ABB REL 356

ABB REL 356 Current Differential Protection
5-22
Testing
Zone 2 3-Phase Units
NOTE: Set the “T3P” timer setting to “BLK” before applying the faults in Tables 5-16, 5-17, and 5-18.
16. Forward Internal Faults
For forward Zone 2 Three-Phase Internal faults use the Table 5-16 of voltages and currents. In each case apply the 3-
phase voltage to the relay system first then suddenly apply the currents listed. Compare the relay system trip target
data to the applied fault values. The target data should be within +/- 10% magnitude and +/- 3 degrees on phase. Trip
time should fall within 100 - 132 milliseconds.
Table 5-16. Zone 2 Three-Phase Forward Internal Faults: Z2P = 4.5 Ohms
Volts
∠
Angle
I
Amps
∠
Angle
Fault Z
Ohms
∠
Angle
Relay System
Operation
BC at MTA 90% of reach fault
Va = 20
∠
0 Ia = 4.93
∠
-75 (285) 4.05
∠
75
Vb = 20
∠
-120 (240) Ib = 4.93
∠
-195 (165)
Vc = 20 ∠ -240 (120) Ic = 4.93 ∠ -315 (45)
Z2T Trip
Fault type ABC
Z2P Unit
Trip time 100-132 mS
17. Forward External Faults
For forward Zone 2 Three-Phase External faults use the Table 5-17 of voltages and currents. In each case apply the 3-
phase voltage to the relay system first then suddenly apply the currents listed. The relay system should not trip as
these faults are beyond the reach of the Zone 2 Three-Phase units.
Table 5-17. Zone 2 Three-Phase Forward External Faults: Z2P = 4.5 Ohms
Volts
∠
Angle
I
Amps
∠
Angle
Fault Z
Ohms
∠
Angle
Relay System
Operation
BC at MTA 110% of reach fault
Va = 20
∠
0 Ia = 4.04
∠
-75 (285) 4.95
∠
75
Vb = 20
∠
-120 (240) Ib = 4.04
∠
-195 (165)
Vc = 20 ∠ -240 (120) Ic = 4.04 ∠ -315 (45)
No Trips
18. Reverse External Faults
For reverse Zone 2 Three-Phase External faults use the Table 5-18 of voltages and currents. In each case apply the 3-
phase voltage to the relay system first then suddenly apply the currents listed. In each case the relay system should
not trip as these faults are reverse direction from the PANG setting.
Table 5-18. Zone 2 Three-Phase Reverse External Faults: Z2P = 4.5 Ohms
Volts
∠
Angle
I
Amps
∠
Angle
Fault Z
Ohms
∠
Angle
Relay System
Operation
Va = 20
∠
0 Ia = 8.89
∠
-255 (105) 2.25
∠
-105
Vb = 20
∠
-120 (240) Ib = 8.89
∠
-15 (345)
Vc = 20 ∠ -240 (120) Ic = 8.89 ∠ -135 (225)
No Trips