Table of Contents
Advertisement
Functions
2.1 General
Example:
Phase current transformers 500 A / 5 A
Earth current transformer 60 A / 1 A
• Connection of the I
tance protection and/or fault location):
Address 220 is then set to: I4 transformer = In paral. line and usually address 221 I4/Iph CT
= 1.
If the set of current transformers on the parallel line however has a different transformation ratio to those on
the protected line, this must be taken into account in address 221:
Address 220 is then set to: I4 transformer = In paral. line and address 221 I4/Iph CT = I
/ I
line
N prot. line
Example:
Current transformers on protected line 1200 A
Current transformers on parallel line 1500 A
• Connection of the I
restricted earth fault protection and occasionally for the polarisation of the directional earth fault protection:
Address 220 is then set to: I4 transformer = IY starpoint, and address 221 I4/Iph CT is accord-
ing to transformation ratio of the starpoint transformer to the transformer set of the protected line.
• If the input I
Address 220 I4 transformer = Not connected,
Address 221 I4/Iph CT is then irrelevant.
In this case, the neutral current is calculated from the sum of the phase currents.
Rated frequency
The rated frequency of the power system is set under address 230 Rated Frequency. The factory presetting
according to the ordering code (MLFB) only needs to be changed if the device is applied in a region different
from the one indicated when ordering. You can set 50 Hz or 60 Hz.
System starpoint
If the distance protection has been configured as the main protection function or in combination with differential
protection, 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 207 SystemStarpoint = Solid
Earthed, Peterson-Coil or Isolated. For „low-resistant" earthed systems set Solid Earthed.
48
input to the earth current of the parallel line (for parallel line compensation of the dis-
4
input to the starpoint current of a transformer; this connection is always used for the
4
is not required, set:
4
SIPROTEC, 7SD5, Manual
C53000-G1176-C169-5, Release date 02.2011
N paral.
Advertisement
Table of Contents
