Setting Notes - Siemens SIPROTEC 4 7SD80 Manual

[lo-pvl-anr-iso-gel-netz-20110608, 1, en_US]
Figure 2-9
You will find the logic diagram for the general pickup of the differential protection and the differential protec-
tion tripping in Section
2.2.2.2

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:
= 2π · f · C
Ι
C Nom
where
Ι
C
f
Nom
C '
B
V
Nom
s
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
SIPROTEC 4, 7SD80, Manual
E50417-G1100-C474-A2, Edition 02.2018
Phase comparison protection in resonant-grounded/isolated systems
2.2.5 Differential Protection Pickup Logic and Tripping
' · s · V /√3
B Nom
2.2 Phase Comparison Protection and Ground Differential Protection
Charging current in A
Rated power system frequency in Hz
Referred rated capacitance of the line in F/km
Rated system voltage in V
Line length in km
Functions
Logic.
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