ABB Distributed busbar protection REB500

16.7, 50 Hz or 60 Hz to protect the busbars

and their feeders. The bay protection functions

included in REB500sys are used as

Main 2 / Group 1 - or back-up protection.

The system REB500sys is foreseen for all single

or double busbar configurations (Line variants

L-V1 to L-V7 and Transformer variant TV1

to T-V4). In 1½ breaker configurations,

variant L-V5 can be used for the bay level

functions autoreclosure and synchrocheck.

The capacity is sufficient for up to 60 feeders

(bay units) and a total of 32 busbar zones.

The REB500sys detects all bus faults in solidly

and low resistive-grounded power systems,

all kind of phase faults in ungrounded

and compensated power systems as well as

feeder faults in solidly, low resistive-grounded,

compensated and ungrounded power systems.

The protection operates selectively for all

faults inside the zone of protection and

remains reliably stable for all faults outside the

zone of protection.

REB500sys is perfectly suited for retrofit concepts

and stepwise upgrades. The bay unit is

used as a stand-alone unit for bay protection

functions (e.g. line protection, autoreclosure

and synchrocheck or 2- and 3 winding transformer

protection or autonomous T-zone protection).

The central unit can be added at a

later stage for full busbar and breaker failure

protection functionality.

data are transferred at regular intervals

from the bay units to the central processing

unit via the process bus.

Every bay unit has 20 binary inputs and 16

relay outputs. The binary I/O module detects

and processes the positions of isolators and

couplers, blocking signals, starting signals,

external resetting signals, etc. The binary

input channels operate according to a patented

pulse modulation principle in a nominal

range of 48 to 250 V DC. The PC-based HMI

program provides settings for the threshold

voltage of the binary inputs. All the binary output

channels are equipped with fast operating

relays and can be used for either signaling or

tripping purposes (see contact data in Table

8).

A software logic enables the input and output

channels to be assigned to the various functions.

A time stamp is attached to all the data

such as currents, voltages, binary inputs,

events and diagnostic information acquired by

a bay unit.

Where more binary and analog inputs are

needed, several bay units can be combined to

form a feeder/bus coupler bay (e.g. a bus coupler

bay with CTs on both sides of the bus-tie

breaker requires two bay units).

The bay unit is provided with local intelligence

and performs local protection (e.g. breaker

failure, end fault, breaker pole discrepancy),

bay protection (Main 2 or back-up bay protections)

as well as the event and disturbance

recording.

High-speed distance protection

• Overcurrent or underimpedance starters

with polygonal characteristic

• Five distance zones (polygon for forwards

and reverse measurement)

• Load-compensated measurement

• Definite time overcurrent back-up protection

(short-zone protection)

• System logic

- switch-onto-fault

- overreach zone

• Voltage transformer circuit supervision

• Power swing blocking function

• HF teleprotection. The carrier-aided

schemes include:

- permissive underreaching transfer tripping

- permissive overreaching transfer tripping

- blocking scheme with echo and transient

blocking functions

• Load-compensated measurement

- fixed reactance slope

- reactance slope dependent on load

value and direction (ZHV<)

• Parallel line compensation

• Phase-selective tripping for single and

three-pole autoreclosure

• Four independent, user-selectable setting

groups.

In the supervision mode the active and reactive

power with the respective energy direction

is displayed by the HMI500.

Autoreclosure

The autoreclosure function permits up to four

three-phase autoreclosure cycles. The first

cycle can be single phase or three-phase.

If the REB500sys autoreclosure function is

employed, it can be used as a back-up for the

autoreclosure realized externally (separate

equipment or in the Main 1 protection).

When the autoreclosure function is realized

outside of REB500sys, all input and output

signals required by the external autoreclosure

equipment are available in order to guarantee

correct functionality.

Synchrocheck

The synchrocheck function determines the difference

between the amplitudes, phase

angles and frequencies of two voltage vectors.

The synchrocheck function also contains

checks for dead line and dead bus.

Transformer differential protection

• For two- and three-winding transformers

• Auto transformers

• Three-phase function

• Current-adaptive characteristic

• High stability for external faults and current

transformer saturation

• No auxiliary transformers necessary

because of vector group and CT ratio compensation

• Inrush restraint using 2nd harmonic

The transformer differential protection function

can also be used as an autonomous T-zone

protection in a 1½ breaker scheme.

Thermal overload

This function protects the insulation against

thermal stress. This protection function is normally

equipped with two independently set

levels and is used when oil overtemperature

detectors are not installed.

Peak value over- and undercurrent protection

These functions are used for current monitoring

with instantaneous response and where