Siemens SIPROTEC 7SS523 V3.2 Manual page 301

8.2.2 Checking the Auxiliary Voltage Supply
8.2.3 Checking the LEDs on the Modules
If failures are detected in the bay unit, they are indicated with their bay number.
It is then possible to locate the failure more precisely within the bay. Operational
events which support identification of a failure are e.g.:
• Disturbance of the power supply
• Failure detection by the measured value supervision
The alarm of auxiliary voltage failure in the protection device can be caused by a
device failure as well as by disturbances in the external wiring.
It should be checked whether:
− the auxiliary voltage can be measured with adequate magnitude and correct
polarity.
− the ON/OFF switch for the integrated converter is in ON position (this switch can
be found on the front panel of the bay unit 7SS523 or behind the front panel of
the central unit).
− the modules are correctly fitted and locked.
− the fuses in the power supply section of the central unit (module SV) or the bay
unit (module SAF or SVW ) have not blown.
You will find an explanation of the LED indication of the power supply module in the
central unit in Chapter 8.2.3, page 285.
The processor modules ZPS-SBK, ZPS-BSZ, ZPS-SK in the central unit and the
power supply (module SV) are equipped with LED indications which are only visible
after opening the front panel of the central unit.
Warning!
For testing and commissioning, the ruling safety regulations for working in high-
voltage installations have to be obeyed.
The following inspection steps are performed in the presence of dangerous voltages.
Only appropriately qualified personnel familiar with and adhering to safety
requirements and precautionary measures may perform these steps.
5 LEDs are located vertically on the central processor modules (ZPS). Here is a
description of what their indications mean.
7SS52 V4 Manual
C53000-G1176-C182-1
Fault Analysis
285