ABB Distributed busbar protection REB500

ABB Distributed busbar protection REB500

Main features

• Low-impedance busbar protection

• Stub and T-zone protection

• High functional reliability due to two independent

measurement criteria:

- stabilized differential current algorithm

- directional current comparison algorithm

• Phase-by-phase measurement

• Reduced CT performance requirements

• High through-fault stability even in case of

CT saturation

• Full solid-state busbar replica

• No switching of CT circuits

• Only one hardware version for

- 1 and 5 A rated currents

- all auxiliary supply voltages between 

48 V DC an

Bay unit (500BU03)

The bay unit (see Fig. 4) is the interface

between the protection and the primary system

process comprising the main CTs, isolators

and circuit-breaker and performs the

associated data acquisition, pre-processing,

control functions and bay level protection

functions. It also provides the electrical insulation

between the primary system and the

internal electronics of the protection.

The input transformer module contains four

input CTs for measuring phase and neutral

currents with terminals for 1 A and 5 A. Additional

interposing CTs are not required,

because any differences between the CT

ratios are compensated by appropriately configuring

the software of the respective bay

units.

Optional input transformer module also contains

five input voltage transformers for the

measurement of the three-phase voltages and

two busbar voltages and recording of voltage

disturbances or 6 current transformers for

transformer differential protection. (see 

Fig. 12).

In the analog input and processing module,

the analog current and voltage signals are

converted to numerical signals at a sampling

rate of 48 samples per period and then

numerically preprocessed and filtered accordingly.

Zero-sequence voltage and zero-current

signals are also calculated internally. The Process

d 250 V DC

- nominal frequencies of 50, 60 and 

16.7 Hz

• Short tripping times independent of the

plant’s size or configuration

• Centralized layout: Installation of hardware

in one or several cubicles

• Distributed layout: Bay units distributed

and, in the case of location close to the

feeders, with short connections to CTs, isolators,

circuit breakers, etc.

• Connections between bay units and central

unit by fiber-optic cables

- maximum permissible length 1200 m

- for distributed and centralized layout

• fiber-optic connections mean interferenceproof

data transfer even close to HV power

cables

• Replacement of existing busbar protection

schemes can be accomplished without restrictions

(centralized layout) in the case of

substation extensions e.g. by a mixture of

centralized and distributed layout

• Easily extensible

• User-friendly, PC-based human machine

interface (HMI)

• Fully numerical signal processing

• Comprehensive self-supervision

• Binary logic and timer in the bay unit

• Integrated event recording

• Integrated disturbance recording for power

system currents

• A minimum of spare parts needed due to

standardization and a low number of varying

units

• Communication facilities for substation

monitoring and control systems via 

IEC 61850-8-1, IEC 60870-5-103 and LON

• IEC 62439 standard redundant station bus

communication

• IEC 61850-9-2 LE process bus communication

• Cyber security to support

- User Access Management

- User Activity Logging

Options

• Breaker failure protection (also separately

operable without busbar protection)

• End fault protection

• Definite time overcurrent protection

• Breaker pole discrepancy

• Current and voltage release criteria

• Disturbance recording for power system

voltages

• Separate I0 measurement for impedancegrounded

networks

• Communication with substation monitoring

and control system (IEC 61850-8-1 /

IEC 60870-5-103 / LON)

• Internal user-friendly human machine interface

with display

• Redundant power supply for central units

and/or bay units

REB500

The numerical busbar protection REB500 is

designed for the high-speed, selective protection

of MV, HV and EHV busbar installations

at a nominal frequency of 50, 60 and 16.7 Hz.

The structure of both hardware and software

is modular enabling the protection to be easily

configured to suit the layout of the primary

system.

The flexibility of the system enables all configurations

of busbars from single busbars to

quadruple busbars with transfer buses, ring

busbars and 1½ breaker schemes to be protected.

In 1½ breaker schemes the busbars and the

entire diameters, including Stub/T-Zone can

be protected. An integrated tripping scheme

allows to save external logics as well as wiring.

The capacity is sufficient for up to 60 feeders

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

The numerical busbar protection REB500

detects all phase and earth faults in solidly

grounded and resistive-grounded power systems

and phase faults in ungrounded systems

and systems with Petersen coils.

The main CTs supplying the currents to the

busbar protection have to fulfil only modest

performance requirements (see page 18). The

protection operates discriminatively for all

faults inside the zone of protection and

remains reliably stable for all faults outside the

zone of protection.

REB500sys

The REB500sys is foreseen in MV, HV and

EHV substations with nominal frequencies of