![background image](http://html1.mh-extra.com/html/vamp/210/210_operation-and-configuration-instructions_3324090048.webp)
VAMP 210
Generator protection relay
Technical description
VAMP Ltd
14
Vamp 24h support phone: +358 (0)20 753 3264
VM210.EN004
2.2.2.
Voltage restrained and voltage controlled
overcurrent function (51V)
The voltage restrained overcurrent stage I
V
> is used for
generator short-circuit protection in applications, where the
static excitation system of the generator is fed from the
generator terminals.
In these applications the operation of the overcurrent function
must be secured using a voltage restrained overcurrent
function. At close-by short circuits the fault current rapidly
decreases, thus jeopardizing the operation of the main short-
circuit protection. The operation characteristic of a voltage
restrained overcurrent function is shown in Figure 2.2.2-1.
Figure 2.2.2-1 Characteristics of a voltage restrained overcurrent function
I
V
>.
When the generator pole voltage falls below the set voltage
level, the start current level of the overcurrent stage I
V
> also
starts falling linearly controlled by the voltage according to the
characteristic curve in Figure 2.2.2-1.
When the setting parameters are selected according to Figure
2.2.2-2 the function is said to be voltage controlled.
Note: The overcurrent function can be used as a normal high-
set overcurrent stage I>>>, if I
Y1
and I
Y2
are set to 100%.