Siemens SIPROTEC 6MD665, Manual

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3.2 Checking Connections
115
6MD665 Manual
C53000-G1876-C103-3
WARNING!
Warning of dangerous voltages
Non-observance of the following measures can result in death, personal injury or sub-
stantial property damage.
Therefore, only qualified people who are familiar with and adhere to the safety proce-
dures 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 destruction of the device.
Do not operate the device on a battery charger without a connected battery. (Limit
values can be found in the technical data).
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 grounded properly?
– Are the polarities of the current transformers the same?
– Is the phase relationship of the current transformers correct?
– Are the voltage transformers grounded properly?
– Are the polarities of the voltage transformers correct?
– Is the phase relationship of the voltage transformers correct?
– Is the polarity for current input IE correct (if used)?
– Is the polarity for voltage input UE correct (if used for broken delta winding)?
• The short-circuit feature of the current circuits of the device are to be checked. This
may be performed with an ohmmeter or other test equipment for checking continu-
ity.
– Remove the screws of the front cover
– Remove the ribbon cable connected to the I/O-5 board and pull the board out
until there is no contact between the board and the rear connections of the
device.
– At the terminals of the device, check continuity for each pair of terminals that
receives current from the CTs.
– Firmly re-insert the I/O board. Carefully connect the ribbon cable. Do not bend
any connector pins! Do not use force!
– At the terminals of the device, again check continuity for each pair of terminals
that receives current from the CTs.
– Attach the front panel and tighten the screws.