ABB REF615C｜Feeder Protection and Control｜

Functional Diagram Overview

The functional diagrams of the ABB REF615 IED provide a graphical representation of the device functionality from multiple engineering perspectives, including:

Protection functions
Measurement functions
Condition monitoring
Disturbance recording
Control functions
Interlocking logic

The diagrams illustrate the default REF615 configuration using simplified logical symbols to represent the internal functional relationships and signal paths.

The functional diagrams also show the external connections to primary electrical equipment, including the default wiring arrangements for:

Current transformers (CTs)
Voltage transformers (VTs)
Binary input signals
Binary output signals
Protection Direction Reference

For directional protection functions, the default positive measurement direction is defined as:

Towards the outgoing feeder

This reference direction is used for functions such as:

Directional overcurrent protection
Directional earth-fault protection
Power-related protection functions

Correct directional configuration ensures that fault direction decisions correspond with the actual feeder topology.

Functional Diagram Structure

The REF615 functional diagrams are divided into separate sections.

Each section represents one functional entity, such as:

Protection stage
Measurement function
Control logic
Monitoring function
Recording function
Input/output interface

The external connections are also divided into corresponding sections.

Only the connections relevant to a specific functional entity are displayed in each section, improving readability and simplifying engineering analysis.

Protection Function Block Identification

Protection function blocks are included directly in the functional diagrams.

Each function block is identified using:

IEC 61850 function name
IEC function symbol
ANSI device/function number

Example:

Identification Method Example
IEC 61850 name PHHPTOC
ANSI function number 50/51
IEC symbol Protection function symbol

This naming method allows engineers to easily correlate the functional diagrams with:

IEC 61850 data models
Protection engineering documents
Relay setting tools
ANSI protection standards
Function Block Instance Numbering

Some protection function blocks may be used multiple times within the same REF615 configuration.

For example:

PHHPTOC
(High-stage phase overcurrent protection)

may appear more than once depending on the selected application configuration.

To distinguish multiple instances, the function block identification includes a sequential instance number.

Example:

PHHPTOC1
PHHPTOC2
PHHPTOC3

The numbering starts from:

1 and increases upward

If a function block does not have an appended number, it means:

The function is used only once in the configuration.
Separation Between Internal Logic and External Connections

The functional diagrams clearly separate:

Internal IED Functionality

Includes:

Protection logic
Control logic
Measurement processing
Internal signals
IEC 61850 logical nodes
External Connections

Includes:

CT/VT inputs
Binary inputs
Binary outputs
External control signals

The separation is represented by a:

Dashed line indicating the physical IED enclosure

This distinction helps engineers understand which signals exist:

Inside the relay
Outside the relay wiring interface
Signal Matrix and Application Configuration

The REF615 standard configuration can be modified using ABB’s PCM600 Protection and Control IED Manager engineering tools.

Two main tools are used:

Signal Matrix
Application Configuration
Signal Matrix Tool

The Signal Matrix tool is used primarily for signal mapping and engineering.

These functions:

Cannot be removed
Remain available even if modification is attempted through Application Configuration

Mandatory blocks are retained because they are required for:

Core relay operation
Communication integrity
System management functions
Engineering Workflow Example

A typical REF615 customization process:

Step Engineering Activity Tool
1 Select standard REF615 configuration PCM600
2 Review default functional diagrams Documentation
3 Modify signal routing Signal Matrix
4 Add/remove application functions Application Configuration
5 Configure IEC 61850 communication PCM600
6 Download configuration to IED PCM600
7 Perform commissioning tests Test equipment
Procurement and Maintenance Considerations
Feature Engineering Benefit
IEC 61850-based function identification Simplifies integration with modern substations
Instance numbering Enables clear identification of duplicated protection stages
Functional diagrams Provides complete protection and control documentation
Signal Matrix customization Simplifies I/O and GOOSE mapping
Application Configuration Enables flexible application modification
Automatic data model update Maintains IEC 61850 consistency
Mandatory function protection Prevents removal of critical system functions