VAMP 257 - Broken Conductor Protection (46)

VAMP Ltd Feeder and motor manager
Technical description
VAMP 257
VM257.EN002 VAMP 24h support phone : +358 (0)20 753 3264
33
Measured and recorded values of directional overcurrent
stages:
I
dir
>, I
dir
>>, I
dir
>>> and I
dir
>>>> (67)
Parameter Value Unit Description
ILmax A Corresponding primary value
U1 V Positive sequence voltage
Measured
value
ϕ °
Active power angle
SCntr - Cumulative start counter
TCntr - Cumulative trip counter
1-N, 2-N,
3-N
Fault type/single-phase fault,
e.g. 1-N = fault on phase L1
1-2, 2-3,
1-3
e.g. 2-3 = fault between L2
and L3
Type
1-2-3 Fault type/three-phase fault
U1 V Positive sequence voltage
ϕ °
Active power angle
Flt xImode Max. fault current
Load xImode
1 s mean value of pre-fault
phase currents IL1…IL3
Recorded
values
EDly %
The elapsed time compared
to the set operating time,
100% = tripping
2.3.5. Broken conductor protection (46)
The purpose of the broken conductor protection is to detect
unbalanced load conditions, for example a broken wire of a
heavy loaded overhead line in case there is no earth fault.
The operation of the unbalanced load function is based on the
negative phase sequence component I
2
related to the positive
phase sequence component I
1
. This is calculated from the phase
currents using the method of symmetrical components. The
function requires that the measuring inputs are connected
correctly so that the rotation direction of the phase currents are
as in Figure 4.10.1-1. The unbalance protection has definite
time operation characteristic.
Setting parameters of unbalanced load function:
I
2
/I
1
> (46)
Parameter Value Unit Default Description
I2/I1> 2 … 70 % 20 Setting value, I2/I1
t> 1.0 … 600.0 s 10.0 Definite operating time
Type DT
INV
- DT
The selection of time
characteristics
S_On
Enabled;
Disabled
- Enabled Start on event
S_Off
Enabled;
Disabled
- Enabled Start off event
T_On
Enabled;
Disabled
- Enabled Trip on event