Mounting and Commissioning
3.2 Checking Connections
SIPROTEC, 7SD5, Manual
C53000-G1176-C169-5, Release date 02.2011
529
3.2.3
Checking the System Connections
WARNING!
Warning of dangerous voltages
Non-observance of the following measures can result in death, personal injury or substantial property damage.
Therefore, only qualified people who are familiar with and adhere to the safety procedures and precautionary
measures shall perform the inspection steps.
Caution!
Be careful when operating the device on a battery charger without a battery
Non-observance of the following measure can lead to unusually high voltages and consequently, the destruc-
tion of the device.
Do not operate the device on a battery charger without a connected battery. (For limit values see also Technical
Data, Section 4.1).
Before the device is energized for the first time, it should be in the final operating environment for at least 2
hours to equalize the temperature, to minimize humidity and avoid condensation. Connections are checked
with the device at its final location. The plant must first be switched off and earthed.
Connection examples for current transformer connections are provided in the Appendix A.3. Please observe
the plant diagrams, too.
Proceed as follows in order to check the system connections:
• Protective switches for the power supply and the measured voltages must be opened.
• Check the continuity of all current and voltage transformer connections against the system and connection
diagrams:
– Are the current transformers earthed correctly?
– Are the polarities of the current transformers the same?
– Is the phase relationship of the current transformers correct?
– Are the voltage transformers earthed correctly (if used)?
– Are the polarities of the voltage transformers correct (if used)?
– Is the phase relationship of the voltage transformers correct (if used)?
– Is the polarity for current input
I
4
correct (if used)?
– Is the polarity for voltage input U
4
correct (if used, e.g. with open delta winding or busbar voltage)?
• Check the functions of all test switches that are installed for the purposes of secondary testing and isolation
of the device. Of particular importance are test switches in current transformer circuits. Be sure these switch-
es short-circuit the current transformers when they are in the „test mode“.
