Built-In Restraints - Siemens SICAM Manual

5.6 Built-in Restraints
SICAM EFI is provided with the following built-in restraint functionalities to prevent false ground-fault indica-
tion.
Ground-current Inrush Detection
Whenever a line is energized, due to transformer magnetization, an inrush current is drawn by the trans-
former. This current is transient in nature and remains for a few milliseconds (also called as the inrush period).
To avoid incorrect ground-fault indication due to inrush current, a time delay is introduced before activation of
the fault indication.
At the end of the inrush period, SICAM EFI checks the voltage availability confirmation by sensing the AC BI
input. A fault (single or continuous) is indicated if the AC BI signal is not available and no fault (single or
continuous) is indicated if the AC BI signal is available.
Thus the device eliminates the possibility of a false fault detection due to inrush current and only indicates
actual faults to the user.
The ground-current inrush detection time can be configured as Disable, 300 ms and 1 s.
By default, this functionality is disabled in the device. Refer to 5.4.8 Ground-current Inrush on how to enable
this functionality and for configuring the inrush-current detection time.
Auto-Reclosure
The auto-reclosure function is used to block the redundant ground-fault detection and indication during the
auto-reclosure retries which are made to restore the ground current.
After a fault, the line/network is cut off and auto-reclosure retries are made to restore the line/network. The
device can detect new faults based on the auto-reclosure retries.
In such case, when auto-reclosure functionality is enabled in SICAM EFI, the device blocks such redundant
fault detection for the configured auto-reclosure time. The auto-reclosure time can be configured as Disable
or 3 min.
When the auto-reclosure functionality is enabled in the device and a fault is indicated, then for 3 min, SICAM
EFI does not accept any type of fault reset requests except Push-button reset.
By default, this functionality is disabled in the device. Refer to 5.4.7 Auto Reclosure Time Setting on how to
enable this functionality and for configuring the auto reclosure time.
SICAM, Earth Fault Indicator, Manual
E50417-H8940-C600-A3, Edition 12.2022
Device Functions
5.6 Built-in Restraints
71