Month: January 2026

Access control

To protect the relay from unauthorized access and to maintain

information integrity, the relay is provided with a four-level, role

based authentication system with administrator-programmable

individual passwords for the viewer, operator, engineer and

administrator levels. The access control applies to the local

HMI, the Web HMI and PCM600.

Inputs and outputs

The relay is equipped with three phase-segregated differential

current inputs and one residual current input. The differential

and the residual current inputs are rated 1/5 A, that is, the

inputs can be connected to either 1 A or 5 A secondary current

transformers. The optional residual current input rated 0.2/1 A

is normally used in applications requiring sensitive earth-fault

protection and featuring core-balance current transformers.

The rated currents of the analog inputs can be selected in the

relay software. In addition, the binary input threshold (16…176

V DC) can be selected by adjusting the relay’s parameter settings.

All binary input and output contacts are preconfigured

according to the configuration, but can be easily reconfigured

by setting application-based parameters using the signal

configuration functionality of the local HMI and Web HMI.

See the input and output overview table and the terminal

diagram for more information about the inputs and outputs.

Trip circuit supervision

The trip circuit supervision continuously monitors the availability

and operation of the trip circuit. It provides two open-circuit

monitoring functions that can be used to monitor the circuit

breaker’s control signal circuits. It also detects loss of circuit

breaker control voltage.

Self-supervision

The relay’s built-in self-supervision system continuously

monitors the state of the relay hardware and the operation of

the relay software. Any fault or malfunction detected is used for

alerting the operator.

A permanent relay fault blocks the protection functions to

prevent incorrect operation.

Recorded data

The relay has the capacity to store the records of the 128 latest

fault events. The records can be used to analyze the power

system events. Each record includes, for example, current,

residual voltage and angle values, start times of the protection

blocks and a time stamp. The fault recording can be triggered

by the start or the trip signal of a protection block, or by both.

The available measurement modes include DFT, RMS and

peak-to-peak. Fault records store relay measurement values at

the moment when any protection function starts. In addition,

the maximum demand current with time stamp is separately

recorded. The records are stored in the nonvolatile memory.

Trip circuit supervision

The trip circuit supervision continuously monitors the availability

and operation of the trip circuit. It provides two open-circuit

monitoring functions that can be used to monitor the circuit

breaker’s control signal circuits. It also detects loss of circuit

breaker control voltage.

Event log

To collect sequence-of-events information, the relay has a

nonvolatile memory capable of storing 1024 events with the

associated time stamps. The nonvolatile memory retains its

data even if the relay temporarily loses its auxiliary supply. The

event log facilitates detailed pre- and post-fault analyses of

feeder faults and disturbances. The considerable capacity to

process and store data and events in the relay facilitates

meeting the growing information demand of future network

configurations.

The sequence-of-events information can be accessed either via

local HMI or remotely via the communication interface of the

relay. The information can also be accessed locally or remotely

using the Web HMI.

Disturbance recorder

The relay is provided with a disturbance recorder featuring

preconfigured analog and binary channels.The analog channels

can be set to record either the waveform or the trend of the

currents and voltages measured.

The analog channels can be set to trigger the recording function

when the measured value falls below or exceeds the set values.

The binary signal channels can be set to start a recording either

on the rising or the falling edge of the binary signal or on both.

By default, the binary channels are set to record external or

internal relay signals, for example, the start or trip signals of the

relay stages, or external blocking or control signals. Binary relay

signals, such as protection start and trip signals, or an external

relay control signal via a binary input, can be set to trigger the

recording. Recorded information is stored in a nonvolatile

memory and can be uploaded for subsequent fault analysis.

Control

The relay offers control of one circuit breaker or contactor with

dedicated push buttons for opening and closing via the local

HMI or a remote system, for example, PCM600.

By default, the relay is equipped with a single input interlocking

scheme. Binary GOOSE messaging can be used in the creation

of additional interlocking schemes, such as secured object

control (SOC), blocking-based protection schemes or external tripping.

