Category: ABB

Power transformer differential protection

The relay offers low-impedance differential protection for two

winding (two restraints) and three-winding (three restraints)

power transformers. The power transformer protection

application package includes the protection for a two-winding

power transformer. If support for three-winding power

transformer is needed, the corresponding protection add-on

package can be selected. Both low-impedance differential

functions feature three-phase multi-slope stabilized stages and

an instantaneous stage to provide fast and selective protection

against short circuits, winding interturn faults and bushing

flash-overs. A second harmonic restraint with advanced

waveform-based blocking ensures stability at transformer

energization. The fifth harmonic based blocking and unblocking

limits stabilize the protection performance in moderate

overexcitation situations. In case of three-winding differential

protection, the connection group phase shift matching can be

done with 0.1 degree resolution supporting cycloconverter

applications. If the tap-changer position information is

available, it is possible to further increase the protection

sensitivity by compensating the tap-changer position error

within the measured differential current.

The power transformer protection application package also

includes high-impedance differential functions for a phase

segregated protection scheme. If this scheme is applied, the

related current transformers have to be correctly selected and

the necessary secondary circuit components, external to the

relay, defined.

Arc flash protection

The arc flash protection is available on the optional hardware

module. The module supports connection of up to four sensors.

The sensors can be of lens or loop types, or a free mixture. Both

sensor types are supervised against sensor failure. Fast tripping

increases staff safety and limits material damage, therefore it is

recommended to use static power outputs (SPO) instead of

normal power outputs (PO). This typically decreases the total

operating time with 4..6 ms compared to the normal power

outputs.

Measurements

The base functionality of the REX640 relay contains a number of

basic measurement functions for current, voltage, frequency,

symmetrical components of currents and voltages, power,

power factor and energy. These measurement functions can be

freely connected to the measured secondary quantities

available in the relay. The relay can also measure various analog

signals via RTD and mA inputs. All these measurements can be

used within the relay configuration for additional logics. The

measurements are available locally on the HMI and can be

accessed remotely via communication. The information is also

accessible via Web HMI.

The relay is also provided with a load profile recorder. The load

profile feature stores the selected load measurement data

captured periodically (demand interval). The records can be

viewed on the LHMI and are available in COMTRADE format.

The LHMI includes the necessary command, indication and

measurement features for each of the modes, thus rendering

the conventional dedicated synchronizing panel unnecessary.

REX640 also supports systems in which non-generator circuit

breakers are synchronized. The prerequisite is that all the

feeders within the system are equipped with REX640 relays.

The generator relays have to contain the ASGCSYN function

block and all the non-generator relays need to contain the

ASNSCSYN function block. In addition, all the REX640 relays

have to contain the coordinator function block ASCGAPC. The

role of ASCGAPC is to model the system primary circuit

connection state to involve the correct generators for the

synchronization of a non-generator breaker and to interact

between the ASGCSYN and ASNSCSYN function blocks. The

information exchange between ASCGAPC, ASGCSYN and

ASNSCSYN is carried out via binary and analog GOOSE

signalling as per IEC 61850-8-1. The LHMI dedicated to the

relay (breaker) works as the local user interface for a non

generator breaker synchronizing. The available synchronizing

modes are “automatic” and “semi-automatic”. A manual

synchronization of the non-generator breaker can be carried

out as a back-up solution in situations where the

communication system (IEC 61850-8-1) is not available. This

requires operator actions from two LHMIs, namely from the

LHMI of the concerned non-generator breaker and the LHMI of

the manually selected generator relay.

REX640 includes two autoreclosing functions, each with up to

five programmable autoreclosing shots of desired type and

duration. A load-shedding function performs load shedding

based on underfrequency and the rate of change of the

frequency.

To validate correct closing conditions for a circuit breaker,

REX640 contains a synchrocheck function. For installations

including synchronous generators, REX640 introduces a

synchronizer that actively controls the generator’s voltage and

frequency in order to reach a synchronous situation across the

circuit breaker. The synchronizer functionality is available for a

generator circuit breaker as well as for a non-generator

(network) circuit breaker. A complete installation-wide

synchronizing system can be built using the REX640 relays. The

maximum size of the synchronizing system is eight generator

breakers and 17 non-generator breakers.

Synchronization of a generator circuit breaker can be

implemented using a single REX640 relay including the

ASGCSYN function block. The relay interfaces the external

measurement and control circuitry via hardwired binary and

analog signals. The excitation and prime mover control signals

are based on pulse commands, either with fixed or variable

length. The synchronizer function block has three different

function modes: manual, semi-automatic and automatic. In

each of these modes, the LHMI acts as the local user interface.

The LHMI includes the necessary command, indication and

measurement features for each of the modes, thus rendering

the conventional dedicated synchronizing panel unnecessary.

REX640 also supports systems in which non-generator circuit

breakers are synchronized. The prerequisite is that all the

feeders within the system are equipped with REX640 relays.

