Settings - Siemens SIPROTEC 4 7VK61 Manual

Functions
2.5 Under and over-voltage protection (optional)
If the voltage transformers are located on the line side, the measuring voltages will be missing when the line is
disconnected. To avoid that the undervoltage levels in these cases are or remain picked up, the current crite-
rion CURR.SUP.Uphph< (address 3768) is switched ON. With busbar side voltage transformers it can be
switched OFF. However, if the busbar is dead, the undervoltage protection will pick up and expire and then
remain in a picked-up state. It must therefore be ensured in such cases that the protection is blocked by a
binary input.
If the 7VK61 is operated without current transformer connection, the current criterion is of no use and associ-
ated parameters are hidden.
Undervoltage positive sequence systemU
The positive sequence undervoltage stages can be used instead of or in addition to previously mentioned
undervoltage stages. Depending on your choice, set address 3771 U1<(<) to ON, OFF, Alarm Only or
U<Alarm U<<Trip.
Basically, the same considerations apply as for the other undervoltage stages. Especially in case of stability
problems, the positive sequence system is advantageous, since the positive sequence system is relevant for
the limit of the stable energy transmission.
To achieve the two-stage condition, the U1< stage (address 3772) is combined with a greater time delay T
U1< (address 3773), and the U1<< stage (address U1<<) with a shorter time delay TT U1<< (address 3775).
Note that the positive sequence system is calculated according to its defining equation
U = 1 / ·|U + a·U
1 3 L1
The dropout to pickup ratio U1<(<) RESET can be set in address 3779. This parameter can only be altered in
DIGSI at Display Additional Settings.
If the voltage transformers are located on the line side, the measuring voltages will be missing when the line is
disconnected. To avoid that the undervoltage levels in these cases are or remain picked up, the current crite-
rion CURR.SUP.U1< (address 3778) is switched ON. With busbar side voltage transformers it can be switched
OFF. However, if the busbar is dead, the undervoltage protection will pick up and expire and then remain in a
pickedup state. It must therefore be ensured in such cases that the protection is blocked by a binary input.
If the 7VK61 is operated without current transformer connection, the current criterion is of no use and associ-
ated parameters are hidden.

Settings

2.5.4
Addresses which have an appended "A" can only be changed with DIGSI, under "Additional Settings".
Addr. Parameter
3701 Uph-e>(>)
3702 Uph-e>
3703 T Uph-e>
3704 Uph-e>>
3705 T Uph-e>>
3709A Uph-e>(>) RESET
3711 Uph-ph>(>)
3712 Uph-ph>
3713 T Uph-ph>
3714 Uph-ph>>
3715 T Uph-ph>>
110
1
+ a 2 ·U |. For symmetrical voltages this is equivalent to a phase-to-earth voltage.
L2 L3
Setting Options
OFF
Alarm Only
ON
U>Alarm U>>Trip
1.0 .. 170.0 V
0.00 .. 100.00 sec
1.0 .. 170.0 V
0.00 .. 100.00 sec
0.30 .. 0.99
OFF
Alarm Only
ON
U>Alarm U>>Trip
2.0 .. 220.0 V
0.00 .. 100.00 sec
2.0 .. 220.0 V
0.00 .. 100.00 sec
Default Setting Comments
OFF Operating mode Uph-e over-
voltage prot.
85.0 V Uph-e> Pickup
2.00 sec T Uph-e> Time Delay
100.0 V Uph-e>> Pickup
1.00 sec T Uph-e>> Time Delay
0.98 Uph-e>(>) Reset ratio
OFF Operating mode Uph-ph over-
voltage prot.
150.0 V Uph-ph> Pickup
2.00 sec T Uph-ph> Time Delay
175.0 V Uph-ph>> Pickup
1.00 sec T Uph-ph>> Time Delay
C53000-G1176-C159-5, Edition 05.2018
SIPROTEC 4, 7VK61, Manual