2 Functions
64
7SD5 Manual
C53000-G1176-C169-1
current balance of the distance protection (in Figure 2-4 for the device at location II),
above which compensation should take place. In general, a presetting of 85 % is suf-
ficient. A more sensitive (larger) setting has no advantage. Only in the case of a severe
system asymmetry, or a very small coupling factor (X
M
/X
L
below approximately 0.4),
may a smaller setting be useful. A more detailed explanation of parallel line compen-
sation can be found in Section 2.5.1 under distance protection.
Figure 2-4
Distance with parallel line compensation at II
The current ratio may also be calculated from the desired distance of the parallel line
compensation and vice versa. The following applies (refer to Figure 2-4):
Current
Transformer
Saturation
7SD5 contains a saturation detector which largely detects the measuring errors result-
ing from the saturation of the current transformers and initiates a switchover to dis-
tance measurement. The threshold above which it picks up can be set in address
1140
I-CTsat. Thres.
. This is the current level above which saturation may be
present. The setting
∞
disables the saturation detector. This parameter can only be
altered with DIGSI
®
under
Additional Settings
. If current transformer saturation is ex-
pected, the following equation may be used as a thumb rule for this setting:
P
N
= Nominal CT burden [VA]
P
i
= Nominal CT internal burden [VA]
P'
= Actual connected burden (protection connection cable)
Circuit Breaker
Status
Information regarding the circuit breaker position is required by various protection and
supplementary functions to ensure their optimal functionality. The device has a circuit
breaker status recognition which processes the status of the circuit breaker auxiliary
contacts and contains also a detection based on the measured currents and voltages
for opening and closing (see also Section 2.23.1).
In address
1130
the residual current
PoleOpenCurrent
is set, which will definitely
not be exceeded when the circuit breaker pole is open. If parasitic currents (e.g.
through induction) can be excluded when the circuit breaker is open, this setting may
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Содержание siprotec 7SD5
Страница 2: ...2 7SD5 Manual C53000 G1176 C169 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 ...
Страница 4: ...4 7SD5 Manual C53000 G1176 C169 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 ...
Страница 18: ...Contents 18 7SD5 Manual C53000 G1176 C169 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 ...
Страница 34: ...1 Introduction 34 7SD5 Manual C53000 G1176 C169 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 ...
Страница 444: ...2 Functions 444 7SD5 Manual C53000 G1176 C169 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 ...
Страница 580: ...4 Technical Data 580 7SD5 Manual C53000 G1176 C169 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 ...
Страница 682: ...Literature 682 7SD5 Manual C53000 G1176 C169 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 ...
Страница 698: ...Index 698 7SD5 Manual C53000 G1176 C169 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 ...