Siemens SIPROTEC 7SJ61, Руководство пользователя, Страница: 288 / 454

Mounting and Commissioning
3.2 Checking Connections
SIPROTEC, 7SJ61, Manual
C53000-G1140-C210-1, Release date 02.2008
288
3.2.2 Checking 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 should perform the inspection steps.
Caution!
Take care when operating the device without a battery on a battery charger.
Non-observance of the following measures 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 to avoid condensation. Connections are checked
with the device at its final location. The plant must first be switched off and grounded.
Proceed as follows in order to check the system connections:
• Protective switches (e.g. test switches, fuses, or miniature circuit breakers) for the power supply must be
opened.
• Check the continuity of all current 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?
– Is the polarity for current input I
4
correct (if used)?
• If check switches are used for secondary testing of the device, their functions also must be checked, in par-
ticular that in the "check" setting the current transducer secondary lines are automatically shorted.
• 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 continuity. Make sure that terminal continuity is not
wrongly simulated in reverse direction via current transformers or their short-circuiters.
– Remove the front panel of the device
– Remove the ribbon cable connected to the I/O board with the measured current inputs (on the front side
it is the right printed circuit board in Figure 3-3). Then remove the printed circuit board so that there is no
longer any contact with the plug-in terminal of the housing.
– 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.