Settings - Siemens siprotec 7SA6 User Manual

Stub Protection
6.9.3

Settings

Addr. Setting Title
2601 Operating Mode
2680 SOTF Time DELAY
2610 Iph>>
2611 T Iph>>
2612 3I0>> PICKUP
2613 T 3I0>>
2614 I>> Telep/BI
2615 I>> SOTF
2620 Iph>
2621 T Iph>
2622 3I0>
2623 T 3I0>
7SA6 Manual
C53000-G1176-C133-1
When using the I STUB protection the pick-up thresholds ,SK! 678% (address )
and ,! 678% (address ) are usually not critical, as this protection function is
only activated when the line isolator is open which implies that every measured current
should represents a fault current. With a 1
Figure 6-85 it is possible that large short circuit currents flow from busbar A to busbar
B or to feeder 2 via the current transformers. These currents could cause different
transformation errors in the two current transformer sets I
saturation range. The protection should therefore not be set unnecessarily sensitive.
If the minimum short circuit currents on the busbars are known, the pick-up threshold
,SK! 678% is set somewhat (approx. 10 %) below the minimum two phase short
circuit current, ,! 678% is set below the minimum single-phase current.
The time settings 7 ,SK 678% (address ) and 7 , 678% (address ) are
set to 0 for this application, to ensure rapid clearance of a stub fault when the line
isolator is open.
If this stage is applied differently, similar considerations as for the other overcurrent
stages apply.
If the ,6WXE-stage is to trip when switching the line on to a fault with or without a
short delay, 627) 7LPH '(/$< (address , see above and refer to Sub-section
"General"), the parameter ,678% 627) (address ) is set to <(6. If using the
stub protection, then set to 12 as the effect of this protection function only depends on
the position of the isolator.
Note: The indicated secondary current values for setting ranges and default settings
refer to I = 1 A. For the nominal current 5 A the current values are to be multiplied
N
by 5.
Setting Options
ON
Only Active with Loss of VT
sec. circuit
OFF
0.00..30.00 sec
0.10..25.00 A; ∞
0.00..30.00 sec; ∞
0.05..25.00 A; ∞
0.00..30.00 sec; ∞
NO
YES
NO
YES
0.10..25.00 A; ∞
0.00..30.00 sec; ∞
0.05..25.00 A; ∞
0.00..30.00 sec; ∞
1
/ –circuit breaker arrangement similar to
2
A
Default Setting
Only Active with Operating mode
Loss of VT sec. cir-
cuit
0.00 sec Trip time delay after SOTF
2.00 A Iph>> Pickup
0.30 sec T Iph>> Time delay
0.50 A 3I0>> Pickup
2.00 sec T 3I0>> Time delay
YES Instantaneous trip via Teleprot./
BI
NO Instantaneous trip after Switch-
OnToFault
1.50 A Iph> Pickup
0.50 sec T Iph> Time delay
0.20 A 3I0> Pickup
2.00 sec T 3I0> Time delay
Functions
and I , especially in the
B
Comments
6-153