ABB Relion 650 Series Applications Manual page 112

Section 9
Secondary system supervision
9.1.3 Setting guidelines
9.1.3.1 General
The negative and zero sequence voltages and currents always exist due to different non-
symmetries in the primary system and differences in the current and voltage instrument
transformers. The minimum value for the operation of the current and voltage measuring
elements must always be set with a safety margin of 10 to 20%, depending on the system
operating conditions.
Pay special attention to the dissymmetry of the measuring quantities when the function is used on
longer untransposed lines, on multicircuit lines and so on.
The settings of negative sequence, zero sequence and delta algorithm are in percent of the base
voltage and base current for the function,
rated phase-phase voltage of the potential voltage transformer and
current of the current transformer.
9.1.3.2 Setting of common parameters
GlobalBaseSel : Selects the global base value group used by the function to define ( IBase ), ( VBase )
SBase ).
and (
The settings of negative sequence, zero sequence and delta algorithm are in percent of the global
base voltage and global base current for the function,
The voltage threshold
VSealInPU below the minimum operating voltage that might occur during emergency conditions.
We propose a setting of approximately 70% of the global parameter
The drop off time of 200 ms for dead phase detection makes it recommended to always set
to Enabled since this will secure a fuse failure indication at persistent fuse fail when closing the
local breaker when the line is already energized from the other end. When the remote breaker
closes the voltage will return except in the phase that has a persistent fuse fail. Since the local
breaker is open there is no current and the dead phase indication will persist in the phase with the
blown fuse. When the local breaker closes the current will start to flow and the function detects
the fuse failure situation. But due to the 200 ms drop off timer the output BLKZ will not be
activated until after 200 ms. This means that distance functions are not blocked and due to the
"no voltage but current" situation might issue a trip.
The operation mode selector
requirements. The mode selector makes it possible to select interactions between the negative
sequence and zero sequence algorithm. In normal applications the
for selecting negative sequence algorithm or
studies or field experiences shows that there is a risk that the fuse failure function will not be
activated due to the system conditions, the dependability of the fuse failure function can be
increased if the
negative and zero sequence based algorithm is activated and working in an OR-condition. Also in
OptimZsNs both the negative and zero sequence algorithm are activated and the one that
mode
has the highest magnitude of measured sequence current will operate. If there is a requirement to
increase the security of the fuse failure function
which gives that both negative and zero sequence algorithm is activated working in an AND-
condition, that is, both algorithms must give condition for block in order to activate the output
signals BLKV or BLKZ.
106
VSealInPU is used to identify low voltage condition in the system. Set
OpModeSel has been introduced for better adaptation to system
OpModeSel is set to V0I0 OR V2I2 or OptimZsNs . In mode V0I0 OR V2I2 both the
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VBase and IBase respectively. Set VBase to the primary
VBase and IBase respectively.
V0I0 for zero sequence based algorithm. If system
OpModeSel can be selected to V0I0 AND V2I2 ,
1MRK 505 287-UUS B
IBase to the primary rated
VBase .
OpModeSel is set to either V2I2
Busbar protection REB650
Application manual
M13683-3 v3
M13683-9 v7
SealIn