ABB REL 356

ABB REL 356 Current Differential Protection
5-20
Testing
Zone 3 Phase-Phase Element
NOTE: Change the “T3P” timer setting to 1.0 seconds before applying the faults in Tables 5-13, 5-14, and 5-15.
13. Forward Internal Faults
For forward Zone 3 Phase-Ground Internal faults use the Table 5-13 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 1.00 - 1.05 seconds.
Table 5-13. Zone 3 Phase-Phase Forward Internal Faults: Z3P = 7.0 Ohms
Volts
∠
Angle
I
Amps
∠
Angle
Fault Z
Ohms
∠
Angle
Relay System
Operation
AB at MTA 90% of reach fault
Va = 17.3
∠
0 Ia = 2.38
∠
-45 (315) 6.3
∠
75
Vb = 17.3
∠
-120 (240) Ib = 2.38
∠
-225 (135)
Vc = 69 ∠ -240 (120) Ic = 0
Z3T Trip
Fault type AB
Z3P Unit
Trip time 1.0-1.05 mS
BC at MTA 90% of reach fault
Va = 69
∠
0 Ia = 0 6.3
∠
75
Vb = 1.73 ∠ -120 (240) Ib = 2.38 ∠ -165 (195)
Vc = 1.73 ∠ -240 (120) Ic = 2.38 ∠ -345 (15)
Z3T Trip
Fault type BC
Z3P Unit
Trip time 1.0-1.05 mS
CA at MTA 90% of reach fault
Va = 17.3
∠
0 Ia = 2.38
∠
-105 (255) 6.3
∠
75
Vb = 69 ∠ -120 (240) Ib = 0
Vc = 17.3
∠
-240 (120) Ic = 2.38
∠
-285 (75)
Z3T Trip
Fault type CA
Z3P Unit
Trip time 1.0-1.05 mS
14. Forward External Faults
For forward Zone 3 Phase-Phase External faults use the Table 5-14 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 3 Phase units.
Table 5-14. Zone 3 Phase-Phase Forward External Faults: Z3P = 7.0 Ohms
Volts
∠
Angle
I
Amps
∠
Angle
Fault Z
Ohms
∠
Angle
Relay System
Operation
AB at MTA 110% of reach fault
Va = 17.3
∠
0 Ia = 1.95
∠
-45 (315) 7.7
∠
75
Vb = 17.3 ∠ -120 (240) Ib = 1.95 ∠ -225 (135)
Vc = 69 ∠ -240 (120) Ic = 0
No Trips
BC at MTA 110% of reach fault
Va = 69
∠
0 Ia = 0 7.7
∠
75
Vb = 1.73 ∠ -120 (240) Ib = 1.95 ∠ -165 (195)
Vc = 1.73 ∠ -240 (120) Ic = 1.95 ∠ -345 (15)
No Trips
CA at MTA 110% of reach fault
Va = 17.3
∠
0 Ia = 1.95
∠
-105 (255) 7.7
∠
75
Vb = 69 ∠ -120 (240) Ib = 0
Vc = 17.3 ∠ -240 (120) Ic = 1.95 ∠ -285 (75)
No Trips