Overall Fault Detection Logic Of The Device - Siemens siprotec 7SA6 User Manual

Functions

6.20.3 Overall Fault Detection Logic of the Device

Phase Segregated
Fault Detection
General Fault
Detection
Spontaneous
Messages
6-272
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
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
display 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
provide the possibility 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
consequential functions. The following belong to the internal functions which are
controlled 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
Messages" below). This display may additionally be made dependant on the
appearance 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
examples:
• 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 7SA6 these
are:
• "5HOD\ 3,&.83": protection function which picked up most recently;
• "5HOD\ 75,3":
• "38 7LPH":
• "75,3 7LPH":
protection function which tripped (only device with graphic
display);
the duration from pickup to reset of the general fault
detection of the device; the time is indicated in ms;
the duration from pickup to the of the first trip command of the
device; the time is indicated in ms;
7SA6 Manual
C53000-G1176-C133-1