These additional protection and control schemes required by

specific applications are configured using the local HMI, the

Web HMI and the optional application functionality of PCM600.

The local HMI and the Web HMI can be utilized for signal

configuration, while PCM600 is required for the configuration of

GOOSE messaging.

Measurement

The relay continuously measures high-impedance and neutral currents.

The measured values can be accessed via the local HMI or

remotely via the communication interface of the relay. The

values can also be accessed locally or remotely using the Web HMI.

At substation level, COM600S uses the data content of the bay

level devices to enhance substation level functionality.

COM600S features a Web browser-based HMI, which provides

a customizable graphical display for visualizing single-line

mimic diagrams for switchgear bay solutions. The Web HMI of

COM600S also provides an overview of the whole substation,

including relay-specific single-line diagrams, which makes

information easily accessible. Substation devices and

processes can also be remotely accessed through the Web

HMI, which improves personnel safety.

In addition, COM600S can be used as a local data warehouse

for the substation’s technical documentation and for the

network data collected by the devices. The collected network

data facilitates extensive reporting and analyzing of network

fault situations by using the data historian and event handling

features of COM600S. The historical data can be used for

accurate monitoring of process and equipment performance,

using calculations based on both real-time and historical

values. A better understanding of the process dynamics is

achieved by combining time-based process measurements

with production and maintenance events.

COM600S can also function as a gateway and provide

seamless connectivity between the substation devices and

network-level control and management systems, such as

MicroSCADA Pro and System 800xA.

Supported ABB solutions

The 611 series protection relays together with the Substation

Management Unit COM600S constitute a genuine IEC 61850

solution for reliable power distribution in utility and industrial

power systems. To facilitate the system engineering, ABB’s

relays are supplied with connectivity packages. The

connectivity packages include a compilation of software and

relay-specific information and a full relay data model. The data

model includes event and parameter lists. With the connectivity

packages, the relays can be readily configured using PCM600

and integrated with COM600S or the network control and

management system MicroSCADA Pro.

The 611 series relays offer native support for the IEC 61850

standard, including limited binary GOOSE messaging.

Compared to traditional hard-wired, inter-device signaling,

peer-to-peer communication over a switched Ethernet LAN

offers an advanced and versatile platform for power system

protection. The implementation of the IEC 61850 substation

automation standard enables access to distinctive features

including fast software-based communication, continuous

supervision of the protection and communication system’s

integrity, and inherent flexibility for reconfiguration and upgrades.

Application

The high-impedance principle for busbar differential protection

provides a secure and dependable protection scheme against

faults within the measured zone. The high-impedance principle

has been used for many years for differential protection due to

the capability to manage through-faults also with heavy current

transformer (CT) saturation.

The relay’s high-impedance protection functions contain a

built-in blocking functionality, which is provided by the bus-wire

supervision functions to restrict faulty operations in case of

faults in the measurement circuits.

Additional standby (residual) earth-fault protection is provided

by the two non-directional earth-fault stages. The standby

earth-fault protection can be used together with the high

impedance protection functionality to protect motors,

generators and transformers against residual earth faults. The

measurements are taken from the earthing point of the protected object.

The residual earth-fault protection can also be used as bus-wire

supervision especially in new or retrofitting applications where

an earth-fault protection function is used for grounding the

measurement circuits where a short circuit or a break has

occurred. The grounding can be done by an external relay.

Protection functions

REB611 offers phase-segregated (three phases) high

impedance differential protection and non-directional earth

fault protection for busbars, motors and generators. The relay

also offers high-impedance differential-based restricted earth

fault protection for motors, generators, reactors and power

transformers. REB611 is ideally suited for backup protection.

Application

REB611 offers bus-differential protection in a single zone with

bus-wire supervision. It also offers the possibility for bus

differential protection over two zones using two REB611 relays.

The combined restricted earth-fault and residual earth-fault

protection functionalities of the relay enable its use in the

protection of a motor or generator. Due to the individuality of

the high-impedance protection functions, a single relay can be

used for restricted earth-fault protection of both the high and

low voltage sides of a power transformer.