ISA T1000 PLUS User Manual page 95

DOC. MIE91093
SUPPLY FAULT
3 PHASE ANY
1 PHASE PHASE 1
PHASE 2
PHASE 3
3) Zone limits test
Given the fault impedances Z1, Z2, Z3, Z4 of the zone limits,
compute as follows the corresponding fault voltages V1, V2,
V3, V4:
Vf = Z*If*(1+KoL)
For instance: KoL = 1; If = 10 A
Vf = 20 * Z
These voltages are the limits between following zones, as
follows:
VOLTAGE <
V1
TIMING T1
ZONE 1
LIMIT
Where: T1, T2, T3, T4 are respectively the time settings for
zones 1, 2, 3, 4 (case of three zones plus the starter).
Once fault current and pre-fault voltage amplitudes have been
adjusted to VN, stop the test and start again. Adjust the fault
voltage of the selected phase at a value slightly less than V1,
VT11: the trip time should be the one of zone 1. Slightly
increase the fault voltage and start again with value VT12: trip
time should become T2. The procedure can be repeated at
will, until the first zone is checked with the desired accuracy:
the result is
Rev. 1.34
PHASE 1
Φ(I-V)
Φ(I-V)
Φ(I-V)
120°
Φ(I-V)
240°
> < >
V1 V2 V2
T2 T2 T3
2
Page 95 of 145
PHASE 2
Φ(I-V)
Φ(I-V) +
240°
+ Φ(I-V)
+ Φ(I-V) +
120°
< > <
V3 V3 V4
T3 T4 T4
3 STARTER
PHASE 3
Φ(I-V)
Φ(I-V) +
120°
Φ(I-V) +
240°
Φ(I-V)
> V4
NO
TRIP