1½ Breaker Schemes And Duplex Stations - ABB RELION REB500 Applications Manual
Distributed busbar protection, version 8.3 iec
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Also See for RELION REB500:
- Technical manual (194 pages) ,
- Operation manual (110 pages) ,
- Engineering manual (98 pages)
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1MRK 505 399-UEN B
Section 12
This section describes the application of the busbar, breaker failure and end fault protection
functions in 1½ breaker schemes and duplex stations. The description is based on typical
station layouts.
1½ breaker schemes can be divided into five main groups (versions 1 to 5) which have to be
considered separately from the point of view of discrimination, along with one version for the
application of REB500 to duplex stations:
1.
1½ breaker scheme with 3 CTs per diameter
2.
1½ breaker scheme with 6 CTs per diameter
3.
1½ breaker scheme with 5 CTs per diameter
4.
1½ breaker scheme with 8 CTs per diameter
5.
1½ breaker scheme with BBP only
6.
Duplex stations
Table 7 lists the characteristics of these 6 versions (* indicates that the characteristic is not
relevant to REB500).
Table 7:
Characteristic
Number of CTs
Number of REB500 BUs
Number of REB500 BFP functions
Number of REB500 EFP functions
Number of T-zones protected by REB500
Number of Bay protection devices (LP, TP)
Incidence
One advantage of REB500 in the case of a 1½ breaker scheme is that the so-called T-zone is
fully protected.
The T-zone is the section of busbar between the CTs plus the line T up to the open line isolator.
The bay protection (distance protection) does not detect faults in this zone correctly, because
the voltage measured is the wrong one (open line isolator).
This zone is normally protected by an overcurrent function included in the line protection. This
reacts, however, to CT saturation during through-faults (for example, busbar faults) and could
mal-operate.
REB500 uses its current restrained differential protection and phase comparison functions to
protect this zone. The corresponding algorithm operates discriminately even if CTs saturate.
Busbar protection systems are generally used to discriminatively protect main busbars. In
addition to this, however, REB500 is also able to effectively protect the T-zone of a 1½ breaker
scheme, because it creates an image of the topology of the entire station with up to 32
independent protection zones, each processed by the busbar protection algorithms (current
restrained differential and phase comparison protection).
Distributed busbar protection REB500
Application manual
1½ breaker schemes and duplex
stations
1 ½ breaker scheme groups and duplex stations
© Copyright 2019 ABB. All rights reserved
1½ breaker schemes and duplex stations
1
2
3
4
3
6
5
8
3
3
5
8
3
3
3
3
3
0
3
0
1
1
2
2
2
2
2
2
high
high
mid
low
Section 12
GUID-BF46C130-5296-436A-B06E-814B5B587E84 v2
5
6
*
2
2
2
0
2
0
2
0
2
*
2
mid
low
87
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