Siemens siprotec SJ62 User Manual page 223

2 Functions
Interaction with the
Automatic Reclo-
sure Function
Interaction with
Breaker Failure
Protection
221
are reset and the protection returns to its quiescent state. T-reset thus determines
the time during which the next ground fault must occur to be processed yet as inter-
mittent ground fault in connection with the previous fault. A ground fault that occurs
later will be considered a new fault event.
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).
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 sum-
mation 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 im-
plemented as starting feature of the automatic reclosing function.
A pickup that is present when the time delay TRIP-Timer has expired is interpreted
by the breaker failure protection as a criterion for a tripping failure. Since permanent
pickup is not ensured after a tripping command by the intermittent ground fault protec-
tion, cooperation with the breaker failure protection is not sensible. Therefore, this
function is not activated by the intermittent ground fault protection.
SIPROTEC 4, 7SJ62/63/64 Handbuch
C53000-G1140-C147-A, Edition 07.2015