3 Mounting and Commissioning
400
7SA522 Manual
C53000-G1176-C155-3
– Is the polarity for current input I
4
correct (if used)?
– Is the polarity for voltage input U
4
correct (if used, e.g. for broken delta winding
or busbar voltage)?
• Check the functions of all test switches that are installed for the purposes of sec-
ondary testing and isolation of the device. Of particular importance are test switches
in current transformer circuits. Be sure these switches short-circuit the current
transformers when they are in the “test mode”.
• 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. Make sure that terminal continuity is not wrongly simulated in reverse direction
via current transformers or their short circuit links.
– Remove the front panel of the device (see also Figures 3-3 to 3-4).
– Remove the ribbon cable connected to the input/output board with the measured
current inputs (on the front side it is the right PCB, for housing size
1
/
2
see Figure
3-3 slot 33, for housing size
1
/
1
see Figure 3-4 slot 33 right). Furthermore, remove
the PCB so that there is no more contact anymore with the plug-in terminal.
– At the terminals of the device, check continuity for each pair of terminals that re-
ceives current from the CTs.
– Firmly re-insert the I/O board. Carefully connect the ribbon cable. Be careful that
no connector pins are bent! Don't apply 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.
• Connect an ammeter in the supply circuit of the power supply. A range of about 2.5
A to 5 A for the meter is appropriate.
• Switch on m.c.b. for auxiliary voltage (supply protection), check the voltage level
and, if applicable, the polarity of the voltage at the device terminals or at the con-
nection modules.
• The measured steady-state current should correspond to the quiescent power con-
sumption of the device. Transient movement of the ammeter merely indicates the
charging current of capacitors.
• Remove the voltage from the power supply by opening the protective switches.
• Disconnect the measuring test equipment; restore the normal power supply con-
nections.
• Apply voltage to the power supply.
• Close the protective switches for the voltage transformers.
• Verify that the voltage phase rotation at the device terminals is correct.
• Switch off the miniature circuit breakers for the transformer voltage (VT mcb) and
the power supply.
• Check tripping circuits to the circuit breakers.
• Check the close circuits to the power system circuit breakers
• Verify that the control wiring to and from other devices is correct.
• Check the signalling connections.
• Close the protective switches.
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