3 Mounting and Commissioning
290
7SD610 Manual
C53000-G1176-C145-4
– 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 broken delta wind-
ing)?
• 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-circuiters of the plug connectors for the current circuits must be checked.
This may be performed with secondary test equipment 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 (see Figure 3-3).
– Remove the ribbon cable connected to the I/O board (viewed from the front side
it is the respective circuit board on the right, see Figure 3-3). Then remove the
printed circuit board so that there is no longer any contact with the plug-in termi-
nal of the housing.
– 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.
• Open 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.
• If communication converters are used: check the auxiliary voltages for the commu-
nication converters.
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