Functions
2.24 Monitoring Functions
SIPROTEC, 7SD5, Manual
C53000-G1176-C169-5, Release date 02.2011
432
Figure 2-213
Logic of the Positive Sequence System Phase Angle Monitoring
2.24.1.5 Fault Reactions
Depending on the kind of fault detected, an alarm is given, the processor is restarted or the device is taken out
of operation. After three unsuccessful restart attempts, the device is taken out of service. The device ready
relay drops out and indicates the device failure with its NC contact („life contact“). The red LED „ERROR“ on
the device front lights up, provided that there is an internal auxiliary voltage, and the green LED „RUN“ goes
off. If the internal auxiliary voltage supply fails, all LEDs are dark. Table 2-17 shows a summary of the monitor-
ing functions and the malfunction responses of the device.