Overall Fault Detection Logic Of The Device - Siemens siprotec 7SA522 User Manual

6.17.3 Overall Fault Detection Logic of the Device

Phase Segregated
Fault Detection
General Fault
Detection
Spontaneous
Messages
7SA522 Manual
C53000-G1176-C119-2
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 in a phase segregated manner. If a protection function
detects an earth fault, this is also output as a common device alarm. The following
alarms are therefore available "5HOD\ 3,&.83 /", "5HOD\ 3,&.83 /", "5HOD\
3,&.83 /" and "5HOD\ 3,&.83 (".
The annunciations above can be allocated to LEDs or output relays. For the local dis-
play of fault event messages and for the transmission of event messages to a personal
computer or a centralized control system, several protection functions provide the pos-
sibility to display the faulted phase information in a single message, e.g.
"'LV3LFNXS /(" for the distance protection fault detection in L1–L2–E only one
such messages appears. It represents the complete definition of the 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 "5HOD\ 3,&.83". If no protection
function is picked-up anymore, the "5HOD\ 3,&.83" 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: from the pick-up to the reset of the general fault de-
tection the fault messages are stored in the fault event recording.
• 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 are fault messages which appear in the display automatically
following a general fault detection of the device or trip command. In the 7SA522 these
are:
• "5HOD\ 3,&.83": protection function which picked up most recently;
• "38 7LPH":
• "75,3 7LPH":
the duration of the general fault detection up to the reset of
the device; the time is indicated in ms;
the duration of the general fault detection up to the occurrence
of the first trip command of the device; the time is indicated
in ms;
Functions
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