Supervisory Functions
141
7SS52 V4 Manual
C53000-G1176-C182-3
Bay unit failure All serial links between the bay unit and the central unit are continuously monitored in
the central unit. A failure or disturbance of an operating bay unit leads to the output of
an alarm but not to a system reset. The same is true for a failure or disturbance of the
link between bay unit and central unit.
If the connection fails, the protection is blocked in accordance with the settings of the
parameter BLOCKING MODE (6305/CU), either selectively for the zone for which the
respective bay unit is switched and, if required, for the phase, or completely.
Measured value er-
rors
The analog inputs of the bay unit are cyclically monitored (Chapter 5.5.1.3, page 142).
The measured value error consists of the offset monitoring and the current sum mon-
itoring. Furthermore, the measured values read in with gain 1 and 16 are checked for
plausibility to each other. If one of these errors occurs, the protection is immediately
blocked - selectively or entirely - and the error is signalled. If the error has been
present longer than 1 s, the blocking is permanent and can only be reset with a warm
restart.
Figure 5-32 Simplified logic of the monitoring function
Isolator malfunc-
tion
Isolators are monitored with regard to runtime, isolator status plausibility and auxiliary
voltage. An isolator malfunction with the parameter ISOL Malfunct (6302/CU) set
to blocking and the parameter BLOCKING MODE (6305/CU) set to zone/phase
causes a blocking of only the protection zone to which the feeder with the faulty isola-
tor is connected.
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