Control

REX640 integrates functionality for controlling objects such as

circuit breakers, disconnectors, earthing switches, on-load tap

changers and Petersen coils via the LHMI or by means of

remote controls. The relay includes three circuit breaker control

blocks. In addition, the relay features 14 disconnector control

blocks intended for the motor-operated control of

disconnectors or a circuit breaker truck and three control

blocks intended for the motor-operated control of the earthing

switch. Furthermore, the relay includes eight additional

disconnector position indication blocks and three earthing

switch position indication blocks that can be used with

disconnectors and earthing switches that are only manually

controlled.

The touch screen LHMI supports a single-line diagram with

control points and position indication for the relevant primary

devices. Interlocking schemes required by the application are

configured using Signal Matrix or Application Configuration in

PCM600.

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.

The GOOSE Analyzer interface in COM600S enables the

monitoring and the analysis of the horizontal IEC 61850

application during commissioning and operation at station

level. It logs all GOOSE events during substation operation to

enable improved system supervision.

Supported ABB solutions

The REX640 protection relay together with the Substation

Management Unit COM600S constitutes 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, including single-line diagram

templates 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.

REX640 offers native support for IEC 61850 Edition 2 including

binary and analog horizontal GOOSE messaging. In addition, a

process bus enabling sending and receiving of sampled values

of analog currents and voltages is supported.

Unlike the traditional hardwired, inter-device signaling, peer-to

peer communication over a switched Ethernet LAN offers an

advanced and versatile platform for power system protection.

Among the distinctive features of the protection system

approach, enabled by the full implementation of the IEC 61850

substation automation standard, are fast communication

capability, continuous supervision of the protection and

communication system’s integrity, and flexible reconfiguration

and upgrades. This protection relay series is able to optimally

use the interoperability provided by the IEC 61850 Edition 2

features.

The LHMI presents pages in two categories: the Operator

pages and the Engineer pages. The Operator pages include the

ones which are typically required as a part of an operator’s

normal activities, such as a single-line diagram, controls,

measurements, events, alarms, and so on. The Engineer’s

pages include specifically designed pages supporting relay

parametrization, troubleshooting, testing and commissioning

activities.

The Operator pages can be used as such or customized

according to the project’s requirements using Graphical Display

Editor (GDE) within the PCM600 software tool. The Engineer

pages are fixed and cannot be customized.

The Operator pages can be scrolled either by tapping the Home

button or by swiping the actual pages. The Engineer pages are

accessible by touching the upper horizontal section of the

screen.

The LHMI is an accessory for the relay which is fully operational

even without the LHMI. The relay communication card has a

dedicated port where the LHMI is connected using an RJ-45

connector and a CAT6 S/FTP cable. The LHMI can be

connected to the relay also via station communication network

if a longer distance is required between the relay and the LHMI.

Additionally, the LHMI contains one Ethernet service port with

an RJ-45 connector and one USB port. The service port can be

used for the PCM600 connection or for Web HMI connection.

Data transfer to a USB memory is enabled via the USB port. By

default the USB port is disabled and has to be taken into use

with a specific parameter.

Local HMI

The LHMI uses rugged 7-inch high resolution color screen with

capacitive touch sensing technology. The user interface has

been carefully designed to offer the best situational awareness

to the user. Visualization of the primary process measurements,

events, alarms and switching objects’ statuses makes the local

interaction with the relay extremely easy and self-evident. The

LHMI provides a control point for the selected primary devices

via pop-up operator dialogs.

Additionally, the LHMI supports the engineer during the relay’s

testing, commissioning and troubleshooting activities. The

information, traditionally accessible through different paths

within the menu structure, is provided in collectively grouped

and visualized format.

The Home button at the bottom of the LHMI indicates the

relay’s status at a glance. In normal situations, the Home button

shows a steady green light. Any other situation that requires the

operator’s attention is indicated with a flashing light, a red light

or a combination of these.

Description

REX640 is a powerful all-in-one protection and control relay for

use in advanced power distribution and generation applications

with unmatched flexibility available during the complete life

cycle of the device – from ordering of the device, through

testing and commissioning to upgrading the functionality of the

modular software and hardware as application requirements change.

The modular design of both hardware and software elements

facilitates the coverage of any comprehensive protection

application requirement that may arise during the complete life

cycle of the relay and substation.

REX640 makes modification and upgrading easy and pushes

the limits of what can be achieved with a single device.

Application packages

REX640 offers comprehensive base functionality. However, it is

possible to further adapt the product to meet special installation

needs by including any number of the available optional

application packages into a single REX640 relay. For the

selected application packages, the functionality can be

extended by including the related add-on package. The

REX640 connectivity package guides the engineer in optimizing

the application configuration and its performance.

Local HMI

The LHMI uses rugged 7-inch high resolution color screen with

capacitive touch sensing technology. The user interface has

been carefully designed to offer the best situational awareness

to the user. Visualization of the primary process measurements,

events, alarms and switching objects’ statuses makes the local

interaction with the relay extremely easy and self-evident. The

LHMI provides a control point for the selected primary devices

via pop-up operator dialogs.