Siemens 7SJ85 - Application and Setting Notes; Parameter

•
V0
•
φ (IN, V0)
Application and Setting Notes
Indication: Ground fault
To indicate the ground fault and its direction via the protocol, Siemens recommends using the indication (_:
2311:302) Ground fault . The indication contains the direction information, independent of the parame-
terized working direction of a stage. And this indication is also stabilized against a flood of indications in case
of an intermittent ground fault.
Parameter: Decay time V0
•
Recommended setting value (_:2311:101) Decay time V0 = 0.10 s
With the Decay time V0 parameter, you specify the time slot for the detection of a fault extinction. If V0
continuously falls within this time, fault extinction is detected and the indication
Flt. extinction det. is
issued.
Siemens recommends using the default setting.
Parameter: Dropout delay
•
Recommended setting value (_:2311:102) Dropout delay = 1.00 s
To avoid chattering of the indication
Ground fault during an intermittent ground fault and thus a frequent
opening and closing of the ground-fault log, the dropout of the indication Ground fault (and thus the
closing of the log) can be delayed by the Dropout delay.
Siemens recommends using the default setting.
Using the default setting ensures that no flood of indications arises in case of an intermittent ground fault for
the indication Ground fault . The intermittent ground fault is then treated as a ground fault, and the stabili-
zation of the indication Ground fault can thus take action.
Angle-Error Compensation of the Core Balance Current Transformer
•
Default setting (_:2311:103) Core balance CT- current 1 = 0.050 A
•
Default setting (_:2311:104) Core balance CT- current 2 = 1.000 A
•
Default setting (_:2311:105) CT angle error at I1 = 0.0°
•
Default setting (_:2311:106) CT angle error at I2 = 0.0°
The high reactive-power factor in the arc-suppression-coil-ground system and the unavoidable air gap of the
core balance current transformer often make necessary a compensation of the angle error of the core balance
current transformer. For the burden actually connected, the maximum angle error CT angle error at I1
and the corresponding secondary current Core balance CT- current 1 as well as a further operating
point CT angle error at I2/Core balance CT- current 2 are entered, from which point the angle
error no longer changes appreciably.
In the isolated or grounded system, angle compensation is not necessary.
Parameter
Addr.
Parameter C Setting Options Default Setting
General
_:2311:101 General:Decay time V0 0.06 s to 0.20 s 0.10 s
_:2311:102 General:Dropout delay 0.00 s to 60.00 s 1.00 s
6.15.3.2
6.15.3.3
Protection and Automation Functions
6.15 Sensitive Ground-Fault Detection
SIPROTEC 5, Overcurrent Protection, Manual 567
C53000-G5040-C017-8, Edition 07.2017