Mounting and Commissioning
3.2 Checking Connections
SIPROTEC, 7SJ62/64, Manual
C53000-G1140-C207-2, Release date 01.2008
442
• The short-circuiters of the current circuits of the device have to 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
– 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). Furthermore, remove the printed circuit board so that there is no more
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.
• 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 po-
larity of the voltage at the device terminals or at the connection modules.
• The current input should correspond to the power input in neutral position of the device. The measured
steady state current should be insignificant. Transient movement of the ammeter merely indicates the charg-
ing 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 connections.
• 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 protective switches for the voltage transformers and the power supply.
• Check the trip and close circuits to the power system circuit breakers.
• Verify that the control wiring to and from other devices is correct.
• Check the signalling connections.
• Switch the mcb back on.
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