Siemens SIPROTEC 7SJ61 Manual page 157

The message „IIE Fault det" will be entered in the fault log and reported to the system interface only until
the message „Intermitt.EF" is issued. This prevents a burst of messages. If the message is allocated to
an LED or a relay, this limitation does not apply. This is accomplished by doubling the message (message
numbers 6924, 6926).
Interaction with the Automatic Reclosure Function
Automatic reclosure is not an effective measure against intermittent ground faults as the function only trips after
repeated detection of a fault or after expiration of the summation monitoring time T-sum det. and besides
this, its basic design is to prevent thermal overload. For these reasons, the intermittent ground fault protection
is not implemented as starting feature of the automatic reclosing function.
Interaction with Breaker Failure Protection
A pickup that is present when the time delay TRIP-Timer has expired is interpreted by the breaker failure pro-
tection as a criterion for a tripping failure. Since permanent pickup is not ensured after a tripping command by
the intermittent ground fault protection, cooperation with the breaker failure protection is not sensible. There-
fore, this function is not activated by the intermittent ground fault protection.
Logic Diagram
The following figure shows the logic diagram for the intermittent ground fault protection function.
SIPROTEC, 7SJ61, Manual
C53000-G1140-C210-1, Release date 02.2008
2.10 Intermittent Ground Fault Protection
Functions
157