'(&)( )'&&)( & & !)& &$(($#
Ć
%&($# "#)! &&#$
Appendix
A
A - 11
Siemens AG
⋅
May 1998
A.1.3 Basis for selection of the stabilization factor k
Step 1:
The relationship between the point (in time) at which
saturation occurs andthe stabilisation factor is estabĆ
lished.
The following condition must be fulfilled in order to
prevent bus zone tripping for an external fault
(refer fig A.9.1)
2
K
sin
w
T
S .
K >
K
(c1)
2 sin
w
T
S .
K > 1
(c2)
K
T
S
Figure A.9.1 Short-circuit on a feeder with CT saturation
To determine the point in time T
s
at which saturation
occurs, the burden factor u must be considered.
T
S
sat
K
=u
sat
A
B
Figure A.9.2 Current/time characteristic
If the CT is burdened with
K
=u
sat
, then it will satuĆ
rate after time T
S
whereby area A
ÇÇ
= area B
ÉÉ
(c3)
u (1-cos
w
T
S
) = 2
(c4)
If equations c2 andc4 are combined, then:
K > U/4
Uć1
Ǹ
(c5),
The stabilization factor must be chosen according to
condition c5.
i.Ă e.Ă
w
Ts
ŕ
0
K
Ă sinĂ
w
tĂ
+
Ă
p
ŕ
Ă Ă
Ă
0
sat
Ă sinĂ
w
tĂ
www
. ElectricalPartManuals
. com
Summary of Contents for SIPROTEC 7SS52
Page 1: ... w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Page 2: ...w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Page 3: ... Siemens AG 1998 w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Page 6: ... w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Page 17: ... w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Page 33: ... w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Page 34: ... w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Page 35: ... w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Page 36: ... w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Page 44: ... w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Page 166: ... w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Page 168: ... w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Page 170: ... w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Page 184: ... 1 w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Page 186: ... w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Page 202: ... 0 0 0 w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Page 206: ... X w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Page 208: ...w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Page 209: ...w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Page 210: ... w w w E l e c t r i c a l P a r t M a n u a l s c o m ...