Settings - Siemens Siprotec 7VK61 Manual

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 criterion
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 relay is operated without current transformer connection, the current criterion is of no use and as-
sociated parameters are hidden.
Undervoltage positive sequence system U
The positive sequence undervoltage stages can be used instead of or in addition to previously mentioned un-
dervoltage 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 3774) with a shorter time delay T U1<< (address 3775).
Note that the positive sequence system is established according to its defining equation
1
U = / ·|U + a·U
1 3 L1
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 criterion
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 picked-
up state. It must therefore be ensured in such cases that the protection is blocked by a binary input.
If the 7VK61 relay is operated without current transformer connection, the current criterion is of no use and as-
sociated parameters are hidden.
2.5.4

Settings

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>
SIPROTEC, 7VK61, Manual
C53000-G1176-C159-3, Release date 05.2009
1
2
+ a ·U |. For symmetrical voltages this is equivalent to a phase-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; ∞
2.5 Under and over-voltage protection (optional)
Default Setting
OFF Operating mode Uph-e overvolt-
age 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 overvolt-
age prot.
150.0 V Uph-ph> Pickup
Functions
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