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Mounting and Commissioning
3.2 Checking 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 connec-
tion diagrams:
–
Are the current transformers grounded properly?
–
Are the polarities of the current transformer connections the same?
–
Is the phase relationship of the current transformers correct?
–
Are the voltage transformers grounded properly?
–
Are the voltage transformers grounded properly?
–
Is the phase relationship of the voltage transformer connections correct?
–
Is the polarity for current input Ι
•
Check the functions of all test switches that are installed for the purposes of secondary testing and isola-
tion 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.
•
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 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
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 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 signaling connections.
•
Switch the mcb back on.
Screw terminals for connection modules:
The connection module is available in 8-pin design for current connections and in 14-pin design for voltage
connections.
[i-u-klemmen-7sx80-071212, 1, --_--]
Figure 3-20
226
4
Current and voltage terminals
correct (if used)?
SIPROTEC 4, 7SD80, Manual
E50417-G1100-C474-A2, Edition 02.2018
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