Relay Protection Functions; Overcurrent Protection I>, I>>, I>>> (50/51) - VAMP 140 Operation And Configuration Instructions

VAMP Ltd
2.2.
2.2.1.
VM140.EN011
Overcurrent and earth-fault relay
Technical description

Relay protection functions

Overcurrent protection I>, I>>, I>>> (50/51)
The three-phase overcurrent unit comprises three separately
adjustable overcurrent stages, i.e. stage I>, I>> and I>>>.
The overcurrent unit measures the fundamental frequency
component of the phase currents.
Stage I> can be configured for definite time or inverse time
operation characteristic. Stage I>> and stage I>>> have
definite time characteristic.
Figure 2.2.1-1 shows the functional block diagram of stage I>.
Im1
>
Im2
MAX
Im3
Block
Setting I>s
Figure 2.2.1-1 Block diagram of the three-phase overcurrent stage I>.
Parameters of the overcurrent stages:
I>, I>>, I>>> (50/51)
Parameter:
Measured ILmax
value
Setting I>, I>>,
values I>>>
I>, I>>,
I>>>
Curve
t>, t>>,
t>>>
k
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&
t t
s r
t
Delay Definite / inverse Inverse time
time characteristics
Value/unit:
A
A
pu
DT
NI, VI
EI, LTI
s
3vIslohko
&
³1
&
Multiplier Enable events
Max. value of phase currents
IL1, IL2, IL3 primary values
Setting value in primary
current units
Setting value as per unit
value. Setting done in xIn
Operation charact./ definite
time (I>)
Operation charact./ inverse
time (I>)
Operation time
Time multiplier at inverse
time (I>)
VAMP 140
Start
Register
event
Trip
Register
event
7