[lo-pvl-anr-iso-gel-netz-20110608, 1, en_US]
Figure 2-9
Phase comparison protection in resonant-grounded/isolated systems
You will find the logic diagram for the general pickup of the differential protection and the differential protec-
tion tripping in Section
2.2.5 Differential Protection Pickup Logic and Tripping Logic
Setting Notes
General
The phase comparison protection can be switched
ON
or
OFF
at address 1201
87L PCC-Prot.
. This requires
the differential protection to be set to
Enabled
at address 112
87 DIFF.PROTEC.
.
For cables and long lines, the capacitive charging current is decisive for determining the pickup values. The
charging current is calculated as follows:
Ι
C
= 2π · f
Nom
· C
B
' · s · V
Nom
/√3
where
Ι
C
Charging current in A
f
Nom
Rated power system frequency in Hz
C
B
'
Referred rated capacitance of the line in F/km
V
Nom
Rated system voltage in V
s
Line length in km
Pickup Values for Resistive or Solid Grounded, Resonant-grounded and Isolated Systems
At address 1202
87L Idyn>
you can set the dynamic tripping threshold. The value for
87L Idyn>
should be
set to at least 0.2 of the largest primary transformer rated current and larger than 2.5 to 3 times the capacitive
charging current of the line. If inductances can be connected in the protected zone (common-mode reactor)
for energized lines,
87L Idyn>
should be greater than the maximum expected inrush current.
The dynamic tripping threshold for closing is set in address 1203
87L Idyn close>
. The value for
87L
Idyn close>
should be ≥
87L Idyn>
, but it should equal at least 3 times the value of the capacitive
charging current of the protected line. If inductances are present in the protected zone (common-mode
reactor),
87L Idyn close>
should be set greater than the maximum expected inrush current.
The static tripping threshold is set in address 1204
87L Isteady>
. The static tripping threshold should be set
to a value that is larger than at least 3 times the capacitive charging current of the line. If inductances are
2.2.2.2
Functions
2.2 Phase Comparison Protection and Ground Differential Protection
SIPROTEC 4, 7SD80, Manual
53
E50417-G1100-C474-A2, Edition 02.2018
Summary of Contents for SIPROTEC 4 7SD80
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