel HMI
• Event and fault recording
• Extensive self-supervision and diagnostics
• Modular hardware architecture
📋 Product Datasheet
• Brand: ABB
• Model: REL551
• Order Number: 1MRK002480-AE
• Product Type: Line Protection Terminal / Numerical Relay
• Series: ABB 500-Series
• Main Application: Overhead Line and Cable Protection
• Protection Functions: Distance, Overcurrent, Earth Fault, Auto-Reclosing
• Tripping: 1-pole / 2-pole / 3-pole, configuration dependent
• Measurement: Numerical current and voltage measurement
• HMI: Local front-panel HMI
• Self-Supervision: Integrated fault diagnostics
• Communication: Configuration dependent; 500-series interfaces include SPA and IEC 60870-5-103 options
• Mounting: Panel / rack installation, configuration dependent
• Power Supply: Auxiliary supply, dependent on ordered hardware
• Operating Temperature: Variant dependent
• Dimensions: Approximately 144 × 144 × 200 mm*
• Weight: Approximately 1.5 kg*
• Country of Origin: ABB manufacturing location dependent
⚙️ Functional Description
The REL551 is intended to detect faults on protected transmission or distribution lines and initiate selective tripping. Its protection platform uses numerical filtering and measurement techniques to maintain correct operation during transient conditions. The relay can be configured for different network arrangements and protection requirements.
Distance protection can be used to determine the electrical location of faults along a protected line, while overcurrent and earth-fault elements provide additional protection functions. Automatic reclosing and synchronism-check functions can be included where required by the application.
🏭 Typical Applications
• Transmission line protection
• Subtransmission networks
• Distribution substations
• Overhead power-line protection
• Underground cable protection
• Series-compensated network applications
• Utility protection systems
• Industrial power networks
🔌 Installation & Configuration
Basic replacement procedure:
• Verify the complete part number 1MRK002480-AE
• Check the relay hardware configuration
• Confirm CT and VT wiring
• Compare terminal assignments with the existing relay
• Install the relay in the designated panel or rack position
• Connect auxiliary power and protection wiring
• Restore the saved protection settings
• Verify communication parameters
• Perform secondary injection testing before returning the circuit to service
🛠️ Commissioning Checklist
• Check auxiliary power
• Verify relay self-supervision status
• Confirm CT/VT measurements
• Verify protection settings
• Test overcurrent elements
• Test earth-fault elements
• Test distance protection where applicable
• Verify trip outputs
• Test breaker interface
• Check event and fault records
• Verify station communication
⚠️ Replacement Note
The exact functionality of a REL551 depends on its hardware configuration and ordered options. Some online listings incorrectly describe the same part number as a generic motor or feeder protection relay. ABB documentation and product references identify the REL551 primarily as a line protection terminal, so the existing relay configuration should be checked before selecting a replacement.
📦 Ordering Information
ABB REL551 | 1MRK002480-AE | Line Protection Terminal | Numerical Protection Relay | ABB 500-Series
