Siemens SIPROTEC 7SA522 Manual page 43

Rated Frequency
System Starpoint
Phase Rotation
Distance Unit
7SA522 Manual
C53000-G1176-C155-3
Example:
Phase current transformers 500 A/5 A
Core balance CT 60 A/1 A
• Connection of the I input to the earth current of a parallel line (for parallel line com-
4
pensation of the distance protection and/or fault location):
Address  is then set to: , WUDQVIRUPHU = ,Q SDUDO OLQH and usually
address  ,,SK &7 = 1.
If the set of current transformers on the parallel line however has a different trans-
formation ratio to those on the protected line, this must be taken into account in
address :
Address  is then set to: , WUDQVIRUPHU = ,Q SDUDO OLQH and address
 ,,SK &7 = I
N paral. line
Example:
Current transformers on protected line 1200 A
Current transformers on parallel line 1500 A
• Connection of the I
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is occasionally used for the polarisation of the directional earth fault protection:
Address  is then set to: , WUDQVIRUPHU = ,< VWDUSRLQW, and address 
,,SK &7 is according to transformation ratio of the starpoint transformer to the
transformer set of the protected line.
• If the I input is not required, set:
4
Address  , WUDQVIRUPHU = 1RW FRQQHFWHG,
Address  ,,SK &7 is then irrelevant.
In this case, the neutral current is calculated from the sum of the phase currents.
The nominal frequency of the system is set in address  5DWHG )UHTXHQF\. The
presetting according to the ordering code (MLFB) only needs to be changed if the
device is applied in a region different to the one indicated when ordering. You can set
 +] or  +].
The manner in which the system starpoint is earthed must be considered for the
correct processing of earth faults and double earth faults. Accordingly, set for address
 6\VWHP6WDUSRLQW = 6ROLG (DUWKHG, 3HWHUVRQ&RLO or ,VRODWHG. For
low-resistant earthed systems set 6ROLG (DUWKHG.
Use address  3+$6( 6(4 to change the default setting (/ / / for clockwise
rotation) if your power system has a permanent anti-clockwise phase sequence (/
/ /).
Address  'LVWDQFH 8QLW determines the distance unit (NP or 0LOHV) for the
fault location indications. This parameter is not relevant if fault detection is not avail-
able. Changing the distance unit will not result in an automatic conversion of the
/ I
N prot. line
input to the starpoint current of a transformer; this connection
2.1 General
43