Siemens 7SJ82 Manual page 625

EXAMPLE
Clocking device:
Set pulse-on duration for the clocking device
Max. tolerance pulse-on duration of the clocking device
Set pulse-off duration for the clocking device
Max. tolerance pulse-off duration of the clocking device
Larger tolerance of both
Tolerance to be set:
Tolerance of the SIPROTEC 5 device
Total tolerance to be set
Consequently, you must set the respective device settings as:
•
Pulse-on duration = 1.00 s
•
Pulse-off duration = 1.50 s
•
Max.tolera.pulse-on or off = 0.15 s
The following figure shows the measured pulse durations which are within the maximum stated tolerances of
the example.
[dw_tolerance, 1, en_US]
If you have no information about the tolerance of the clocking device, you can carry out a test recording while
the clocking device is in operation. From the test recording, you can read the inaccuracy of the pulse-on/pulse-
off durations. Add a safety margin of 20 ms on the read inaccuracy and consider this as the maximum toler-
ance of the clocking device. For the setting, add another 40 ms for the tolerance of the SIPROTEC 5 device.
Parameter: 3I0 delta pulse off-on
•
Default setting (_:103) 3I0 delta pulse off-on = 10 %
With the 3I0 delta pulse off-on parameter, you define the minimum percentage value of the ground-
current delta between the capacitor switched-on and capacitor switched-off states to detect the pulse pattern.
That is, to detect the pulse pattern, the following condition must be met:
[fo_delta ratio, 1, en_US]
SIPROTEC 5, Overcurrent Protection, Manual
C53000-G5040-C017-8, Edition 07.2017
Protection and Automation Functions
6.15 Sensitive Ground-Fault Detection
1.00 s
70 ms
1.50 s
110 ms
110 ms
40 ms
110 ms + 40 ms = 150 ms
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