Siemens SIPROTEC 7SJ80

•
Circuit breakers for the auxiliary power supply and the measuring voltage 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 assignment of the current transformers correct?
– Are the voltage transformers grounded properly?
– Are the polarities of the voltage transformer connections the same and correct?
– Is the phase assignment of the voltage transformers correct?
–
Is the polarity for the current input Ι
N
, Ι
Ns
(if used)?
– Is the polarity for the voltage input V
3
correct (if used e.g. for broken delta winding or busbar
voltage)?
•
If test switches are used for the secondary testing of the device, their functions must also be checked, in
particular that in the “Check” position the current transformer secondary lines are automatically short-
circuited
•
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.
Mounting and Commissioning
3.2 Checking Connections
SIPROTEC 4, 7SJ80, Manual 331
E50417-G1140-C343-A8, Edition 12.2017