Differential Protection - ABB Relion 670 Series Product Manual

Busbar protection REB670
Version 2.2
Table 14. Basic IED functions, continued
IEC 61850 or function Description
name
SAFEFILECOPY Safe file copy function
ALTMS Time master supervision
ALTIM Time management
CAMCONFIG Central account management configuration
CAMSTATUS Central account management status
TOOLINF Tools information
COMSTATUS Protocol diagnostic
Table 15. Local HMI functions
IEC 61850 or function Description
name
LHMICTRL Local HMI signals
LANGUAGE Local human machine language
SCREEN Local HMI Local human machine screen behavior
FNKEYTY1–FNKEYTY5 Parameter setting function for HMI in PCM600
FNKEYMD1–
FNKEYMD5
LEDGEN General LED indication part for LHMI
OPENCLOSE_LED LHMI LEDs for open and close keys
GRP1_LED1– Basic part for CP HW LED indication module
GRP1_LED15
GRP2_LED1–
GRP2_LED15
GRP3_LED1–
GRP3_LED15

4. Differential protection

The function consists of differential protection algorithm,
sensitive differential protection algorithm, check zone
algorithm, open CT algorithm and two supervision
algorithms.
Busbar differential protection
This protection function is intended for fast and selective
tripping of faults within the protected zone. For each current
input, the CT ratio can be set from the local HMI or via the
parameter-setting tool in PCM600. In this way adaptation to
different CT ratios is provided in the simplest way. The
minimum pick-up value for the differential current is then set
to give a suitable sensitivity for all internal faults. This
setting is made directly in primary amperes. For busbar
protection applications typical setting value for the minimum
differential operating current is from 50% to 150% of the
biggest CT.
All current inputs are indirectly provided with a restraint
feature. The operation is based on the well-proven RADSS
28
percentage restraint stabilization principle, with an extra
stabilization feature to stabilize for very heavy CT
saturation. Stability for external faults is guaranteed if a CT
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is not saturated for at least two milliseconds during each
power system cycle. It is also possible to add external
tripping criteria by binary signal.
The trip command from the differential protection including
sensitive differential protection and circuit breaker failure
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backup-trip commands can be set either as self-resetting or
latched. In second case the manual reset is needed in order
to reset the individual bay trip output contacts.
Sensitive differential level
Differential protection zones in REB670 include a sensitive
operational level. This sensitive operational level is
designed to be able to detect internal busbar earth faults in
low impedance earthed power systems (i.e. power systems
where the earth-fault current is limited to a certain level,
typically between 300A and 2000A primary by a neutral
point reactor or resistor). For increased security, the
sensitive differential protection must be externally enabled
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1MRK 505 373-BEN P
SEMOD120950-5 v6
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