ABB REL 356 Current Differential Protection
5-17
Testing
8.
Forward External Faults
For forward Zone 2 Phase-Ground External faults use the Table 5-8 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 beyond the reach of the Zone 3 ground units.
Table 5-8. Zone 3 Phase-Ground Forward External Faults: Z2GF = 7.0 Ohms Z2GR = 0.01 Ohms
Volts
∠
Angle
I
Amps
∠
Angle
Fault Z
Ohms
∠
Angle
Relay System
Operation
AG at MTA 110% of reach fault
Va = 25
∠
0
Ia = 1.95
∠
-75 (285)
7.7
∠
75
Vb = 69
∠
-120 (240)
Ib = 0
Vc = 69
∠
-240 (120)
Ic = 0
No trips
BG at MTA 110% of reach fault
Va = 69
∠
0
Ia = 0
7.7
∠
75
Vb = 25
∠
-120 (240)
Ib = 1.95
∠
-195 (165)
Vc = 69
∠
-240 (120)
Ic = 0
No trips
CG at MTA 110% of reach fault
Va = 69
∠
0
Ia = 0
7.7
∠
75
Vb = 69
∠
-120 (240)
Ib = 0
Vc = 25
∠
-240 (120)
Ic = 1.95
∠
-315 (45)
No trips
9.
Reverse External Faults
For reverse Zone 3 Phase-Ground External faults use the Table 5-9 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 fron the GANG setting.
Table 5-9. Zone 3 Phase-Ground Reverse External Faults: Z2GF = 7.0 Ohms Z2GR = 0.01 Ohms
Volts
∠
Angle
I
Amps
∠
Angle
Fault Z
Ohms
∠
Angle
Relay System
Operation
AG at MTA -180˚ 50% of reach fault
Va = 25
∠
0
Ia = 4.29
∠
-255 (105)
3.5
∠
-105
Vb = 69
∠
-120 (240)
Ib = 0
Vc = 69
∠
-240 (120)
Ic = 0
No trips
BG at MTA –180˚ 50% of reach fault
Va = 69
∠
0
Ia = 0
3.5
∠
-105
Vb = 25
∠
-120 (240)
Ib = 4.29
∠
-15 (345)
Vc = 69
∠
-240 (120)
Ic = 0
No trips
CG at MTA –180˚ 50% of reach fault
Va = 69
∠
0
Ia = 0
3.5
∠
-105
Vb = 69
∠
-120 (240)
Ib = 0
Vc = 25
∠
-240 (120)
Ic = 4.29
∠
-135 (225)
No trips
Summary of Contents for REL 356
Page 23: ...ABB REL 356 Current Differential Protection 1 10 Product Overview and Specifications ...
Page 83: ...ABB REL 356 Current Differential Protection 3 36 Settings and Application ...
Page 127: ...ABB REL 356 Current Differential Protection 5 28 Testing ...
Page 186: ...LINE SECTIONALIZING USING A PLC AND ABB PROTECTIVE RELAY Page 49 of 53 ...
Page 187: ...LINE SECTIONALIZING USING A PLC AND ABB PROTECTIVE RELAY Page 50 of 53 ...
Page 188: ...LINE SECTIONALIZING USING A PLC AND ABB PROTECTIVE RELAY Page 51 of 53 ...
Page 189: ...LINE SECTIONALIZING USING A PLC AND ABB PROTECTIVE RELAY Page 52 of 53 ...