Siemens siprotec SJ62 User Manual page 267

2 Functions
External Trip Com-
mands
Interaction with
Other Functions
265
The parameters can be set to monitor either exceeding or dropping below of the
threshold. The configurable pickup delay time will be started once the threshold (>-
element) has been exceeded. When the delay time has elapsed and the threshold is
still violated, the pickup of the phase (e.g. no. 235.2122 „$00 pickup A")and of the
function (no. 235.2121 „$00 picked up") is reported. If the pickup delay is set to
zero, the pickup will occur simultaneously with the detection of the threshold violation.
If the function is enabled, the pickup will start the trip delay time and the fault log. This
is not the case if set to "Alarm only". If the threshold violation persists after the trip
delay time has elapsed, the trip will be initiated upon its expiration (no. 235.2126 „$00
TRIP"). The timeout is reported via (no. 235.2125 „$00 Time Out"). Expiry of the
trip delay time can be blocked via binary input (no. 235.2113 „>$00 BLK.TDly").
The delay time will not be started as long as the binary input is active; a trip can thus
be initiated. The delay time is started after the binary input has dropped out and the
pickup is still present. It is also possible to bypass the expiration of the delay time by
activating binary input (no. 235.2111 „>$00 instant."). The trip will be launched
immediately when the pickup is present and the binary input has been activated. The
trip command can be blocked via binary inputs (no. 235.2115 „>$00 BL.TripA")
and (no. 235.2114 „>$00 BLK.TRIP"). The phase-selective blocking of the trip
command is required for interaction with the inrush restraint (see „Interaction with
other functions"). The function's dropout ratio can be set. If the threshold (>-element)
is undershot after the pickup, the dropout delay time will be started. The pickup is
maintained during that time, a started trip delay time continues to count down. If the
trip delay time has elapsed while the dropout delay time is still during, the trip
command will only be given if the current threshold is exceeded. The element will only
drop out when the dropout delay time has elapsed. If the time is set to zero, the
dropout will be initiated immediately once the threshold is undershot.
The logic diagram does not explicitly depict the external trip commands since their
functionality is analogous. If the binary input is activated for external trip commands
(no. 235.2112 „>$00 Dir.TRIP"), it will be logically treated as threshold overshoot-
ing, i.e. once it has been activated, the pickup delay time is started. If the pickup delay
time is set to zero, the pickup condition will be reported immediately starting the trip
delay time. Otherwise, the logic is the same as depicted in Figure 2-90.
The flexible protection functions interact with a number of other functions such as the
• Breaker failure protection:
The breaker failure protection is started automatically if the function initiates a trip.
The trip will, however, only take place if the current criterion is met at this time, i.e.
the set minimum current threshold 212 BkrClosed I MIN (Power System Data
1) has been exceeded.
• Automatic reclosing (AR):
The AR cannot be started directly. In order to interact with the AR, the trip command
of the flexible function needs be linked in CFC to binary input no. 2716 „>Start
79 Ph" or no. 2715.„>Start 79 Gnd". Using an operating time requires the
pickup of the flexible function to be linked to binary input no. 2711 „>79 Start".
• Fuse-Failure-Monitor (see description at „Blocking Functions").
SIPROTEC 4, 7SJ62/63/64 Handbuch
C53000-G1140-C147-A, Edition 07.2015