Functions
6-296 7SA6 Manual
C53000-G1176-C156-2
6.22.3 Overall Fault Detection Logic of the Device
Phase Segregated
Fault Detection
The fault detection logic combines the fault detection (pick-up) signals of all protection
functions. In the case of those protection functions that allow for phase segregated
pick-up, the pick-up is output per phase. If a protection function detects an earth fault,
this is also output as a common device alarm. The following alarms are therefore avail-
able “
Relay PICKUP L1”, “Relay PICKUP L2”, “Relay PICKUP L3” and “Relay
PICKUP E
”.
The annunciations above can be allocated to LEDs or output relays. For the local dis-
play of fault event messages (trip log) and for the transmission of event messages to
a personal computer or a centralized control system, several protection functions pro-
vide the possibility to display the faulted phase information in a single message, e.g.
“
Dis.Pickup L12E”forthedistanceprotectionfaultdetectioninL1–L2–Eonlyone
such messages appears. It represents the complete definition of the fault detection.
General Fault
Detection
All fault detection signals are combined with a logic OR function and cause a general
fault detection of the device. It is designated with “
Relay PICKUP”. If no protection
function is picked-up anymore, the “
Relay PICKUP” will reset (message “Going”).
The general fault detection is a prerequisite for a number of internal and external con-
sequential functions. The following belong to the internal functions which are control-
led by the general fault detection:
• Initiation of a fault event report (trip log): from the pick-up to the reset of the general
fault detection the fault messages are stored in the trip log.
• Initialisation of the fault recording: the storage of analogue and binary traces can
additionally be made dependant on the appearance of a trip command.
• Generation of spontaneous messages. Certain fault messages may appear in the
display of the device as so called spontaneous messages (see “Spontaneous Mes-
sages” below). This display may additionally be made dependant on the appear-
ance of a trip command.
• Start action time of automatic reclosure (if available and used)
External functions may be controlled via an output contact. The following are exam-
ples:
• Automatic reclose devices,
• Channel boost in conjunction with signal transmission by PLC,
• Initiation of further supplementary devices etc.
Spontaneous
Messages
Spontaneous messages are fault messages which appear in the display automatically
following a general fault detection of the device or trip command. In the 7SA6 these
are:
• “Relay PICKUP”: protection function which picked up most recently;
• ”Relay TRIP”: protection function which tripped (only device with graphic
display);
• “PU Time”: thedurationfrompickuptoresetofthegeneralfault
detection of the device; the time is indicated in ms;
• “TRIP Time”: thedurationfrompickuptotheofthefirsttripcommandofthe
device; the time is indicated in ms;
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