ABB REL-300, Instruction Leaflet, Page: 107 / 135

I.L. 40-385.1B
(5/92) 6-5
voltages are necessary as directional
reference. The ITG and ITP will automat-
ically become non-directional over-
current units if the setting of LOPB is
YES and at least one input voltage is
zero volts (e.g., LOPB = YES in the me-
tering mode).
Step 21. Using Figure 6-1, configuration #1, to con-
nect currents and voltages, apply AG fault as
shown in Step 1.1.3. The MDAR should trip at I
a
= 5 Amps
±
5 % with a target of ITG-AG. For re-
versed fault, apply 10A reversed fault current
(i.e., I
a
leads Van by 135
°
for Y-connection, or
105
°
for T-connection). The relay should not trip.
Step 22. Using Figure 6-3, to connect currents and
voltages, apply AB fault as shown in Step 1.1.5.
The MDAR should trip at Iab = 10 Amps
±
5%,
with a target of ITP - AB. Apply a 15A reversed
fault current (i.e., I
a
leads V
ab
by 135
°
for Y-con-
nection or 105
°
for T-connection). The relay
should not trip.
1.1.9 Ground Backup (GB) Test
Step 23. Use the SETTINGS mode and change the
following settings:
• ITP = “OUT”
• ITG = “OUT”
• GBCV = CO-8
• GBPU = .5
• GDIR = “NO”
• GTC = 24
NOTE: The note in Step 20 applies to the GB
test. The GB can be set to directional
ground overcurrent. For loss-of-poten-
tial condition, GB will be converted to
non-directional, automatically, regard-
less of the GDIR=YES setting.
Using Figure 6-1, apply A-G fault of 4.1A to MDAR.
Trip time is determined as follows:
(T
MSEC
) =
where
(3I
OF
is zero sequence fault current.)
478
4122
3I
0
1.27 –
-------------------------
+
GTC
24
------------
3I
0
3I
OF
GBPU
----------------- =
The single-phase trip currents for Zone 1, Zone 2,
and Zone 3 at the maximum torque angle
are 6.0A, 4.5A and 3.0A, respectively.
b. Phase-to-Phase Fault
Use the T-connection and the equation in step 13.
Apply the following input voltages:
The single-phase trip currents for Zone 1, Zone 2
and Zone 3 at the maximum torque angle
are 4A, 3A and 2A, respectively.
c. Three-Phase Fault
Use the equation in Step 12 with the following input
voltages:
The three-phase trip currents for Zone 1, Zone 2 and
Zone 3 at the maximum torque angles
should be 6.0A, 4.5A and 3.0A, respectively.
1.1.8 Instantaneous Overcurrent (High-Set
Trip)
Step 20. Using the SETTINGS mode, change the
following settings:
ITP = 10A LOPB = “NO”
ITG = 5A Z3G = “OUT”
Z3P = “OUT”
NOTE: The High-Set ground overcurrent (ITG)
and phase overcurrent (ITP) are super-
vised by Forward Directional Ground
unit (FDOG) and Forward Directional
Phase unit (FDOP), respectively. In or-
der to test the High-Set trip, the 3
φ
I
A
75
° ∠ ( )
V
AN
18 0
° ∠
1
2
--- V
F
= =
V
BN
18 180
°
–
∠
1
2
--- V
F
= =
V
CN
105 90
° ∠
=
I
AB
75
°
–
∠ ( )
V
AN
27 0
° ∠
V
LN
= =
V
BN
27 120
°
–
∠
=
V
CN
27 120
° ∠
=
I
A
75
°
, I
B
195
°
, I
C
+45
° ∠
–
∠
–
∠ ( )