The ABB RED615 is a phase-segregated, two-end line differential protection and control Intelligent Electronic Device (IED) designed for utility and industrial power distribution systems. As a member of ABB’s Relion® 615 Series, the RED615 provides high-speed, unit-type protection for overhead lines and cable feeders while integrating advanced control, monitoring, and communication capabilities.

Engineered in accordance with the IEC 61850 standard, the RED615 supports seamless interoperability within modern digital substations and is particularly well suited for looped and meshed distribution networks, including systems with distributed or decentralized power generation.

Key Features
Phase-segregated two-end line differential protection
High-speed unit-type protection for overhead lines and cable feeders
Integrated feeder control and monitoring
Backup overcurrent protection
Earth fault protection (Standard Configurations B and C)
Support for looped and meshed distribution networks
Compatible with distributed generation applications
IEC 61850 Edition-compliant communication
GOOSE messaging for peer-to-peer communication
Flexible engineering with application-specific settings
Primary Protection

The RED615 provides unit-type line differential protection, which compares current measurements from both ends of the protected feeder to detect internal faults with high speed and selectivity.

The protection zone is precisely defined by the current transformers (CTs) installed at the local and remote substations, ensuring that only faults within the protected feeder section initiate a trip command.

Key benefits include:

Instantaneous fault detection
High sensitivity to internal faults
Excellent stability during external faults
Absolute selectivity without coordination delays
Reliable protection for both overhead lines and underground cable feeders
Backup Protection Functions

In addition to line differential protection, the RED615 incorporates current-based backup protection to improve overall system reliability.

Available backup functions include:

Phase overcurrent protection for remote backup of downstream protection IEDs
Local backup protection for the line differential function
Earth fault protection (available in Standard Configurations B and C)

These integrated functions provide dependable fault clearing even if downstream protection devices or communication channels are unavailable.

Network Compatibility

The RED615 is designed for operation in a wide range of distribution network grounding systems, including:

Isolated neutral systems
Resistance-grounded systems
Compensated (impedance-grounded) systems
Solidly grounded systems

After application-specific parameters are configured, the IED can be placed directly into service without additional customization.

Communication and Substation Automation

The RED615 fully supports modern substation automation through multiple industry-standard communication protocols, including:

IEC 61850 with high-speed GOOSE messaging
IEC 60870-5-103
Modbus®
DNP3

These communication capabilities enable seamless integration with SCADA systems, protection relays, remote terminal units (RTUs), and digital substation architectures.

Advanced Inter-Substation Communication

The RED615 extends traditional line differential protection by combining:

Horizontal GOOSE communication over the station bus
Binary signal transfer over the protection communication link

This architecture enables advanced protection and automation schemes that go beyond conventional differential protection.

Loss-of-Mains (LOM) Protection

One notable application is Loss-of-Mains (LOM) protection in networks containing distributed generation.

By combining high-speed binary signal transfer with GOOSE messaging, the RED615 provides:

Faster fault detection
Improved selectivity
Greater operational reliability

Compared with conventional LOM protection methods, this integrated communication approach delivers superior performance for distributed energy applications.

Ideal Solution for Closed-Loop Distribution Networks

The RED615 is particularly effective in closed-loop and meshed distribution networks, where maintaining power availability is a primary operational objective.

Under normal operating conditions, feeder loops remain closed to ensure continuous power supply to end users. In these configurations, faults are typically supplied with fault current from both directions, making selective protection difficult when using conventional overcurrent relays.

Traditional directional and non-directional overcurrent protection often require complex coordination and may not provide sufficiently fast or selective fault isolation.

Recommended other models：