Siemens SIPROTEC 7SS523 V3.2 Manual page 286

Installation and Commissioning
7.4 Checks With Secondary Values
7.4.1 General
270
The operational preparations according to Chapter 7.2, page 251 must be completed.
Warning!
Hazardous voltages are present in this electrical equipment during operation. Severe
personal injury or property damage can result if the device is not handled properly.
Only qualified personnel may work on and around this equipment after becoming thor-
oughly familiar with all warnings and safety notices in this instruction manual as well
as with the applicable safety steps, safety regulations, and precautionary measures.
The main points to observe are:
• The device is to be earthed to the substation earth before any other connections
are made.
• Hazardous voltages can exist in the power supply and at the connections to current
transformers, voltage transformers, and test circuits.
• Hazardous voltages can be present in the device even after the power supply
voltage has been removed, i.e. capacitors can still be charged.
• The limit values given in Chapter 9, page 301 "Technical Data", must not be
exceeded, neither during testing nor during commissioning.
DANGER!
The output terminals of the current transformers must be short-circuited on the trans-
formers themselves before the power supply lines to the bay unit are disconnected.
Where a test switch is available that short-circuits automatically the output lines of the
current transformer, it will be sufficient to set it to "Test" position, provided that the
short-circuiters have been checked in the first place.
It is recommended to make the checks with secondary values at the current settings
for the protection system. If these are not available make the checks with the default
values (Chapter 5, page 91). For the following descriptions of the checks the default
values are the basis if not noted differently. As far as it is necessary, for other setting
values formulas are given.
Because of the phase-selective measuring principle for the testing two 1-phase, sep-
arately controllable current sources are sufficient.
7SS52 V4 Manual
C53000-G1176-C182-1